DNS HA

Implement DNS high availability. Pass the correct information to
hacluster to register a DNS entry with MAAS 2.0 or greater rather
than using a virtual IP.

Charm-helpers sync to bring in DNS HA helpers

Change-Id: Icc9bfb16e07ca6cf5475182b1974b09949cd89b6

README.md

@@ -58,27 +58,41 @@ have already deployed Ceph using the ceph charm:
 This configuration can also be used to support Glance in HA/Scale-out
 deployments.
 
-Glance HA/Scale-out
+HA/Clustering
 ===================
 
-The Glance charm can also be used in a HA/scale-out configuration using
+There are two mutually exclusive high availability options: using virtual
-the hacluster charm:
+IP(s) or DNS. In both cases, a relationship to hacluster is required which
+provides the corosync back end HA functionality.
 
-    juju deploy -n 3 glance
+To use virtual IP(s) the clustered nodes must be on the same subnet such that
-    juju deploy hacluster haglance
+the VIP is a valid IP on the subnet for one of the node's interfaces and each
-    juju set glance vip=<virtual IP address to access glance over>
+node has an interface in said subnet. The VIP becomes a highly-available API
-    juju add-relation glance haglance
+endpoint.
-    juju add-relation glance mysql
-    juju add-relation glance keystone
-    juju add-relation glance nova-cloud-controller
-    juju add-relation glance ceph|swift-proxy
 
-In this configuration, 3 service units host the Glance image service;
+At a minimum, the config option 'vip' must be set in order to use virtual IP
-API requests are load balanced across all 3 service units via the
+HA. If multiple networks are being used, a VIP should be provided for each
-configured virtual IP address (which is also registered into Keystone
+network, separated by spaces. Optionally, vip_iface or vip_cidr may be
-as the endpoint for Glance).
+specified.
 
-Note that Glance in this configuration must be used with either Ceph or
+To use DNS high availability there are several prerequisites. However, DNS HA
+does not require the clustered nodes to be on the same subnet.
+Currently the DNS HA feature is only available for MAAS 2.0 or greater
+environments. MAAS 2.0 requires Juju 2.0 or greater. The clustered nodes must
+have static or "reserved" IP addresses registered in MAAS. The DNS hostname(s)
+must be pre-registered in MAAS before use with DNS HA.
+
+At a minimum, the config option 'dns-ha' must be set to true and at least one
+of 'os-public-hostname', 'os-internal-hostname' or 'os-internal-hostname' must
+be set in order to use DNS HA. One or more of the above hostnames may be set.
+
+The charm will throw an exception in the following circumstances:
+If neither 'vip' nor 'dns-ha' is set and the charm is related to hacluster
+If both 'vip' and 'dns-ha' are set as they are mutually exclusive
+If 'dns-ha' is set and none of the os-{admin,internal,public}-hostname(s) are
+set
+
+Note that Glance in HA configuration must be used with either Ceph or
 Swift providing backing image storage.
 
 Glance metering

charmhelpers/contrib/hahelpers/cluster.py

@@ -280,14 +280,14 @@ def get_hacluster_config(exclude_keys=None):
     for initiating a relation to hacluster:
 
         ha-bindiface, ha-mcastport, vip, os-internal-hostname,
-        os-admin-hostname, os-public-hostname
+        os-admin-hostname, os-public-hostname, os-access-hostname
 
     param: exclude_keys: list of setting key(s) to be excluded.
     returns: dict: A dict containing settings keyed by setting name.
     raises: HAIncompleteConfig if settings are missing or incorrect.
     '''
     settings = ['ha-bindiface', 'ha-mcastport', 'vip', 'os-internal-hostname',
-                'os-admin-hostname', 'os-public-hostname']
+                'os-admin-hostname', 'os-public-hostname', 'os-access-hostname']
     conf = {}
     for setting in settings:
         if exclude_keys and setting in exclude_keys:
@@ -324,7 +324,7 @@ def valid_hacluster_config():
     # If dns-ha then one of os-*-hostname must be set
     if dns:
         dns_settings = ['os-internal-hostname', 'os-admin-hostname',
-                        'os-public-hostname']
+                        'os-public-hostname', 'os-access-hostname']
         # At this point it is unknown if one or all of the possible
         # network spaces are in HA. Validate at least one is set which is
         # the minimum required.

