Using DNS with Neutron & Nova¶
Neutron can be integrated with Designate to provide automatic recordset creation for ports and, by proxy, Nova server instances. This section will describe how you can use this integration to have Designate DNS recordsets created for Neutron ports and Nova instances at creation time.
Neutron DNS Extensions¶
DNS integration in Neutron is optional and an extension must be enabled in the Neutron configuration file, by a cloud administrator, for DNS names to be assigned automatically to Neutron and Nova resources. You can check if a DNS integration extension is enabled by querying the Neutron extensions API:
$ openstack extension list --network -f value -c Alias | grep dns-integration
dns-integration
One of these extensions must be enabled to allow Neutron and, via Neutron, Nova to automatically create DNS recordsets in Designate:
dns-integration
dns-domain-ports (includes dns-integration)
subnet-dns-publish-fixed-ip (includes dns-integration and dns-domain-ports)
dns-integration-domain-keywords (includes all others)
dns-integration¶
When the dns-integration extension is enabled the following DNS attributes will be available via Neutron:
Resource |
dns_name |
dns_domain |
|---|---|---|
Ports |
Yes |
No |
Networks |
No |
Yes |
Floating IPs |
Yes |
Yes |
dns-domain-ports¶
In addition, if the dns-domain-ports extension is enabled in Neutron, ports can be created with a dns_domain specified. This dns_domain will take precedence over the dns_domain setting for the network. You can check if the dns-domain-ports extension is enabled by querying the Neutron extensions API:
$ openstack extension list --network -f value -c Alias | grep dns-domain-ports
dns-domain-ports
With the dns-domain-ports extension is enabled the following DNS settings will be available via Neutron:
Resource |
dns_name |
dns_domain |
|---|---|---|
Ports |
Yes |
Yes |
Networks |
No |
Yes |
Floating IPs |
Yes |
Yes |
Both of these extensions impose a set of criteria for when DNS recordsets will be created in Designate.
A dns_domain must be specified either on the network, port, or floating IP. If both the network and the port or floating IP specify a dns_domain, the dns_domain specified on the port or floating IP will take precedent over the dns_domain provided on the network.
The network must not have the router:external field set to True.
The network type must be one of: FLAT, VLAN, GRE, VXLAN, or GENEVE.
For VLAN, GRE, VXLAN, or GENEVE networks, the segmentation ID must be outside the ranges configured in the Neutron ml2_confg file. For example, with VXLAN networks, the range setting is [ml2_type_vxlan] vni_ranges.
The zone for the dns_domain must already exist in Designate and the project ID creating the Nova instance, port, or floating IP must have permission to create recordsets in the zone.
These restrictions typically mean that a special network will need to be created by an administrator that will allow recordsets to be created in Designate.
If these criteria are not all met, Neutron will create a DNS assignment in the Neutron internal resolvers using the default dns_domain specified in the Neutron configuration file. The current default domain is “openstacklocal.”.
Warning
If the user creating the Nova instance, port, or floating IP does not have permission to create recordsets in the zone or the zone does not exist in Designate, Neutron will create the port with the dns_assignment field populated using the dns_domain provided, but no recordset will be created in Designate. Neutron will log the error “Error publishing port data in external DNS service.”.
subnet-dns-publish-fixed-ip¶
A third Neutron extension is available called subnet-dns-publish-fixed-ip. This extension includes the capabilities of the dns-domain-ports extension, but removes the restrictions if the subnet dns_publish_fixed_ip property is set to True.
dns-integration-domain-keywords¶
The fourth Neutron extension, including the capabilities of the subnet-dns-publish-fixed-ip extension, is called dns-integration-domain-keywords. It allows the use of keywords in the dns_domain that will be replaced when a port is created. Valid keywords are: <project_id>, <project_name>, <user_id>, and <user_name>.
Note
For more information on enabling DNS integration in Neutron, see the Neutron Networking Guide.
DNS for Nova Server Instances¶
DNS integration with Neutron allows you to automatically create a DNS recordset for Nova instances. When Nova requests the Neutron port to be created for the new instance, Neutron will attempt to create a DNS recordset for the port in Designate.
As an example, we will create a new Nova instance with the DNS name of “server.example.org” registered in Designate.
Note
This example is for user created networks. DNS records can be automatically created for Nova server instances on networks created by a cloud administrator if they meet the Neutron criteria.
