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: I62bb49fbaebdd3c787f96f4b6ad107f8e3e368a7

.gitignore

@@ -8,3 +8,4 @@ tags
 joined-string
 .unit-state.db
 trusty/**
+xenial/

README.md

@@ -61,8 +61,35 @@ credentials exist (as configured via charm configuration)
 HA/Clustering
 -------------
 
-VIP is only required if you plan on multi-unit clustering (requires relating
-with hacluster charm). The VIP becomes a highly-available API endpoint.
+There are two mutually exclusive high availability options: using virtual
+IP(s) or DNS. In both cases, a relationship to hacluster is required which
+provides the corosync back end HA functionality.
+
+To use virtual IP(s) the clustered nodes must be on the same subnet such that
+the VIP is a valid IP on the subnet for one of the node's interfaces and each
+node has an interface in said subnet. The VIP becomes a highly-available API
+endpoint.
+
+At a minimum, the config option 'vip' must be set in order to use virtual IP
+HA. If multiple networks are being used, a VIP should be provided for each
+network, separated by spaces. Optionally, vip_iface or vip_cidr may be
+specified.
+
+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
 
 SSL/HTTPS
 ---------

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

@@ -0,0 +1,130 @@
+# Copyright 2014-2016 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+#
+# Copyright 2016 Canonical Ltd.
+#
+# Authors:
+#  Openstack Charmers <
+#
+
+"""
+Helpers for high availability.
+"""
+
+import re
+
+from charmhelpers.core.hookenv import (
+    log,
+    relation_set,
+    charm_name,
+    config,
+    status_set,
+    DEBUG,
+)
+
+from charmhelpers.core.host import (
+    lsb_release
+)
+
+from charmhelpers.contrib.openstack.ip import (
+    resolve_address,
+)
+
+
+class DNSHAException(Exception):
+    """Raised when an error occurs setting up DNS HA
+    """
+
+    pass
+
+
+def update_dns_ha_resource_params(resources, resource_params,
+                                  relation_id=None,
+                                  crm_ocf='ocf:maas:dns'):
+    """ Check for os-*-hostname settings and update resource dictionaries for
+    the HA relation.
+
+    @param resources: Pointer to dictionary of resources.
+                      Usually instantiated in ha_joined().
+    @param resource_params: Pointer to dictionary of resource parameters.
+                            Usually instantiated in ha_joined()
+    @param relation_id: Relation ID of the ha relation
+    @param crm_ocf: Corosync Open Cluster Framework resource agent to use for
+                    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-access-hostname']
+
+    # Check which DNS settings are set and update dictionaries
+    hostname_group = []
+    for setting in settings:
+        hostname = config(setting)
+        if hostname is None:
+            log('DNS HA: Hostname setting {} is None. Ignoring.'
+                ''.format(setting),
+                DEBUG)
+            continue
+        m = re.search('os-(.+?)-hostname', setting)
+        if m:
+            networkspace = m.group(1)
+        else:
+            msg = ('Unexpected DNS hostname setting: {}. '
+                   'Cannot determine network space name'
+                   ''.format(setting))
+            status_set('blocked', msg)
+            raise DNSHAException(msg)
+
+        hostname_key = 'res_{}_{}_hostname'.format(charm_name(), networkspace)
+        if hostname_key in hostname_group:
+            log('DNS HA: Resource {}: {} already exists in '
+                'hostname group - skipping'.format(hostname_key, hostname),
+                DEBUG)
+            continue
+
+        hostname_group.append(hostname_key)
+        resources[hostname_key] = crm_ocf
+        resource_params[hostname_key] = (
+            'params fqdn="{}" ip_address="{}" '
+            ''.format(hostname, resolve_address(endpoint_type=networkspace,
+                                                override=False)))
+
+    if len(hostname_group) >= 1:
+        log('DNS HA: Hostname group is set with {} as members. '
+            'Informing the ha relation'.format(' '.join(hostname_group)),
+            DEBUG)
+        relation_set(relation_id=relation_id, groups={
+            'grp_{}_hostnames'.format(charm_name()): ' '.join(hostname_group)})
+    else:
+        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
-            if service in ['neutron-api', 'neutron-gateway',
-                           'neutron-openvswitch']:
-                core_project = 'neutron'
-                for project in ['neutron-fwaas', 'neutron-lbaas',
-                                'neutron-vpnaas']:
+            # neutron and nova charms require some additional repos
+            if service == 'neutron':
+                for svc in ['neutron-fwaas', 'neutron-lbaas', 'neutron-vpnaas']:
                     repo = {
-                        'name': project,
-                        'repository': GIT_DEFAULT_REPOS[project],
+                        'name': svc,
+                        'repository': GIT_DEFAULT_REPOS[svc],
                         'branch': branch,
                     }
                     repos.append(repo)
-
-            elif service in ['nova-cloud-controller', 'nova-compute']:
-                core_project = 'nova'
+            elif service == '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,
-                'repository': GIT_DEFAULT_REPOS[core_project],
+                'name': service,
+                '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):

charmhelpers/fetch/__init__.py

@@ -398,16 +398,13 @@ def install_remote(source, *args, **kwargs):
     # We ONLY check for True here because can_handle may return a string
     # explaining why it can't handle a given source.
     handlers = [h for h in plugins() if h.can_handle(source) is True]
-    installed_to = None
     for handler in handlers:
         try:
-            installed_to = handler.install(source, *args, **kwargs)
+            return handler.install(source, *args, **kwargs)
         except UnhandledSource as e:
             log('Install source attempt unsuccessful: {}'.format(e),
                 level='WARNING')
-    if not installed_to:
-        raise UnhandledSource("No handler found for source {}".format(source))
-    return installed_to
+    raise UnhandledSource("No handler found for source {}".format(source))
 
 
 def install_from_config(config_var_name):

charmhelpers/fetch/bzrurl.py

@@ -42,15 +42,23 @@ class BzrUrlFetchHandler(BaseFetchHandler):
         else:
             return True
 
-    def branch(self, source, dest):
+    def branch(self, source, dest, revno=None):
         if not self.can_handle(source):
             raise UnhandledSource("Cannot handle {}".format(source))
+        cmd_opts = []
+        if revno:
+            cmd_opts += ['-r', str(revno)]
         if os.path.exists(dest):
-            check_call(['bzr', 'pull', '--overwrite', '-d', dest, source])
+            cmd = ['bzr', 'pull']
+            cmd += cmd_opts
+            cmd += ['--overwrite', '-d', dest, source]
         else:
-            check_call(['bzr', 'branch', source, dest])
+            cmd = ['bzr', 'branch']
+            cmd += cmd_opts
+            cmd += [source, dest]
+        check_call(cmd)
 
-    def install(self, source, dest=None):
+    def install(self, source, dest=None, revno=None):
         url_parts = self.parse_url(source)
         branch_name = url_parts.path.strip("/").split("/")[-1]
         if dest:
@@ -59,10 +67,11 @@ class BzrUrlFetchHandler(BaseFetchHandler):
             dest_dir = os.path.join(os.environ.get('CHARM_DIR'), "fetched",
                                     branch_name)
 
-        if not os.path.exists(dest_dir):
-            mkdir(dest_dir, perms=0o755)
+        if dest and not os.path.exists(dest):
+            mkdir(dest, perms=0o755)
+
         try:
-            self.branch(source, dest_dir)
+            self.branch(source, dest_dir, revno)
         except OSError as e:
             raise UnhandledSource(e.strerror)
         return dest_dir

config.yaml

@@ -177,6 +177,12 @@ options:
     default: True
     description: Ldap identity server backend readonly to keystone.
   # 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:
@@ -278,6 +284,30 @@ options:
       create a public endpoint for keystone as:
       .
       https://keystone.example.com:5000/v2.0
+  os-internal-hostname:
+    type: string
+    default:
+    description: |
+      The hostname or address of the internal endpoints created for keystone
+      in the keystone identity provider (itself).
+      .
+      This value will be used for internal endpoints. For example, an
+      os-internal-hostname set to 'keystone.internal.example.com' with ssl enabled will
+      create a internal endpoint for keystone as:
+      .
+      https://keystone.internal.example.com:5000/v2.0
+  os-admin-hostname:
+    type: string
+    default:
+    description: |
+      The hostname or address of the admin endpoints created for keystone
+      in the keystone identity provider (itself).
+      .
+      This value will be used for admin endpoints. For example, an
+      os-admin-hostname set to 'keystone.admin.example.com' with ssl enabled will
+      create a admin endpoint for keystone as:
+      .
+      https://keystone.admin.example.com:5000/v2.0
   prefer-ipv6:
     type: boolean
     default: False

hooks/keystone_hooks.py

@@ -106,6 +106,10 @@ from charmhelpers.contrib.hahelpers.cluster import (
     https,
 )
 
