Add MTU to neutron networks and nic-config templates

Neutron has support[1] to set the guaranteed MTU for
networks and network segments so that this is exposed
to plug-ins. In interest of supporting the use of
plug-ins to configure network devices in the future
this change adds MTU property on neutron networks.

The new (optional) property 'mtu' in the network
defenitions in 'network_data.yaml' is used to control
the MTU settings. By default the mtu is '1500'.

We already configure the MTU on the ctlplane neutron
networks, this adds the MTU to composable networks.

Also update the nic-config sample templates to include
mtu settings. A heat value resource is added to
nic-config templates to get the required minimum
viable MTU value for bridges, bonds and member
interfaces to ensure the MTU is large enough to allow
the largest configured MTU to traverse the path.

Closes-Bug: #1790537
Change-Id: I11e38f82eb9040f77412fe8ad200fcc48031e2f8

ci/common/net-config-multinode-os-net-config.yaml

@@ -28,6 +28,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   ExternalIpSubnet:
     default: ''
     description: IP address/subnet on the external network
@@ -40,6 +46,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   InternalApiIpSubnet:
     default: ''
     description: IP address/subnet on the internal_api network
@@ -52,6 +64,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -64,6 +82,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -76,6 +100,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   StorageNFSIpSubnet:
     default: ''
     description: IP address/subnet on the storage_nfs network
@@ -100,6 +130,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet:
     default: ''
     description: IP address/subnet on the management network
@@ -112,6 +148,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   OvSBridgeMtu:
     default: 1300
     description: The mtu of the OvS bridge

ci/common/net-config-multinode.yaml

@@ -28,6 +28,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   ExternalIpSubnet:
     default: ''
     description: IP address/subnet on the external network
@@ -40,6 +46,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   InternalApiIpSubnet:
     default: ''
     description: IP address/subnet on the internal_api network
@@ -52,6 +64,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -64,6 +82,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -76,6 +100,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   StorageNFSIpSubnet:
     default: ''
     description: IP address/subnet on the storage_nfs network
@@ -92,6 +122,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet:
     default: ''
     description: IP address/subnet on the management network
@@ -104,6 +140,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/common/net-config-simple-bridge.yaml

@@ -25,6 +25,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   ExternalIpSubnet:
     default: ''
     description: IP address/subnet on the external network
@@ -37,6 +43,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   InternalApiIpSubnet:
     default: ''
     description: IP address/subnet on the internal_api network
@@ -49,6 +61,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -61,6 +79,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -73,6 +97,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   StorageNFSIpSubnet:
     default: ''
     description: IP address/subnet on the storage_nfs network
@@ -89,6 +119,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet:
     default: ''
     description: IP address/subnet on the management network
@@ -101,6 +137,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics-ipv6/nic-configs/ceph-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics-ipv6/nic-configs/cinder-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics-ipv6/nic-configs/compute.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics-ipv6/nic-configs/controller.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics-ipv6/nic-configs/swift-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics/nic-configs/ceph-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics/nic-configs/cinder-storage.yaml

@@ -17,6 +17,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   InternalApiIpSubnet:
     default: ''
     description: IP address/subnet on the internal_api network
@@ -29,6 +35,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +53,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +71,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +89,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +107,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics/nic-configs/compute.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics/nic-configs/controller.yaml

@@ -17,6 +17,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   InternalApiIpSubnet:
     default: ''
     description: IP address/subnet on the internal_api network
@@ -29,6 +35,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +53,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +71,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +89,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +107,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/multiple-nics/nic-configs/swift-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/public-bond/nic-configs/ceph-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/public-bond/nic-configs/cinder-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/public-bond/nic-configs/compute.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/public-bond/nic-configs/controller.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

ci/environments/network/public-bond/nic-configs/swift-storage.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  InternalApiMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      InternalApi network.
+    type: number
   StorageIpSubnet:
     default: ''
     description: IP address/subnet on the storage network
@@ -41,6 +47,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Storage network.
+    type: number
   StorageMgmtIpSubnet:
     default: ''
     description: IP address/subnet on the storage_mgmt network
@@ -53,6 +65,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  StorageMgmtMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      StorageMgmt network.
+    type: number
   TenantIpSubnet:
     default: ''
     description: IP address/subnet on the tenant network
@@ -65,6 +83,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  TenantMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Tenant network.
+    type: number
   ManagementIpSubnet: # Only populated when including environments/network-management.yaml
     default: ''
     description: IP address/subnet on the management network
@@ -77,6 +101,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ManagementMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      Management network.
+    type: number
   BondInterfaceOvsOptions:
     default: 'bond_mode=active-backup'
     description: The ovs_options string for the bond interface. Set things like
@@ -110,6 +140,12 @@ parameters:
     default: '10.0.0.1'
     description: default route for the external network
     type: string
+  ExternalMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      External network.
+    type: number
   ControlPlaneSubnetCidr:
     default: ''
     description: >
@@ -129,6 +165,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

net-config-bond.j2.yaml

@@ -35,6 +35,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >
@@ -52,6 +58,12 @@ parameters:
     default: ''
     description: IP address/subnet on the {{network.name_lower}} network
     type: string
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
 resources:
   OsNetConfigImpl:

net-config-bridge.j2.yaml

@@ -25,6 +25,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >
@@ -50,6 +56,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
 resources:
   OsNetConfigImpl:

net-config-linux-bridge.j2.yaml

@@ -19,6 +19,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
   ControlPlaneDefaultRoute:
     description: The default route of the control plane network. (The parameter
@@ -39,6 +45,12 @@ parameters:
       The subnet CIDR of the control plane network. (The parameter is
       automatically resolved from the ctlplane subnet's cidr attribute.)
     type: string
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