charmhelpers/contrib/openstack/ha/utils.py

@@ -36,6 +36,10 @@ from charmhelpers.core.hookenv import (
     DEBUG,
 )
 
+from charmhelpers.core.host import (
+    lsb_release
+)
+
 from charmhelpers.contrib.openstack.ip import (
     resolve_address,
 )
@@ -63,8 +67,11 @@ def update_dns_ha_resource_params(resources, resource_params,
                     DNS HA
     """
 
+    # Validate the charm environment for DNS HA
+    assert_charm_supports_dns_ha()
+
     settings = ['os-admin-hostname', 'os-internal-hostname',
-                'os-public-hostname']
+                'os-public-hostname', 'os-access-hostname']
 
     # Check which DNS settings are set and update dictionaries
     hostname_group = []
@@ -109,3 +116,15 @@ def update_dns_ha_resource_params(resources, resource_params,
         msg = 'DNS HA: Hostname group has no members.'
         status_set('blocked', msg)
         raise DNSHAException(msg)
+
+
+def assert_charm_supports_dns_ha():
+    """Validate prerequisites for DNS HA
+    The MAAS client is only available on Xenial or greater
+    """
+    if lsb_release().get('DISTRIB_RELEASE') < '16.04':
+        msg = ('DNS HA is only supported on 16.04 and greater '
+               'versions of Ubuntu.')
+        status_set('blocked', msg)
+        raise DNSHAException(msg)
+    return True

charmhelpers/contrib/openstack/utils.py

@@ -725,15 +725,14 @@ def git_install_requested():
 requirements_dir = None
 
 
-def git_default_repos(projects_yaml):
+def git_default_repos(projects):
     """
     Returns default repos if a default openstack-origin-git value is specified.
     """
     service = service_name()
-    core_project = service
 
     for default, branch in GIT_DEFAULT_BRANCHES.iteritems():
-        if projects_yaml == default:
+        if projects == default:
 
             # add the requirements repo first
             repo = {
@@ -743,41 +742,34 @@ def git_default_repos(projects_yaml):
             }
             repos = [repo]
 
-            # neutron-* and nova-* charms require some additional repos
+            # neutron and nova charms require some additional repos
-            if service in ['neutron-api', 'neutron-gateway',
+            if service == 'neutron':
-                           'neutron-openvswitch']:
+                for svc in ['neutron-fwaas', 'neutron-lbaas', 'neutron-vpnaas']:
-                core_project = 'neutron'
-                for project in ['neutron-fwaas', 'neutron-lbaas',
-                                'neutron-vpnaas']:
                     repo = {
-                        'name': project,
+                        'name': svc,
-                        'repository': GIT_DEFAULT_REPOS[project],
+                        'repository': GIT_DEFAULT_REPOS[svc],
                         'branch': branch,
                     }
                     repos.append(repo)
-
+            elif service == 'nova':
-            elif service in ['nova-cloud-controller', 'nova-compute']:
-                core_project = 'nova'
                 repo = {
                     'name': 'neutron',
                     'repository': GIT_DEFAULT_REPOS['neutron'],
                     'branch': branch,
                 }
                 repos.append(repo)
-            elif service == 'openstack-dashboard':
-                core_project = 'horizon'
 
-            # finally add the current service's core project repo
+            # finally add the current service's repo
             repo = {
-                'name': core_project,
+                'name': service,
-                'repository': GIT_DEFAULT_REPOS[core_project],
+                'repository': GIT_DEFAULT_REPOS[service],
                 'branch': branch,
             }
             repos.append(repo)
 
             return yaml.dump(dict(repositories=repos))
 