+from charmhelpers.contrib.openstack.ha.utils import (
+    update_dns_ha_resource_params,
+)
+
 from charmhelpers.payload.execd import execd_preinstall
 from charmhelpers.contrib.peerstorage import (
     peer_retrieve_by_prefix,
@@ -592,41 +596,46 @@ def ha_joined(relation_id=None):
         'res_ks_haproxy': 'op monitor interval="5s"'
     }
 
-    vip_group = []
-    for vip in cluster_config['vip'].split():
-        if is_ipv6(vip):
-            res_ks_vip = 'ocf:heartbeat:IPv6addr'
-            vip_params = 'ipv6addr'
-        else:
-            res_ks_vip = 'ocf:heartbeat:IPaddr2'
-            vip_params = 'ip'
+    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):
+                res_ks_vip = 'ocf:heartbeat:IPv6addr'
+                vip_params = 'ipv6addr'
+            else:
+                res_ks_vip = 'ocf:heartbeat:IPaddr2'
+                vip_params = 'ip'
 
-        iface = (get_iface_for_address(vip) or
-                 config('vip_iface'))
-        netmask = (get_netmask_for_address(vip) or
-                   config('vip_cidr'))
+            iface = (get_iface_for_address(vip) or
+                     config('vip_iface'))
+            netmask = (get_netmask_for_address(vip) or
+                       config('vip_cidr'))
 
-        if iface is not None:
-            vip_key = 'res_ks_{}_vip'.format(iface)
-            if vip_key in vip_group:
-                log("Resource '%s' (vip='%s') already exists in "
-                    "vip group - skipping" % (vip_key, vip),
-                    WARNING)
-                continue
+            if iface is not None:
+                vip_key = 'res_ks_{}_vip'.format(iface)
+                if vip_key in vip_group:
+                    log("Resource '%s' (vip='%s') already exists in "
+                        "vip group - skipping" % (vip_key, vip),
+                        WARNING)
+                    continue
 
-            vip_group.append(vip_key)
-            resources[vip_key] = res_ks_vip
-            resource_params[vip_key] = (
-                'params {ip}="{vip}" cidr_netmask="{netmask}"'
-                ' nic="{iface}"'.format(ip=vip_params,
-                                        vip=vip,
-                                        iface=iface,
-                                        netmask=netmask)
-            )
+                vip_group.append(vip_key)
+                resources[vip_key] = res_ks_vip
+                resource_params[vip_key] = (
+                    'params {ip}="{vip}" cidr_netmask="{netmask}"'
+                    ' nic="{iface}"'.format(ip=vip_params,
+                                            vip=vip,
+                                            iface=iface,
+                                            netmask=netmask)
+                )
 
-    if len(vip_group) >= 1:
-        relation_set(relation_id=relation_id,
-                     groups={CLUSTER_RES: ' '.join(vip_group)})
+        if len(vip_group) >= 1:
+            relation_set(relation_id=relation_id,
+                         groups={CLUSTER_RES: ' '.join(vip_group)})
 
     init_services = {
         'res_ks_haproxy': 'haproxy'

unit_tests/test_keystone_hooks.py

@@ -56,6 +56,8 @@ TO_PATCH = [
     'configure_installation_source',
     # charmhelpers.contrib.openstack.ip
     'resolve_address',
+    # charmhelpers.contrib.openstack.ha.utils
+    'update_dns_ha_resource_params',
     # charmhelpers.contrib.hahelpers.cluster_utils
     'is_elected_leader',
     'get_hacluster_config',
@@ -832,6 +834,41 @@ class KeystoneRelationTests(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_keystone_public_hostname': 'ocf:maas:dns'})
+            resource_params.update({'res_keystone_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_ks_haproxy': 'haproxy'},
+            'resources': {'res_keystone_public_hostname': 'ocf:maas:dns',
+                          'res_ks_haproxy': 'lsb:haproxy'},
+            'resource_params': {
+                'res_keystone_public_hostname': 'params fqdn="keystone.maas" '
+                                                'ip_address="10.0.0.1"',
+                'res_ks_haproxy': 'op monitor interval="5s"'},
+            'clones': {'cl_ks_haproxy': 'res_ks_haproxy'}
+        }
+        self.update_dns_ha_resource_params.side_effect = _fake_update
+
+        hooks.ha_joined()
+        self.assertTrue(self.update_dns_ha_resource_params.called)
+        self.relation_set.assert_called_with(**args)
+
     @patch('keystone_utils.log')
     @patch('keystone_utils.ensure_ssl_cert_master')
     @patch('keystone_utils.synchronize_ca')