net-config-noop.j2.yaml

@@ -28,6 +28,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >
@@ -53,6 +59,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
 
 resources:

net-config-standalone.j2.yaml

@@ -20,6 +20,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
   ControlPlaneSubnetCidr:
     default: ''
@@ -40,6 +46,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu: # Here for compatability, not used.
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

net-config-static-bridge-with-external-dhcp.j2.yaml

@@ -20,6 +20,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
   ControlPlaneSubnetCidr:
     default: ''
@@ -40,6 +46,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

net-config-static-bridge.j2.yaml

@@ -20,6 +20,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
   ControlPlaneSubnetCidr:
     default: ''
@@ -40,6 +46,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

net-config-static.j2.yaml

@@ -19,6 +19,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
   ControlPlaneSubnetCidr:
     default: ''
@@ -39,6 +45,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

net-config-undercloud.j2.yaml

@@ -20,6 +20,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
   {%- endfor %}
   ControlPlaneSubnetCidr:
     default: ''
@@ -40,6 +46,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   DnsServers: # Override this via parameter_defaults
     default: []
     description: >

network/config/2-linux-bonds-vlans/role.role.j2.yaml

@@ -26,7 +26,13 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
-{%- for network in networks %}
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
+{%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
 
   {{network.name}}IpSubnet:
     default: ''
@@ -36,6 +42,12 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
@@ -84,6 +96,41 @@ parameters:
 
 
 resources:
+
+  MinViableMtuBondApi:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) and network.name in role.networks and not network.name.startswith('Tenant') %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
+  MinViableMtuBondData:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.name.startswith('Tenant') and network.enabled|default(true) and network.name in role.networks %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -97,6 +144,8 @@ resources:
               network_config:
               - type: interface
                 name: nic1
+                mtu:
+                  get_param: ControlPlaneMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -117,6 +166,8 @@ resources:
 {%- endif %}
               - type: linux_bond
                 name: bond_api
+                mtu:
+                  get_attr: [MinViableMtuBondApi, value]
                 use_dhcp: false
                 bonding_options:
                   get_param: BondInterfaceOvsOptions
@@ -125,12 +176,18 @@ resources:
                 members:
                   - type: interface
                     name: nic2
+                    mtu:
+                      get_attr: [MinViableMtuBondApi, value]
                     primary: true
                   - type: interface
                     name: nic3
+                    mtu:
+                      get_attr: [MinViableMtuBondApi, value]
 {%- for network in networks if network.enabled|default(true) and network.name in role.networks and not network.name.startswith('Tenant') %}
               - type: vlan
                 device: bond_api
+                mtu:
+                  get_param: {{network.name}}Mtu
                 vlan_id:
                   get_param: {{network.name}}NetworkVlanID
                 addresses:
@@ -153,17 +210,25 @@ resources:
                 members:
                 - type: linux_bond
                   name: bond-data
+                  mtu:
+                    get_attr: [MinViableMtuBondData, value]
                   bonding_options:
                     get_param: BondInterfaceOvsOptions
                   members:
                   - type: interface
                     name: nic4
+                    mtu:
+                      get_attr: [MinViableMtuBondData, value]
                     primary: true
                   - type: interface
                     name: nic5
+                    mtu:
+                      get_attr: [MinViableMtuBondData, value]
   {%- for network in networks if network.name.startswith('Tenant') and network.name in role.networks and network.enabled|default(true) %}
               - type: vlan
                 device: bond-data
+                mtu:
+                  get_param: {{network.name}}Mtu
                 vlan_id:
                   get_param: {{network.name}}NetworkVlanID
                 addresses:

network/config/bond-with-vlans/controller-no-external.j2.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -38,6 +44,12 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'

network/config/bond-with-vlans/controller-v6.j2.yaml

@@ -27,6 +27,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -36,6 +42,12 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
@@ -75,6 +87,24 @@ parameters:
       for OVS bonds or like mode=4 for Linux bonds using this option.'
     type: string
 resources:
+
+  MinViableMtu:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -88,6 +118,8 @@ resources:
               network_config:
               - type: interface
                 name: nic1
+                mtu:
+                  get_param: ControlPlaneMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -106,20 +138,30 @@ resources:
                         get_param: ControlPlaneDefaultRoute
               - type: ovs_bridge
                 name: bridge_name
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 dns_servers:
                   get_param: DnsServers
                 members:
                 - type: ovs_bond
                   name: bond1
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   ovs_options:
                     get_param: BondInterfaceOvsOptions
                   members:
                   - type: interface
                     name: nic2
+                    mtu:
+                      get_attr: [MinViableMtu, value]
                     primary: true
                   - type: interface
                     name: nic3
+                    mtu:
+                      get_attr: [MinViableMtu, value]
                 - type: vlan
+                  mtu:
+                    get_attr: [ExternalMtu, value]
                   vlan_id:
                     get_param: ExternalNetworkVlanID
                   addresses:
@@ -132,6 +174,8 @@ resources:
                           next_hop:
                             get_param: ExternalInterfaceDefaultRoute
                 - type: vlan
+                  mtu:
+                    get_attr: [InternalApiMtu, value]
                   vlan_id:
                     get_param: InternalApiNetworkVlanID
                   addresses:
@@ -140,6 +184,8 @@ resources:
                   routes:
                     get_param: InternalApiInterfaceRoutes
                 - type: vlan
+                  mtu:
+                    get_attr: [StorageMtu, value]
                   vlan_id:
                     get_param: StorageNetworkVlanID
                   addresses:
@@ -148,6 +194,8 @@ resources:
                   routes:
                     get_param: StorageInterfaceRoutes
                 - type: vlan
+                  mtu:
+                    get_attr: [StorageMgmtMtu, value]
                   vlan_id:
                     get_param: StorageMgmtNetworkVlanID
                   addresses:
@@ -156,6 +204,8 @@ resources:
                   routes:
                     get_param: StorageMgmtInterfaceRoutes
                 - type: vlan
+                  mtu:
+                    get_attr: [TenantMtu, value]
                   vlan_id:
                     get_param: TenantNetworkVlanID
                   addresses:
@@ -168,6 +218,8 @@ resources:
                 # out the default route on the External interface. This will
                 # make the External API unreachable from remote subnets.
                 #- type: vlan
+                #  mtu:
+                #    get_attr: [ManagementMtu, value]
                 #  vlan_id:
                 #    get_param: ManagementNetworkVlanID
                 #  addresses:

network/config/bond-with-vlans/role.role.j2.yaml

@@ -25,6 +25,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks if network.enabled|default(true) and network.name in role.networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -34,17 +40,23 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
-{%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
+{%-     if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- elif network.gateway_ip|default(false) %}
+{%-     elif network.gateway_ip|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ip}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- endif %}
+{%-     endif %}
   {{network.name}}InterfaceRoutes:
     default: []
     description: >
@@ -79,6 +91,24 @@ parameters:
     type: number
 {%- endif %}
 resources:
+
+  MinViableMtu:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -92,6 +122,8 @@ resources:
               network_config:
               - type: interface
                 name: nic1
+                mtu:
+                  get_param: ControlPlaneMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -112,26 +144,34 @@ resources:
 {%- endif %}
 {%- if not role.name.startswith('ComputeOvsDpdk') %}
               - type: ovs_bridge
-{%- if role.name.startswith('CephStorage') or role.name.startswith('ObjectStorage') or role.name.startswith('BlockStorage') %}
+{%-     if role.name.startswith('CephStorage') or role.name.startswith('ObjectStorage') or role.name.startswith('BlockStorage') %}
                 name: br-bond
-{%- else %}
+{%-     else %}
                 name: bridge_name
-{%- endif %}
+{%-     endif %}
                 dns_servers:
                   get_param: DnsServers
                 members:
                 - type: ovs_bond
                   name: bond1
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   ovs_options:
                     get_param: BondInterfaceOvsOptions
                   members:
                   - type: interface
                     name: nic2
+                    mtu:
+                      get_attr: [MinViableMtu, value]
                     primary: true
                   - type: interface
                     name: nic3
-{%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
+                    mtu:
+                      get_attr: [MinViableMtu, value]
+{%-     for network in networks if network.enabled|default(true) and network.name in role.networks %}
                 - type: vlan
+                  mtu:
+                    get_param: {{network.name}}Mtu
                   vlan_id:
                     get_param: {{network.name}}NetworkVlanID
                   addresses:
@@ -140,16 +180,18 @@ resources:
                   routes:
                     list_concat_unique:
                       - get_param: {{network.name}}InterfaceRoutes
-{%- if network.name in role.default_route_networks %}
+{%-         if network.name in role.default_route_networks %}
                       - - default: true
                           next_hop:
                             get_param: {{network.name}}InterfaceDefaultRoute
-{%- endif %}
+{%-         endif %}
-{%- endfor %}
+{%-     endfor %}
 {%- else %}
               # Linux bond for non-DPDK traffic required when using DPDK
               - type: linux_bond
                 name: bond_api
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 bonding_options:
                   get_param: BondInterfaceOvsOptions
                 use_dhcp: false
@@ -158,12 +200,18 @@ resources:
                 members:
                 - type: interface
                   name: nic2
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   primary: true
                 - type: interface
                   name: nic3
-{%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
+                  mtu:
+                    get_attr: [MinViableMtu, value]
+{%-     for network in networks if network.enabled|default(true) and network.name in role.networks %}
               - type: vlan
                 device: bond_api
+                mtu:
+                  get_param: {{network.name}}Mtu
                 vlan_id:
                   get_param: {{network.name}}NetworkVlanID
                 addresses:
@@ -172,12 +220,12 @@ resources:
                   routes:
                     list_concat_unique:
                       - get_param: {{network.name}}InterfaceRoutes
-{%- if network.name in role.default_route_networks %}
+{%-         if network.name in role.default_route_networks %}
                       - - default: true
                           next_hop:
                             get_param: {{network.name}}InterfaceDefaultRoute
-{%- endif %}
+{%-         endif %}
-{%- endfor %}
+{%-     endfor %}
               # Used as a provider network with external DHCP
               - type: ovs_user_bridge
                 name: br-dpdk0

network/config/multiple-nics/compute-dvr.j2.yaml

@@ -27,6 +27,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -36,6 +42,12 @@ parameters:
     default: {{network.vlan|default("")}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
@@ -82,6 +94,8 @@ resources:
               network_config:
               - type: interface
                 name: nic1
+                mtu:
+                  get_param: ControlPlaneMtu
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -102,6 +116,8 @@ resources:
                           get_param: ControlPlaneDefaultRoute
               - type: interface
                 name: nic2
+                mtu:
+                  get_param: StorageMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -110,6 +126,8 @@ resources:
                   get_param: StorageInterfaceRoutes
               - type: interface
                 name: nic4
+                mtu:
+                  get_param: InternalApiMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -118,6 +136,8 @@ resources:
                   get_param: InternalApiInterfaceRoutes
               - type: ovs_bridge
                 name: br-tenant
+                mtu:
+                  get_param: TenantMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -127,23 +147,31 @@ resources:
                 members:
                 - type: interface
                   name: nic5
+                  mtu:
+                    get_param: TenantMtu
                   use_dhcp: false
                   primary: true
               # External bridge for DVR (no IP address required)
               - type: ovs_bridge
                 name: bridge_name
+                mtu:
+                  get_param: ExternalMtu
                 dns_servers:
                   get_param: DnsServers
                 use_dhcp: false
                 members:
                 - type: interface
                   name: nic6
+                  mtu:
+                    get_param: ExternalMtu
                   primary: true
             # Uncomment when including environments/network-management.yaml
             # If setting default route on the Management interface, comment
             # out the default route on the Control Plane.
             #- type: interface
             #  name: nic7
+            #  mtu:
+            #    get_param: ManagementMtu
             #  use_dhcp: false
             #  addresses:
             #    - ip_netmask:

network/config/multiple-nics/controller-v6.j2.yaml

@@ -26,6 +26,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -35,6 +41,12 @@ parameters:
     default: {{network.vlan|default("")}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
@@ -81,6 +93,8 @@ resources:
               network_config:
               - type: interface
                 name: nic1
+                mtu:
+                  get_param: ControlPlaneMtu
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -102,6 +116,8 @@ resources:
                           get_param: ControlPlaneDefaultRoute
               - type: interface
                 name: nic2
+                mtu:
+                  get_param: StorageMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -110,6 +126,8 @@ resources:
                   get_param: StorageInterfaceRoutes
               - type: interface
                 name: nic3
+                mtu:
+                  get_param: StorageMgmtMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -118,6 +136,8 @@ resources:
                   get_param: StorageMgmtInterfaceRoutes
               - type: interface
                 name: nic4
+                mtu:
+                  get_param: InternalApiMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -126,6 +146,8 @@ resources:
                   get_param: InternalApiInterfaceRoutes
               - type: ovs_bridge
                 name: br-tenant
+                mtu:
+                  get_param: TenantMtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -135,10 +157,14 @@ resources:
                 members:
                 - type: interface
                   name: nic5
+                  mtu:
+                    get_param: TenantMtu
                   use_dhcp: false
                   primary: true
               - type: ovs_bridge
                 name: bridge_name
+                mtu:
+                  get_param: ExternalMtu
                 dns_servers:
                   get_param: DnsServers
                 use_dhcp: false
@@ -153,6 +179,8 @@ resources:
                           get_param: ExternalInterfaceDefaultRoute
                 members:
                 - type: interface
+                  mtu:
+                    get_param: ExternalMtu
                   name: nic6
                   primary: true
             # Uncomment when including environments/network-management.yaml
@@ -161,6 +189,8 @@ resources:
             # make the External API unreachable from remote subnets.
             #- type: interface
             #  name: nic7
+            #  mtu:
+            #    get_param: ManagementMtu
             #  use_dhcp: false
             #  addresses:
             #  - ip_netmask:

network/config/multiple-nics/role.role.j2.yaml

@@ -25,6 +25,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks if network.enabled|default(true) and network.name in role.networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -34,17 +40,23 @@ parameters:
     default: {{network.vlan|default("")}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
-{%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
+{%-     if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- elif network.gateway_ip|default(false) %}
+{%-     elif network.gateway_ip|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ip}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- endif %}
+{%-     endif %}
   {{network.name}}InterfaceRoutes:
     default: []
     description: >
@@ -86,6 +98,8 @@ resources:
               network_config:
               - type: interface
                 name: nic1
+                mtu:
+                  get_param: ControlPlaneMtu
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -108,10 +122,12 @@ resources:
 {%- endif %}
 {%- set nics_used = [1] %}
 {%- for network in networks if network.enabled|default(true) and network.name not in role.networks_skip_config|default([]) %}
-{%- if network.name not in ["External", "Tenant"] %}
+{%-     if network.name not in ["External", "Tenant"] %}
-{%- if network.name in role.networks %}
+{%-         if network.name in role.networks %}
               - type: interface
                 name: nic{{loop.index + 1}}
+                mtu:
+                  get_param: {{network.name}}Mtu
                 use_dhcp: false
                 addresses:
                 - ip_netmask:
@@ -119,39 +135,45 @@ resources:
                 routes:
                   list_concat_unique:
                     - get_param: {{network.name}}InterfaceRoutes
-{%- if network.name in role.default_route_networks %}
+{%-             if network.name in role.default_route_networks %}
                     - - default: true
                         next_hop:
                           get_param: {{network.name}}InterfaceDefaultRoute
-{%- endif %}
+{%-             endif %}
-{%- endif %}
+{%-         endif %}
-{%- elif network.name in role.networks or role.name == 'Networker' or role.name == 'ComputeDVR' %}
+{%-     elif network.name in role.networks or role.name == 'Networker' or role.name == 'ComputeDVR' %}
               - type: ovs_bridge
-{%- if network.name == "External" %}
+{%-         if network.name == "External" %}
                 name: bridge_name
-{%- else %}
+{%-         else %}
                 name: br-{{network.name_lower}}
-{%- endif %}
+{%-         endif %}
+                mtu:
+                  get_param: {{network.name}}Mtu
+                dns_servers:
+                  get_param: DnsServers
                 use_dhcp: false
-{%- if network.name in role.networks %}
+{%-         if network.name in role.networks %}
                 addresses:
                 - ip_netmask:
                     get_param: {{network.name}}IpSubnet
                 routes:
                   list_concat_unique:
                     - get_param: {{network.name}}InterfaceRoutes
-{%- if network.name in role.default_route_networks %}
+{%-             if network.name in role.default_route_networks %}
                     - - default: true
                         next_hop:
                           get_param: {{network.name}}InterfaceDefaultRoute
-{%- endif %}
+{%-             endif %}
-{%- endif %}
+{%-         endif %}
                 members:
                 - type: interface
                   name: nic{{loop.index + 1}}
+                  mtu:
+                    get_param: {{network.name}}Mtu
                   use_dhcp: false
                   primary: true
-{%- endif %}
+{%-     endif %}
 {#- This hack gets around Jinja scope limitations to update nics_used within loop. #}
 {%- set _ = nics_used.append(loop.index) %}
 {%- endfor %}

