Get DNS domain for nova metadata

Get the DNS domain for the dhcp_domain setting for nova metadata over
the cloud-compute relation from nova-cloud-controller.

Fixes Bug #1805645 when using provider networks with no network node.

Change-Id: Iaba14e6939ab5d488c6299ce5cb33e26f757cf95
Partial-Bug: #1805645

hooks/nova_compute_context.py

@@ -568,6 +568,10 @@ class CloudComputeContext(context.OSContextGenerator):
                     'neutron_plugin': _neutron_plugin(),
                     'neutron_url': url,
                 }
+                # DNS domain is optional
+                dns_domain = relation_get('dns_domain', **rel)
+                if dns_domain:
+                    neutron_ctxt['dns_domain'] = dns_domain
                 admin_domain = relation_get('admin_domain_name', **rel)
                 if admin_domain:
                     neutron_ctxt['neutron_admin_domain_name'] = admin_domain
@@ -678,6 +682,8 @@ class CloudComputeContext(context.OSContextGenerator):
                 ctxt['auth_host'] = net_manager.get('keystone_host')
                 ctxt['auth_port'] = net_manager.get('auth_port')
                 ctxt['api_version'] = net_manager.get('api_version')
+                if net_manager.get('dns_domain'):
+                    ctxt['dns_domain'] = net_manager.get('dns_domain')
                 if net_manager.get('neutron_admin_domain_name'):
                     ctxt['admin_domain_name'] = net_manager.get(
                         'neutron_admin_domain_name')

templates/queens/nova.conf

@@ -25,6 +25,12 @@ default_log_levels = "amqp=WARN, amqplib=WARN, boto=WARN, qpid=WARN, sqlalchemy=
 transport_url = {{ transport_url }}
 {% endif %}
 
+{% if dns_domain -%}
+# Per LP#1805645, dhcp_domain needs to be configured for nova-metadata-api
+# It gets this information from neutron.
+dhcp_domain = {{ dns_domain }}
+{% endif -%}
+
 {% if arch == 'aarch64' -%}
 libvirt_use_virtio_for_bridges=False
 libvirt_disk_prefix=vd

templates/rocky/nova.conf

@@ -25,6 +25,12 @@ default_log_levels = "amqp=WARN, amqplib=WARN, boto=WARN, qpid=WARN, sqlalchemy=
 transport_url = {{ transport_url }}
 {% endif %}
 
+{% if dns_domain -%}
+# Per LP#1805645, dhcp_domain needs to be configured for nova-metadata-api
+# It gets this information from neutron.
+dhcp_domain = {{ dns_domain }}
+{% endif -%}
+
 {% if arch == 'aarch64' -%}
 libvirt_use_virtio_for_bridges=False
 libvirt_disk_prefix=vd

templates/stein/nova.conf

@@ -29,6 +29,12 @@ default_log_levels = "amqp=WARN, amqplib=WARN, boto=WARN, qpid=WARN, sqlalchemy=
 transport_url = {{ transport_url }}
 {% endif %}
 
+{% if dns_domain -%}
+# Per LP#1805645, dhcp_domain needs to be configured for nova-metadata-api
+# It gets this information from neutron.
+dhcp_domain = {{ dns_domain }}
+{% endif -%}
+
 {% if arch == 'aarch64' -%}
 libvirt_use_virtio_for_bridges=False
 libvirt_disk_prefix=vd

templates/train/nova.conf

@@ -32,6 +32,12 @@ default_log_levels = "amqp=WARN, amqplib=WARN, boto=WARN, qpid=WARN, sqlalchemy=
 transport_url = {{ transport_url }}
 {% endif %}
 
+{% if dns_domain -%}
+# Per LP#1805645, dhcp_domain needs to be configured for nova-metadata-api
+# It gets this information from neutron.
+dhcp_domain = {{ dns_domain }}
+{% endif -%}
+
 {% if arch == 'aarch64' -%}
 libvirt_use_virtio_for_bridges=False
 libvirt_disk_prefix=vd

unit_tests/test_nova_compute_contexts.py

@@ -239,6 +239,56 @@ class NovaComputeContextTests(CharmTestCase):
         self._save_flag_file.assert_called_with(
             path='/etc/nova/nm.conf', data='neutron')
 
+    @patch.object(context, '_neutron_plugin')
+    @patch.object(context, '_neutron_url')
+    @patch.object(context, '_network_manager')
+    def test_cloud_compute_neutron_ctxt_dns_domain(self, netman, url, plugin):
+        self.relation_ids.return_value = 'cloud-compute:0'
+        self.related_units.return_value = 'nova-cloud-controller/0'
+        netman.return_value = 'neutron'
+        plugin.return_value = 'ovs'
+        url.return_value = 'http://nova-c-c:9696'
+        NEUTRON_CONTEXT.update({'dns_domain': 'example.tld'})
+        self.test_relation.set(NEUTRON_CONTEXT)
+        cloud_compute = context.CloudComputeContext()
+        ex_ctxt = {
+            'network_manager': 'neutron',
+            'network_manager_config': {
+                'api_version': '2.0',
+                'auth_protocol': 'https',
+                'service_protocol': 'http',
+                'auth_port': '5000',
+                'dns_domain': 'example.tld',
+                'keystone_host': 'keystone_host',
+                'neutron_admin_auth_url': 'https://keystone_host:5000/v2.0',
+                'neutron_admin_password': 'openstack',
+                'neutron_admin_tenant_name': 'admin',
+                'neutron_admin_username': 'admin',
+                'neutron_admin_domain_name': 'admin_domain',
+                'neutron_auth_strategy': 'keystone',
+                'neutron_plugin': 'ovs',
+                'neutron_security_groups': True,
+                'neutron_url': 'http://nova-c-c:9696',
+                'service_protocol': 'http',
+                'service_port': '5000',
+            },
+            'service_host': 'keystone_host',
+            'admin_tenant_name': 'admin',
+            'admin_user': 'admin',
+            'admin_password': 'openstack',
+            'admin_domain_name': 'admin_domain',
+            'auth_port': '5000',
+            'auth_protocol': 'https',
+            'auth_host': 'keystone_host',
+            'api_version': '2.0',
+            'dns_domain': 'example.tld',
+            'service_protocol': 'http',
+            'service_port': '5000',
+        }
+        self.assertEqual(ex_ctxt, cloud_compute())
+        self._save_flag_file.assert_called_with(
+            path='/etc/nova/nm.conf', data='neutron')
+
     @patch.object(context, '_network_manager')
     @patch.object(context, '_neutron_plugin')
     def test_neutron_plugin_context_no_setting(self, plugin, nm):