-    return projects_yaml
+    return projects
 
 
 def _git_yaml_load(projects_yaml):

config.yaml

@@ -112,6 +112,12 @@ options:
       effect (although it can be changed in ceph by manually configuring
       your ceph cluster).
   # HA configuration settings
+  dns-ha:
+    type: boolean
+    default: False
+    description: |
+        Use DNS HA with MAAS 2.0. Note if this is set do not set vip
+        settings below.
   vip:
     type: string
     default:
@@ -232,6 +238,30 @@ options:
       create a public endpoint for glance of:
       .
       https://glance.example.com:9292/
+  os-internal-hostname:
+    type: string
+    default:
+    description: |
+      The hostname or address of the internal endpoints created for glance
+      in the keystone identity provider.
+      .
+      This value will be used for internal endpoints. For example, an
+      os-internal-hostname set to 'glance.internal.example.com' with ssl enabled will
+      create a internal endpoint for glance of:
+      .
+      https://glance.internal.example.com:9292/
+  os-admin-hostname:
+    type: string
+    default:
+    description: |
+      The hostname or address of the admin endpoints created for glance
+      in the keystone identity provider.
+      .
+      This value will be used for admin endpoints. For example, an
+      os-admin-hostname set to 'glance.admin.example.com' with ssl enabled will
+      create a admin endpoint for glance of:
+      .
+      https://glance.admin.example.com:9292/
   prefer-ipv6:
     type: boolean
     default: False

hooks/glance_relations.py

@@ -60,6 +60,9 @@ from charmhelpers.contrib.hahelpers.cluster import (
     is_elected_leader,
     get_hacluster_config
 )
+from charmhelpers.contrib.openstack.ha.utils import (
+    update_dns_ha_resource_params,
+)
 from charmhelpers.contrib.openstack.utils import (
     config_value_changed,
     configure_installation_source,
@@ -437,6 +440,11 @@ def ha_relation_joined(relation_id=None):
         'res_glance_haproxy': 'op monitor interval="5s"'
     }
 
+    if config('dns-ha'):
+        update_dns_ha_resource_params(relation_id=relation_id,
+                                      resources=resources,
+                                      resource_params=resource_params)
+    else:
         vip_group = []
         for vip in cluster_config['vip'].split():
             if is_ipv6(vip):

unit_tests/test_glance_relations.py

@@ -55,6 +55,8 @@ TO_PATCH = [
     'configure_installation_source',
     'os_release',
     'openstack_upgrade_available',
+    # charmhelpers.contrib.openstack.ha.utils
+    'update_dns_ha_resource_params',
     # charmhelpers.contrib.hahelpers.cluster_utils
     'is_elected_leader',
     # hooks.glance_utils
@@ -765,6 +767,41 @@ class GlanceRelationTests(CharmTestCase):
         }
         self.relation_set.assert_called_with(**args)
 
+    def test_ha_joined_dns_ha(self):
+        def _fake_update(resources, resource_params, relation_id=None):
+            resources.update({'res_glance_public_hostname': 'ocf:maas:dns'})
+            resource_params.update({'res_glance_public_hostname':
+                                    'params fqdn="keystone.maas" '
+                                    'ip_address="10.0.0.1"'})
+
+        self.test_config.set('dns-ha', True)
+        self.get_hacluster_config.return_value = {
+            'vip': None,
+            'ha-bindiface': 'em0',
+            'ha-mcastport': '8080',
+            'os-admin-hostname': None,
+            'os-internal-hostname': None,
+            'os-public-hostname': 'keystone.maas',
+        }
+        args = {
+            'relation_id': None,
+            'corosync_bindiface': 'em0',
+            'corosync_mcastport': '8080',
+            'init_services': {'res_glance_haproxy': 'haproxy'},
+            'resources': {'res_glance_public_hostname': 'ocf:maas:dns',
+                          'res_glance_haproxy': 'lsb:haproxy'},
+            'resource_params': {
+                'res_glance_public_hostname': 'params fqdn="keystone.maas" '
+                                              'ip_address="10.0.0.1"',
+                'res_glance_haproxy': 'op monitor interval="5s"'},
+            'clones': {'cl_glance_haproxy': 'res_glance_haproxy'}
+        }
+        self.update_dns_ha_resource_params.side_effect = _fake_update
+
+        relations.ha_relation_joined()
+        self.assertTrue(self.update_dns_ha_resource_params.called)
+        self.relation_set.assert_called_with(**args)
+
     def test_ha_relation_changed_not_clustered(self):
         self.relation_get.return_value = False
         relations.ha_relation_changed()