Steps:
Check that the subnet-dns-publish-fixed-ip Neutron extension is enabled.
Create the zone “example.org.” in Designate.
Create a network, providing the dns_domain of “example.org.”, that we will use for the Nova instance.
Create a subnet on the network with dns_publish_fixed_ip set to True.
Create the Nova instance, with name “server” and a NIC on the network.
Note
The DNS domain must always be a Fully Qualified Domain Name (FQDN), meaning it will always end with a period.
CLI Commands:
$ openstack extension list --network -f value -c Alias | grep subnet-dns-publish-fixed-ip
$ openstack zone create --email example@example.org example.org.
$ openstack network create --dns-domain example.org. example-net
$ openstack subnet create --allocation-pool start=192.0.2.10,end=192.0.2.200 --network example-net --subnet-range 192.0.2.0/24 --dns-publish-fixed-ip example-subnet
$ openstack server create --image cirros-0.5.2-x86_64-disk --flavor 1 --nic net-id=example-net server
$ openstack recordset list --type A example.org.
+---------------+---------------------+------+------------+--------+--------+
| id | name | type | records | status | action |
+---------------+---------------------+------+------------+--------+--------+
| 7b8d1be6-1b23 | server.example.org. | A | 192.0.2.44 | ACTIVE | NONE |
| -478a-94d5-60 | | | | | |
| b876dca2c8 | | | | | |
+---------------+---------------------+------+------------+--------+--------+
DNS for Neutron Ports¶
DNS integration with Neutron allows you to automatically create a DNS recordset for Neutron ports.
As an example, we will create a new Neutron port with the DNS name of “example-port.example.org” registered in Designate.
Note
This example is for user created networks. DNS records can be automatically created for Neutron ports on networks created by a cloud administrator if they meet the Neutron criteria.
Steps:
Check that the subnet-dns-publish-fixed-ip Neutron extension is enabled.
Create the zone “example.org.” in Designate.
Create a network, providing the dns_domain of “example.org.”, that we will use for the Neutron port.
Create a subnet on the network with dns_publish_fixed_ip set to True.
Create the Neutron port specifying the dns_name of “example-port” for the port.
Note
The DNS domain must always be a Fully Qualified Domain Name (FQDN), meaning it will always end with a period.
CLI Commands:
$ openstack extension list --network -f value -c Alias | grep subnet-dns-publish-fixed-ip
$ openstack zone create --email example@example.org example.org.
$ openstack network create --dns-domain example.org. example-net
$ openstack subnet create --allocation-pool start=192.0.2.10,end=192.0.2.200 --network example-net --subnet-range 192.0.2.0/24 --dns-publish-fixed-ip example-subnet
$ openstack port create --network example-net --dns-name example-port my-example-port
$ openstack recordset list --type A example.org.
+---------------+---------------------------+------+-------------+--------+--------+
| id | name | type | records | status | action |
+---------------+---------------------------+------+-------------+--------+--------+
| 9ebbe94f-2442 | example-port.example.org. | A | 192.0.2.149 | ACTIVE | NONE |
| -4bb8-9cfa-6d | | | | | |
| ca1daba73f | | | | | |
+---------------+---------------------------+------+------------+--------+--------+
DNS for Floating IPs¶
DNS integration with Neutron allows you to automatically create a DNS recordset for Neutron floating IP addresses.
As an example, we will create a new Neutron floating IP with the DNS name of “example-fip.example.org” registered in Designate.
Steps:
Create the Neutron floating IP specifying the dns_name of “example-fip” and the dns_domain as “example.org.”.
Note
The DNS domain must always be a Fully Qualified Domain Name (FQDN), meaning it will always end with a period.
CLI Commands:
$ openstack floating ip create --dns-name example-fip --dns-domain example.org. example-net
$ openstack recordset list --type A example.org.
+---------------+--------------------------+------+-------------+--------+--------+
| id | name | type | records | status | action |
+---------------+--------------------------+------+-------------+--------+--------+
| e1eca823-169d | example-fip.example.org. | A | 192.0.2.106 | ACTIVE | NONE |
| -4d0a-975e-91 | | | | | |
| a9907ec0c1 | | | | | |
+---------------+--------------------------+------+------------+--------+--------+