network/config/single-nic-linux-bridge-vlans/controller-v6.j2.yaml

@@ -26,6 +26,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -35,6 +41,12 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
@@ -68,6 +80,24 @@ parameters:
       is automatically resolved from the ctlplane subnet's host_routes attribute.)
     type: string
 resources:
+
+  MinViableMtu:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -81,6 +111,8 @@ resources:
               network_config:
               - type: linux_bridge
                 name: bridge_name
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -102,8 +134,12 @@ resources:
                 members:
                 - type: interface
                   name: interface_name
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   primary: true
               - type: vlan
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 vlan_id:
                   get_param: ExternalNetworkVlanID
                 device: bridge_name
@@ -117,6 +153,8 @@ resources:
                         next_hop:
                           get_param: ExternalInterfaceDefaultRoute
               - type: vlan
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 vlan_id:
                   get_param: InternalApiNetworkVlanID
                 device: bridge_name
@@ -126,6 +164,8 @@ resources:
                 routes:
                   get_param: InternalApiInterfaceRoutes
               - type: vlan
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 vlan_id:
                   get_param: StorageNetworkVlanID
                 device: bridge_name
@@ -135,6 +175,8 @@ resources:
                 routes:
                   get_param: StorageInterfaceRoutes
               - type: vlan
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 vlan_id:
                   get_param: StorageMgmtNetworkVlanID
                 device: bridge_name
@@ -144,6 +186,8 @@ resources:
                 routes:
                   get_param: StorageMgmtInterfaceRoutes
               - type: vlan
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 vlan_id:
                   get_param: TenantNetworkVlanID
                 device: bridge_name
@@ -157,6 +201,8 @@ resources:
               # out the default route on the External interface. This will
               # make the External API unreachable from remote subnets.
               #- type: vlan
+              #  mtu:
+              #    get_attr: [MinViableMtu, value]
               #  vlan_id:
               #    get_param: ManagementNetworkVlanID
               #  device: bridge_name

network/config/single-nic-linux-bridge-vlans/role.role.j2.yaml

@@ -25,6 +25,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks if network.enabled|default(true) and network.name in role.networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -34,17 +40,23 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
-{%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
+{%-     if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- elif network.gateway_ip|default(false) %}
+{%-     elif network.gateway_ip|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ip}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- endif %}
+{%-     endif %}
   {{network.name}}InterfaceRoutes:
     default: []
     description: >
@@ -67,6 +79,24 @@ parameters:
       is automatically resolved from the ctlplane subnet's host_routes attribute.)
     type: string
 resources:
+
+  MinViableMtu:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -84,6 +114,8 @@ resources:
 {%- else %}
                 name: bridge_name
 {%- endif %}
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -107,28 +139,32 @@ resources:
                 members:
                 - type: interface
                   name: interface_name
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   primary: true
 {%- for network in networks if network.enabled|default(true) and network.name in role.networks
     and network.name not in role.networks_skip_config|default([]) %}
               - type: vlan
+                mtu:
+                  get_param: {{network.name}}Mtu
                 vlan_id:
                   get_param: {{network.name}}NetworkVlanID
-{%- if role.name.startswith('CephStorage') or role.name.startswith('ObjectStorage') or role.name.startswith('BlockStorage') %}
+{%-     if role.name.startswith('CephStorage') or role.name.startswith('ObjectStorage') or role.name.startswith('BlockStorage') %}
                 device: br-storage
-{%- else %}
+{%-     else %}
                 device: bridge_name
-{%- endif %}
+{%-     endif %}
                 addresses:
                 - ip_netmask:
                     get_param: {{network.name}}IpSubnet
                 routes:
                     list_concat_unique:
                       - get_param: {{network.name}}InterfaceRoutes
-{%- if network.name in role.default_route_networks %}
+{%-     if network.name in role.default_route_networks %}
                       - - default: true
                           next_hop:
                             get_param: {{network.name}}InterfaceDefaultRoute
-{%- endif %}
+{%-     endif %}
 {%- endfor %}
 outputs:
   OS::stack_id:

network/config/single-nic-vlans/controller-no-external.j2.yaml

@@ -29,6 +29,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -38,6 +44,12 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'

network/config/single-nic-vlans/controller-v6.j2.yaml

@@ -26,6 +26,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -35,6 +41,12 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 {%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
@@ -68,6 +80,24 @@ parameters:
       is automatically resolved from the ctlplane subnet's host_routes attribute.)
     type: string
 resources:
+
+  MinViableMtu:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -81,6 +111,8 @@ resources:
               network_config:
               - type: ovs_bridge
                 name: bridge_name
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -102,8 +134,12 @@ resources:
                 members:
                 - type: interface
                   name: nic1
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   primary: true
                 - type: vlan
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   vlan_id:
                     get_param: ExternalNetworkVlanID
                   addresses:
@@ -116,6 +152,8 @@ resources:
                           next_hop:
                             get_param: ExternalInterfaceDefaultRoute
                 - type: vlan
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   vlan_id:
                     get_param: InternalApiNetworkVlanID
                   addresses:
@@ -124,6 +162,8 @@ resources:
                   routes:
                     get_param: InternalApiInterfaceRoutes
                 - type: vlan
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   vlan_id:
                     get_param: StorageNetworkVlanID
                   addresses:
@@ -132,6 +172,8 @@ resources:
                   routes:
                     get_param: StorageInterfaceRoutes
                 - type: vlan
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   vlan_id:
                     get_param: StorageMgmtNetworkVlanID
                   addresses:
@@ -140,6 +182,8 @@ resources:
                   routes:
                     get_param: StorageMgmtInterfaceRoutes
                 - type: vlan
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   vlan_id:
                     get_param: TenantNetworkVlanID
                   addresses:
@@ -152,6 +196,8 @@ resources:
                 # out the default route on the External interface. This will
                 # make the External API unreachable from remote subnets.
                 #- type: vlan
+                #  mtu:
+                #    get_attr: [MinViableMtu, value]
                 #  vlan_id:
                 #    get_param: ManagementNetworkVlanID
                 #  addresses:

