Improve automation of seed VM network configuration

The list of libvirt networks is now generated from the seed's network interfaces.
This can be overridden if necessary.

ansible/filter_plugins/networks.py

@@ -121,6 +121,17 @@ net_mtu = _make_attr_filter('mtu')
 net_routes = _make_attr_filter('routes')
 
 
+@jinja2.contextfilter
+def net_libvirt_network_name(context, name, inventory_hostname=None):
+    """Return the configured Libvirt name for a network.
+
+    If no Libvirt name is configured, the network's name is returned.
+    """
+    libvirt_name = net_attr(context, name, 'libvirt_network_name',
+                            inventory_hostname)
+    return libvirt_name or name
+
+
 @jinja2.contextfilter
 def net_bridge_ports(context, name, inventory_hostname=None):
     return net_attr(context, name, 'bridge_ports', inventory_hostname)
@@ -273,6 +284,35 @@ def net_configdrive_network_device(context, name, inventory_hostname=None):
     return interface
 
 
+@jinja2.contextfilter
+def net_libvirt_network(context, name, inventory_hostname=None):
+    """Return a dict which describes the Libvirt network for a network.
+
+    The Libvirt network is in a form accepted by the libvirt-host role.
+    """
+    interface = net_interface(context, name, inventory_hostname)
+    name = net_libvirt_network_name(context, name, inventory_hostname)
+    return {
+        "name": name,
+        "mode": "bridge",
+        "bridge": interface,
+    }
+
+
+@jinja2.contextfilter
+def net_libvirt_vm_network(context, name, inventory_hostname=None):
+    """Return a dict which describes the Libvirt VM's network for a network.
+
+    The Libvirt network is in a form accepted by the libvirt_vm_interfaces
+    variable of the libvirt-vm role.
+    """
+    libvirt_name = net_libvirt_network_name(context, name, inventory_hostname)
+    return {
+        "network": libvirt_name,
+        "net_name": name,
+    }
+
+
 class FilterModule(object):
     """Networking filters."""
 
@@ -306,4 +346,7 @@ class FilterModule(object):
             'net_select_vlans': net_select_vlans,
             'net_reject_vlans': net_reject_vlans,
             'net_configdrive_network_device': net_configdrive_network_device,
+            'net_libvirt_network_name': net_libvirt_network_name,
+            'net_libvirt_network': net_libvirt_network,
+            'net_libvirt_vm_network': net_libvirt_vm_network,
         }

ansible/group_vars/all/seed-vm

@@ -31,10 +31,6 @@ seed_vm_data_volume:
   capacity: "{{ seed_vm_data_capacity }}"
   format: "{{ seed_vm_data_format }}"
 
-# List of network interfaces.
-seed_vm_interfaces:
-  - network: default
-
 # Name of the storage pool for the seed VM volumes.
 seed_vm_pool: default
 

ansible/seed-vm.yml

@@ -25,7 +25,7 @@
       copy:
         content: |
           #!/bin/bash
-          {% for interface in seed_hostvars.seed_vm_interfaces | map(attribute='net_name') | map('net_interface', seed_host) %}
+          {% for interface in seed_hostvars.network_interfaces | map('net_interface', seed_host) %}
           ifup {{ interface }}
           {% endfor %}
         dest: "{{ seed_user_data_path }}"
@@ -46,8 +46,7 @@
         search: "{{ seed_hostvars.resolv_search | default }}"
         dns: "{{ seed_hostvars.resolv_nameservers | default([]) }}"
       configdrive_network_device_list: >
-        {{ seed_hostvars.seed_vm_interfaces |
-           map(attribute='net_name') |
+        {{ seed_hostvars.network_interfaces |
            map('net_configdrive_network_device', seed_host) |
            list }}
       configdrive_config_user_data_path: "{{ seed_user_data_path }}"
@@ -99,7 +98,8 @@
       libvirt_vm_memory_mb: "{{ seed_hostvars.seed_vm_memory_mb }}"
       libvirt_vm_vcpus: "{{ seed_hostvars.seed_vm_vcpus }}"
       libvirt_vm_volumes: "{{ seed_hostvars.seed_vm_volumes + [seed_vm_configdrive_volume] }}"
-      libvirt_vm_interfaces: "{{ seed_hostvars.seed_vm_interfaces }}"
+      libvirt_vm_interfaces: >
+        {{ seed_hostvars.network_interfaces | map('net_libvirt_vm_network') | list }}
       libvirt_vm_image_cache_path: "{{ image_cache_path }}"
       become: True
 

doc/source/configuration.rst

@@ -147,6 +147,9 @@ supported:
     List of static IP routes. Each item should be a dict containing the
     items ``cidr`` and ``gateway``. ``cidr`` is the CIDR representation of the
     route's destination. ``gateway`` is the IP address of the next hop.
+``libvirt_network_name``
+    A name to give to a Libvirt network representing this network on the seed
+    hypervisor.
 
 IP addresses are allocated automatically by Kayobe from the
 allocation pool

etc/kayobe/seed-vm.yml

@@ -14,9 +14,6 @@
 # List of volumes.
 #seed_vm_volumes:
 
-# List of network interfaces.
-#seed_vm_interfaces:
-
 # Name of the storage pool for the seed VM volumes.
 #seed_vm_pool: