94b961f179
After the implementation of [1], the calculation of the port's dns_assignment attribute changed for some use cases of the Neutron integration with an external DNS service. This change updates the documentation accordingly [1] https://specs.openstack.org/openstack/neutron-specs/specs/victoria/port_dns_assignment.html Partial-Bug: #1956632 Change-Id: I1c8c6850faa7741afabe31889cdad0228a366310
18 KiB
DNS integration
This page serves as a guide for how to use the DNS integration functionality of the Networking service and its interaction with the Compute service.
The integration of the Networking service with an external DNSaaS
(DNS-as-a-Service) is described in config-dns-int-ext-serv.
Users can control the behavior of the Networking service in regards to DNS using two attributes associated with ports, networks, and floating IPs. The following table shows the attributes available for each one of these resources:
| Resource | dns_name | dns_domain |
|---|---|---|
| Ports | Yes | Yes |
| Networks | No | Yes |
| Floating IPs | Yes | Yes |
Note
The DNS Integration extension enables all the attribute
and resource combinations shown in the previous table, except for
dns_domain for ports, which requires the
dns_domain for ports extension.
Note
Since the DNS Integration extension is a subset of
dns_domain for ports, if dns_domain
functionality for ports is required, only the latter extension has to be
configured.
Note
When the dns_domain for ports extension is configured,
DNS Integration is also included when the Neutron server
responds to a request to list the active API extensions. This preserves
backwards API compatibility.
The Networking service internal DNS resolution
The Networking service enables users to control the name assigned to ports by the internal DNS. To enable this functionality, do the following:
Edit the
/etc/neutron/neutron.conffile and assign a value different toopenstacklocal(its default value) to thedns_domainparameter in the[default]section. As an example:dns_domain = example.org.Add
dns(for theDNS Integrationextension) ordns_domain_ports(for thedns_domain for portsextension) toextension_driversin the[ml2]section of/etc/neutron/plugins/ml2/ml2_conf.ini. The following is an example:[ml2] extension_drivers = port_security,dns_domain_ports
After re-starting the neutron-server, users will be able
to assign a dns_name attribute to their ports.
Note
The enablement of this functionality is prerequisite for the
enablement of the Networking service integration with an external DNS
service, which is described in detail in config-dns-int-ext-serv.
The following illustrates the creation of a port with
my-port in its dns_name attribute.
Note
The name assigned to the port by the Networking service internal DNS
is now visible in the response in the dns_assignment
attribute.
$ openstack port create --network my-net --dns-name my-port test
+-----------------------+-------------------------------------------------------------------------------+
| Field | Value |
+-----------------------+-------------------------------------------------------------------------------+
| admin_state_up | UP |
| allowed_address_pairs | |
| binding_host_id | |
| binding_profile | |
| binding_vif_details | |
| binding_vif_type | unbound |
| binding_vnic_type | normal |
| created_at | 2016-02-05T21:35:04Z |
| data_plane_status | None |
| description | |
| device_id | |
| device_owner | |
| dns_assignment | fqdn='my-port.example.org.', hostname='my-port', ip_address='192.0.2.67' |
| dns_domain | None |
| dns_name | my-port |
| extra_dhcp_opts | |
| fixed_ips | ip_address='192.0.2.67', subnet_id='6141b474-56cd-430f-b731-71660bb79b79' |
| id | fb3c10f4-017e-420c-9be1-8f8c557ae21f |
| mac_address | fa:16:3e:aa:9b:e1 |
| name | test |
| network_id | bf2802a0-99a0-4e8c-91e4-107d03f158ea |
| port_security_enabled | True |
| project_id | d5660cb1e6934612a01b4fb2fb630725 |
| qos_policy_id | None |
| revision_number | 1 |
| security_group_ids | 1f0ddd73-7e3c-48bd-a64c-7ded4fe0e635 |
| status | DOWN |
| tags | |
| trunk_details | None |
| updated_at | 2016-02-05T21:35:04Z |
+-----------------------+-------------------------------------------------------------------------------+When this functionality is enabled, it is leveraged by the Compute
service when creating instances. When allocating ports for an instance
during boot, the Compute service populates the dns_name
attributes of these ports with the hostname attribute of
the instance, which is a DNS sanitized version of its display name. As a
consequence, at the end of the boot process, the allocated ports will be
known in the dnsmasq associated to their networks by their instance
hostname.
The following is an example of an instance creation, showing how its
hostname populates the dns_name attribute of
the allocated port:
$ openstack server create --image cirros --flavor 42 \
--nic net-id=37aaff3a-6047-45ac-bf4f-a825e56fd2b3 my_vm
+--------------------------------------+----------------------------------------------------------------+
| Field | Value |
+--------------------------------------+----------------------------------------------------------------+
| OS-DCF:diskConfig | MANUAL |
| OS-EXT-AZ:availability_zone | |
| OS-EXT-STS:power_state | 0 |
| OS-EXT-STS:task_state | scheduling |
| OS-EXT-STS:vm_state | building |
| OS-SRV-USG:launched_at | - |
| OS-SRV-USG:terminated_at | - |
| accessIPv4 | |
| accessIPv6 | |
| adminPass | dB45Zvo8Jpfe |
| config_drive | |
| created | 2016-02-05T21:35:04Z |
| flavor | m1.nano (42) |
| hostId | |
| id | 66c13cb4-3002-4ab3-8400-7efc2659c363 |
| image | cirros-0.3.5-x86_64-uec(b9d981eb-d21c-4ce2-9dbc-dd38f3d9015f) |
| key_name | - |
| locked | False |
| metadata | {} |
| name | my_vm |
| os-extended-volumes:volumes_attached | [] |
| progress | 0 |
| security_groups | default |
| status | BUILD |
| tenant_id | d5660cb1e6934612a01b4fb2fb630725 |
| updated | 2016-02-05T21:35:04Z |
| user_id | 8bb6e578cba24e7db9d3810633124525 |
+--------------------------------------+----------------------------------------------------------------+
$ openstack port list --device-id 66c13cb4-3002-4ab3-8400-7efc2659c363
+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------------+--------+
| ID | Name | MAC Address | Fixed IP Addresses | Status |
+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------------+--------+
| b3ecc464-1263-44a7-8c38-2d8a52751773 | | fa:16:3e:a8:ce:b8 | ip_address='203.0.113.8', subnet_id='277eca5d-9869-474b-960e-6da5951d09f7' | ACTIVE |
| | | | ip_address='2001:db8:10::8', subnet_id='eab47748-3f0a-4775-a09f-b0c24bb64bc4' | |
+--------------------------------------+------+-------------------+---------------------------------------------------------------------------------------+--------+
$ openstack port show b3ecc464-1263-44a7-8c38-2d8a52751773
+-----------------------+------------------------------------------------------------------------------------------------------------+
| Field | Value |
+-----------------------+------------------------------------------------------------------------------------------------------------+
| admin_state_up | UP |
| allowed_address_pairs | |
| binding_host_id | vultr.guest |
| binding_profile | |
| binding_vif_details | datapath_type='system', ovs_hybrid_plug='True', port_filter='True' |
| binding_vif_type | ovs |
| binding_vnic_type | normal |
| created_at | 2016-02-05T21:35:04Z |
| data_plane_status | None |
| description | |
| device_id | 66c13cb4-3002-4ab3-8400-7efc2659c363 |
| device_owner | compute:None |
| dns_assignment | fqdn='my-vm.example.org.', hostname='my-vm', ip_address='203.0.113.8' |
| | fqdn='my-vm.example.org.', hostname='my-vm', ip_address='2001:db8:10::8' |
| dns_domain | example.org. |
| dns_name | my-vm |
| extra_dhcp_opts | |
| fixed_ips | ip_address='203.0.113.8', subnet_id='277eca5d-9869-474b-960e-6da5951d09f7' |
| | ip_address='2001:db8:10::8', subnet_id='eab47748-3f0a-4775-a09f-b0c24bb64bc4' |
| id | b3ecc464-1263-44a7-8c38-2d8a52751773 |
| mac_address | fa:16:3e:a8:ce:b8 |
| name | |
| network_id | 37aaff3a-6047-45ac-bf4f-a825e56fd2b3 |
| port_security_enabled | True |
| project_id | d5660cb1e6934612a01b4fb2fb630725 |
| qos_policy_id | None |
| revision_number | 1 |
| security_group_ids | 1f0ddd73-7e3c-48bd-a64c-7ded4fe0e635 |
| status | ACTIVE |
| tags | |
| trunk_details | None |
| updated_at | 2016-02-05T21:35:04Z |
+-----------------------+------------------------------------------------------------------------------------------------------------+In the above example notice that:
- The name given to the instance by the user,
my_vm, is sanitized by the Compute service and becomesmy-vmas the port'sdns_name. - The port's
dns_assignmentattribute shows that its FQDN ismy-vm.example.org.in the Networking service internal DNS, which is the result of concatenating the port'sdns_namewith the value configured in thedns_domainparameter inneutron.conf, as explained previously. - The
dns_assignmentattribute also shows that the port'shostnamein the Networking service internal DNS ismy-vm. - Instead of having the Compute service create the port for the
instance, the user might have created it and assigned a value to its
dns_nameattribute. In this case, the value assigned to thedns_nameattribute must be equal to the value that Compute service will assign to the instance'shostname, in this examplemy-vm. Otherwise, the instance boot will fail.
Note
When the Networking service integration with an external DNS service
is enabled, a port's FQDN in the dns_assignment attribute
will not be calculated as described above in some well defined cases.
For a description of these cases please see config-dns-int-ext-dns-assignment.