network/config/single-nic-vlans/role.role.j2.yaml

@@ -25,6 +25,12 @@ parameters:
       Unless the default is changed, the parameter is automatically resolved
       from the subnet host_routes attribute.
     type: json
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
 {% for network in networks if network.enabled|default(true) and network.name in role.networks %}
   {{network.name}}IpSubnet:
     default: ''
@@ -34,17 +40,23 @@ parameters:
     default: {{network.vlan}}
     description: Vlan ID for the {{network.name_lower}} network traffic.
     type: number
-{%- if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
+  {{network.name}}Mtu:
+    default: {{network.mtu}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
+{%-     if network.ipv6|default(false) and network.gateway_ipv6|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ipv6}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- elif network.gateway_ip|default(false) %}
+{%-     elif network.gateway_ip|default(false) %}
   {{network.name}}InterfaceDefaultRoute:
     default: '{{network.gateway_ip}}'
     description: default route for the {{network.name_lower}} network
     type: string
-{%- endif %}
+{%-     endif %}
   {{network.name}}InterfaceRoutes:
     default: []
     description: >
@@ -67,6 +79,24 @@ parameters:
       is automatically resolved from the ctlplane subnet's host_routes attribute.)
     type: string
 resources:
+
+  MinViableMtu:
+    # This resource resolves the minimum viable MTU for interfaces, bonds and
+    # bridges that carry multiple VLANs. Each VLAN may have different MTU. The
+    # bridge, bond or interface must have an MTU to allow the VLAN with the
+    # largest MTU.
+    type: OS::Heat::Value
+    properties:
+      type: number
+      value:
+        yaql:
+          expression: $.data.max()
+          data:
+            - {get_param: ControlPlaneMtu}
+{%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
+            - {get_param: {{network.name}}Mtu}
+{%- endfor %}
+
   OsNetConfigImpl:
     type: OS::Heat::SoftwareConfig
     properties:
@@ -84,6 +114,8 @@ resources:
 {%- else %}
                 name: bridge_name
 {%- endif %}
+                mtu:
+                  get_attr: [MinViableMtu, value]
                 use_dhcp: false
                 dns_servers:
                   get_param: DnsServers
@@ -107,10 +139,14 @@ resources:
                 members:
                 - type: interface
                   name: nic1
+                  mtu:
+                    get_attr: [MinViableMtu, value]
                   # force the MAC address of the bridge to this interface
                   primary: true
 {%- for network in networks if network.enabled|default(true) and network.name in role.networks %}
                 - type: vlan
+                  mtu:
+                    get_param: {{network.name}}Mtu
                   vlan_id:
                     get_param: {{network.name}}NetworkVlanID
                   addresses:
@@ -119,11 +155,11 @@ resources:
                   routes:
                     list_concat_unique:
                       - get_param: {{network.name}}InterfaceRoutes
-{%- if network.name in role.default_route_networks %}
+{%-     if network.name in role.default_route_networks %}
                       - - default: true
                           next_hop:
                             get_param: {{network.name}}InterfaceDefaultRoute
-{%- endif %}
+{%-     endif %}
 {%- endfor %}
 outputs:
   OS::stack_id:

network/network.j2

@@ -79,6 +79,12 @@ parameters:
       Routes are added to the host_routes property on the subnet in neutron
       when the network and subnet is created.
     type: json
+  {{network.name}}Mtu:
+    default: {{network.mtu|default('1500')}}
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the
+      {{network.name}} network.
+    type: number
 
 resources:
   {{network.name}}Network:
@@ -87,7 +93,10 @@ resources:
       admin_state_up: {get_param: {{network.name}}NetAdminStateUp}
       name: {get_param: {{network.name}}NetName}
       shared: {get_param: {{network.name}}NetShared}
-      value_specs: {get_param: {{network.name}}NetValueSpecs}
+      value_specs:
+        map_merge:
+          - {get_param: {{network.name}}NetValueSpecs}
+          - {'mtu': {get_param: {{network.name}}Mtu}}
 
   {{network.name}}Subnet:
     type: OS::Neutron::Subnet

network/ports/noop.yaml

@@ -19,6 +19,12 @@ parameters:
     description: The name of the undercloud Neutron control plane subnet
     default: ctlplane-subnet
     type: string
+  ControlPlaneMtu:
+    default: 1500
+    description: The maximum transmission unit (MTU) size(in bytes) that is
+      guaranteed to pass through the data path of the segments in the network.
+      (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+    type: number
   PortName:
     description: Name of the port
     default: ''
@@ -66,3 +72,7 @@ outputs:
   host_routes: # Here for compatibility
     description: Host routes of the ports subnet
     value: []
+  mtu:
+    description: The maximum transmission unit (MTU)
+    value:
+          get_param: ControlPlaneMtu

network/ports/port.j2

@@ -101,3 +101,7 @@ outputs:
     description: Host routes of the ports subnet
     value:
           get_attr: [{{network.name}}Port, subnets, 0, host_routes]
+  mtu:
+    description: The maximum transmission unit (MTU)
+    value:
+          get_attr: [{{network.name}}Port, network, mtu]

network/ports/port_from_pool.j2

@@ -81,4 +81,7 @@ outputs:
   host_routes:
     description: Host routes of the ports subnet
     value: {{network.routes|default([])}}
+  mtu:
+    description: The maximum transmission unit (MTU)
+    value: {{network.mtu|default('1500')}}
 

network_data.yaml

@@ -29,6 +29,9 @@
 # set some default IPv6 addresses.
 # compat_name: for existing stack you may need to override the default
 #              transformation for the resource's name.
+# mtu: Set the maximum transmission unit (MTU) that is guaranteed to pass
+#      through the data path of the segments in the network.
+#      (optional, defaults to 1500)
 #
 # Example:
 # - name Example
@@ -62,6 +65,7 @@
   allocation_pools: [{'start': '172.16.1.4', 'end': '172.16.1.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:3000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:3000::10', 'end': 'fd00:fd00:fd00:3000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: StorageMgmt
   name_lower: storage_mgmt
   vip: true
@@ -70,6 +74,7 @@
   allocation_pools: [{'start': '172.16.3.4', 'end': '172.16.3.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:4000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:4000::10', 'end': 'fd00:fd00:fd00:4000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: InternalApi
   name_lower: internal_api
   vip: true
@@ -78,6 +83,7 @@
   allocation_pools: [{'start': '172.16.2.4', 'end': '172.16.2.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:2000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:2000::10', 'end': 'fd00:fd00:fd00:2000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: Tenant
   vip: false  # Tenant network does not use VIPs
   name_lower: tenant
@@ -87,6 +93,7 @@
   # Note that tenant tunneling is only compatible with IPv4 addressing at this time.
   ipv6_subnet: 'fd00:fd00:fd00:5000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:5000::10', 'end': 'fd00:fd00:fd00:5000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: External
   vip: true
   name_lower: external
@@ -97,6 +104,7 @@
   ipv6_subnet: '2001:db8:fd00:1000::/64'
   ipv6_allocation_pools: [{'start': '2001:db8:fd00:1000::10', 'end': '2001:db8:fd00:1000:ffff:ffff:ffff:fffe'}]
   gateway_ipv6: '2001:db8:fd00:1000::1'
+  mtu: 1500
 - name: Management
   # Management network is enabled by default for backwards-compatibility, but
   # is not included in any roles by default. Add to role definitions to use.
@@ -110,3 +118,4 @@
   gateway_ipv6: 'fd00:fd00:fd00:6000::1'
   ipv6_subnet: 'fd00:fd00:fd00:6000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:6000::10', 'end': 'fd00:fd00:fd00:6000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500

network_data_ganesha.yaml

@@ -26,6 +26,9 @@
 # set some default IPv6 addresses.
 # compat_name: for existing stack you may need to override the default
 #              transformation for the resource's name.
+# mtu: Set the maximum transmission unit (MTU) that is guaranteed to pass
+#      through the data path of the segments in the network.
+#      (optional, defaults to 1500)
 #
 # Example:
 # - name Example
@@ -59,6 +62,7 @@
   allocation_pools: [{'start': '172.16.1.4', 'end': '172.16.1.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:3000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:3000::10', 'end': 'fd00:fd00:fd00:3000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: StorageMgmt
   name_lower: storage_mgmt
   vip: true
@@ -67,6 +71,7 @@
   allocation_pools: [{'start': '172.16.3.4', 'end': '172.16.3.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:4000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:4000::10', 'end': 'fd00:fd00:fd00:4000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: InternalApi
   name_lower: internal_api
   vip: true
@@ -75,6 +80,7 @@
   allocation_pools: [{'start': '172.16.2.4', 'end': '172.16.2.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:2000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:2000::10', 'end': 'fd00:fd00:fd00:2000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: Tenant
   vip: false  # Tenant network does not use VIPs
   name_lower: tenant
@@ -84,6 +90,7 @@
   # Note that tenant tunneling is only compatible with IPv4 addressing at this time.
   ipv6_subnet: 'fd00:fd00:fd00:5000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:5000::10', 'end': 'fd00:fd00:fd00:5000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: External
   vip: true
   name_lower: external
@@ -94,6 +101,7 @@
   ipv6_subnet: '2001:db8:fd00:1000::/64'
   ipv6_allocation_pools: [{'start': '2001:db8:fd00:1000::10', 'end': '2001:db8:fd00:1000:ffff:ffff:ffff:fffe'}]
   gateway_ipv6: '2001:db8:fd00:1000::1'
+  mtu: 1500
 - name: Management
   # Management network is enabled by default for backwards-compatibility, but
   # is not included in any roles by default. Add to role definitions to use.
@@ -107,6 +115,7 @@
   gateway_ipv6: 'fd00:fd00:fd00:6000::1'
   ipv6_subnet: 'fd00:fd00:fd00:6000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:6000::10', 'end': 'fd00:fd00:fd00:6000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500
 - name: StorageNFS
   enabled: true
   vip: true
@@ -116,3 +125,4 @@
   allocation_pools: [{'start': '172.16.4.4', 'end': '172.16.4.250'}]
   ipv6_subnet: 'fd00:fd00:fd00:7000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:7000::10', 'end': 'fd00:fd00:fd00:7000:ffff:ffff:ffff:fffe'}]
+  mtu: 1500

network_data_routed.yaml

@@ -40,6 +40,9 @@
 # set some default IPv6 addresses.
 # compat_name: for existing stack you may need to override the default
 #              transformation for the resource's name.
+# mtu: Set the maximum transmission unit (MTU) that is guaranteed to pass
+#      through the data path of the segments in the network.
+#      (optional, defaults to 1500)
 #
 # Example:   # A single 10.0.0.0/16 route works for up to 255 /24 networks
 # - name Example1
@@ -83,6 +86,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:3000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:3000::10', 'end': 'fd00:fd00:fd00:3000:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:3004::/64', 'nexthop':'fd00:fd00:fd00:3000::1'}]
+  mtu: 1500
 - name: StorageLeaf2
   vip: false
   vlan: 31
@@ -94,6 +98,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:3004::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:3004::10', 'end': 'fd00:fd00:fd00:3004:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:3000::/64', 'nexthop':'fd00:fd00:fd00:3004::1'}]
+  mtu: 1500
 - name: StorageMgmt
   name_lower: storage_mgmt
   vip: true
@@ -105,6 +110,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:4000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:4000::10', 'end': 'fd00:fd00:fd00:4000:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:4004::/64', 'nexthop':'fd00:fd00:fd00:4000::1'}]
+  mtu: 1500
 - name: StorageMgmtLeaf2
   name_lower: storage_mgmt2
   vip: false
@@ -116,6 +122,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:4004::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:4004::10', 'end': 'fd00:fd00:fd00:4004:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:4000::/64', 'nexthop':'fd00:fd00:fd00:4004::1'}]
+  mtu: 1500
 - name: InternalApi
   name_lower: internal_api
   vip: true
@@ -127,6 +134,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:2000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:2000::10', 'end': 'fd00:fd00:fd00:2000:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:2004::/64', 'nexthop':'fd00:fd00:fd00:2000::1'}]
+  mtu: 1500
 - name: InternalApiLeaf2
   name_lower: internal_api2
   vip: false
@@ -138,6 +146,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:2004::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:2004::10', 'end': 'fd00:fd00:fd00:2004:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:2000::/64', 'nexthop':'fd00:fd00:fd00:2004::1'}]
+  mtu: 1500
 - name: Tenant
   vip: false  # Tenant networks do not use VIPs
   name_lower: tenant
@@ -150,6 +159,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:5000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:5000::10', 'end': 'fd00:fd00:fd00:5000:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:5004::/64', 'nexthop':'fd00:fd00:fd00:5000::1'}]
+  mtu: 1500
 - name: TenantLeaf2
   vip: false  # Tenant networks do not use VIPs
   name_lower: tenant2
@@ -162,6 +172,7 @@
   ipv6_subnet: 'fd00:fd00:fd00:5004::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:5004::10', 'end': 'fd00:fd00:fd00:5004:ffff:ffff:ffff:fffe'}]
   routes_ipv6: [{'destination':'fd00:fd00:fd00:5000::/64', 'nexthop':'fd00:fd00:fd00:5004::1'}]
+  mtu: 1500
 - name: External
   vip: true
   name_lower: external
@@ -172,6 +183,7 @@
   ipv6_subnet: '2001:db8:fd00:1000::/64'
   ipv6_allocation_pools: [{'start': '2001:db8:fd00:1000::10', 'end': '2001:db8:fd00:1000:ffff:ffff:ffff:fffe'}]
   gateway_ipv6: '2001:db8:fd00:1000::1'
+  mtu: 1500
 - name: Management
   # Management network is enabled by default for backwards-compatibility, but
   # is not included in any roles by default. Add to role definitions to use.
@@ -185,3 +197,4 @@
   ipv6_subnet: 'fd00:fd00:fd00:6000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:6000::10', 'end': 'fd00:fd00:fd00:6000:ffff:ffff:ffff:fffe'}]
   gateway_ipv6: 'fd00:fd00:fd00:6000::1'
+  mtu: 1500

puppet/role.role.j2.yaml

@@ -509,6 +509,7 @@ resources:
           - ctlplane_static_routes_set
           - {get_param: ControlPlaneStaticRoutes}
           - {get_attr: [{{server_resource_name}}, addresses, ctlplane, 0, subnets, 0, host_routes]}
+      ControlPlaneMtu: {get_attr: [{{server_resource_name}}, addresses, ctlplane, 0, network, mtu]}
       EC2MetadataIp:
         if:
           - ec2metadaip_set
@@ -532,6 +533,7 @@ resources:
           - {{network.name_lower}}_interface_routes_set
           - {get_param: {{network.name}}InterfaceRoutes}
           - {get_attr: [{{network.name}}Port, host_routes]}
+      {{network.name}}Mtu: {get_attr: [{{network.name}}Port, mtu]}
   {%- endif %}
   {%- endfor %}
 

releasenotes/notes/network-templates-mtu-setting-a76fe47cfc97b36f.yaml

@@ -0,0 +1,58 @@
+---
+features:
+  - |
+    The network data for composible networks have been extended to enable
+    configuration of the  maximum transmission unit (MTU) that is guaranteed to
+    pass through the data path of the segments in the network. The MTU property
+    is set on the neutron networks in the undercloud. The MTU information
+    is used in the nic-config templates so that overcloud node networking is
+    configured with the correct MTU settings.
+upgrade:
+  - |
+    Prior to upgrading any custom nic-config templates must have the MTU
+    associated parameters introduced in this release added. As an example the
+    following must be added to all nic-config templates when network isolation
+    is used::
+
+      ControlPlaneMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the network.
+          (The parameter is automatically resolved from the ctlplane network's mtu attribute.)
+        type: number
+      StorageMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the
+          Storage network.
+        type: number
+      StorageMgmtMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the
+          StorageMgmt network.
+        type: number
+      InternalApiMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the
+          InternalApi network.
+        type: number
+      TenantMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the
+          Tenant network.
+        type: number
+      ExternalMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the
+          External network.
+        type: numbe
+      ManagementMtu:
+        default: 1500
+        description: The maximum transmission unit (MTU) size(in bytes) that is
+          guaranteed to pass through the data path of the segments in the
+          Management network.
+        type: number