Remove dependency on openvswitch-switch daemons

While the ovn packages have a dependency on the
`openvswitch-switch` and `openvswitch-common` packages the OVN
central components have no need for having the daemons running.

Also fixes an issue with the ovn-central systemd service file
which lead to unwanted reverse dependency between `ovn-northd` and
the database services.  I.e. we do not want a restart of
`ovn-northd` to lead to a reastart of the `ovn-nb-ovsdb` service.

Remove loading of `openvswitch` kernel module from LXD profile,
add in iptables instead as we will need this to protect the SB
DB listener created for accepting connections from `ovn-northd`

Change-Id: I134ec560c5522f0c657c203a4cd828e0e5c6f3cb

src/lib/charm/openstack/ovn_central.py

@@ -94,12 +94,19 @@ class OVNCentralCharm(charms_openstack.charm.OpenStackCharm):
         We also configure source before installing as OpenvSwitch and OVN
         packages are distributed as part of the UCA.
         """
+        # NOTE(fnordahl) The OVN central components are currently packaged with
+        # a dependency on openvswitch-switch, but it does not need the switch
+        # or stock ovsdb running.
         service_masks = [
-            '/etc/systemd/system/ovn-central.service',
+            'openvswitch-switch.service',
+            'ovs-vswitchd.service',
+            'ovsdb-server.service',
+            'ovn-central.service',
         ]
         for service_file in service_masks:
-            if not os.path.islink(service_file):
+            abs_path_svc = os.path.join('/etc/systemd/system', service_file)
-                os.symlink('/dev/null', service_file)
+            if not os.path.islink(abs_path_svc):
+                os.symlink('/dev/null', abs_path_svc)
         self.configure_source()
         super().install()
 
@@ -196,11 +203,6 @@ class OVNCentralCharm(charms_openstack.charm.OpenStackCharm):
                                 tls_object['cert'],
                                 tls_object['key'],
                                 cn='host')
-            self.run('ovs-vsctl',
-                     'set-ssl',
-                     ovn_key(self.adapters_instance),
-                     ovn_cert(self.adapters_instance),
-                     ovn_ca_cert(self.adapters_instance))
             if (reactive.is_flag_set('leadership.is_leader') and not
                     reactive.is_flag_set('leadership.set.ready')):
                 # This is one-time set up at cluster creation and can only be
@@ -238,19 +240,3 @@ class OVNCentralCharm(charms_openstack.charm.OpenStackCharm):
                          'add', 'SB_Global', '.', 'connections', '@connection')
             self.restart_all()
             break
-
-    def configure_ovn_remote(self, ovsdb_interface):
-        """Configure the OVN remote setting in the local OVSDB.
-
-        The value is used by command line tools run on this unit.
-
-        :param ovsdb_interface: OVSDB interface instance
-        :type ovsdb_interface: reactive.Endpoint derived class
-        :raises: subprocess.CalledProcessError
-        """
-        self.run('ovs-vsctl',
-                 'set',
-                 'open',
-                 '.',
-                 'external-ids:ovn-remote={}'
-                 .format(','.join(ovsdb_interface.db_sb_connection_strs)))

src/lxd-profile.yaml

@@ -1,6 +1,2 @@
-comment: |
-  NOTE(fnordahl): This is not required by the services the charm ultimately
-  will run, but is currently required by how it is packaged.  We should work
-  towards not having this dependency.
 config:
-  linux.kernel_modules: openvswitch
+  linux.kernel_modules: ip_tables,ip6_tables

src/reactive/ovn_central_handlers.py

@@ -146,6 +146,5 @@ def render():
                                    ovsdb_peer.cluster_remote_addrs,
                                    ovsdb_peer.db_sb_cluster_port))
         if ovn_charm.enable_services():
-            ovn_charm.configure_ovn_remote(ovsdb_peer)
             reactive.set_flag('config.rendered')
         ovn_charm.assess_status()

src/templates/ovn-central.service

@@ -6,10 +6,8 @@
 [Unit]
 Description=Open Virtual Network central components
 After=network.target
-After=openvswitch-switch.service
 Requires=network.target
-Requires=openvswitch-switch.service
+Wants=ovn-northd.service
-Requires=ovn-northd.service
 # Facilitate spread placement of the DBs if someone should choose to do that
 Wants=ovn-nb-ovsdb.service
 Wants=ovn-sb-ovsdb.service

src/templates/ovn-nb-ovsdb.service

@@ -5,7 +5,7 @@
 ###############################################################################
 [Unit]
 Description=Open vSwitch database server for OVN Northbound database
-After=network.target openvswitch-switch.service
+After=network.target
 PartOf=ovn-central.service
 DefaultDependencies=no
 

src/templates/ovn-sb-ovsdb.service

@@ -5,7 +5,7 @@
 ###############################################################################
 [Unit]
 Description=Open vSwitch database server for OVN Southbound database
-After=network.target openvswitch-switch.service
+After=network.target
 PartOf=ovn-central.service
 DefaultDependencies=no
 

unit_tests/test_lib_charm_openstack_ovn_central.py

@@ -65,12 +65,14 @@ class TestOVNCentralCharm(Helper):
         self.patch_target('configure_source')
         self.target.install()
         calls = []
-        for service in self.target.services:
+        for service in ('openvswitch-switch', 'ovs-vswitchd', 'ovsdb-server',
+                        self.target.services[0],):
             calls.append(
                 mock.call('/etc/systemd/system/{}.service'.format(service)))
         self.islink.assert_has_calls(calls)
         calls = []
-        for service in self.target.services:
+        for service in ('openvswitch-switch', 'ovs-vswitchd', 'ovsdb-server',
+                        self.target.services[0],):
             calls.append(
                 mock.call('/dev/null',
                           '/etc/systemd/system/{}.service'.format(service)))
@@ -161,11 +163,6 @@ class TestOVNCentralCharm(Helper):
                 'fakekey',
                 cn='host')
             self.target.run.assert_has_calls([
-                mock.call('ovs-vsctl',
-                          'set-ssl',
-                          '/etc/openvswitch/key_host',
-                          '/etc/openvswitch/cert_host',
-                          '/etc/openvswitch/ovn-central.crt'),
                 mock.call('ovn-nbctl',
                           'set-connection',
                           'pssl:6641'),
@@ -178,28 +175,3 @@ class TestOVNCentralCharm(Helper):
                           'add', 'SB_Global', '.', 'connections',
                           '@connection'),
             ])
-            self.is_flag_set.side_effect = [False, True]
-            self.target.run.reset_mock()
-            self.target.configure_tls()
-            self.target.run.assert_has_calls([
-                mock.call('ovs-vsctl',
-                          'set-ssl',
-                          '/etc/openvswitch/key_host',
-                          '/etc/openvswitch/cert_host',
-                          '/etc/openvswitch/ovn-central.crt'),
-            ])
-
-    def test_configure_ovn_remote(self):
-        self.patch_target('run')
-        ovsdb_interface = mock.MagicMock()
-        ovsdb_interface.db_sb_connection_strs = \
-            mock.PropertyMock().return_value = [
-                'ssl:a.b.c.d:6642',
-                'ssl:a.b.c.d:6642',
-                'ssl:a.b.c.d:6642',
-            ]
-        self.target.configure_ovn_remote(ovsdb_interface)
-        self.run.assert_called_once_with(
-            'ovs-vsctl', 'set', 'open', '.',
-            'external-ids:ovn-remote='
-            'ssl:a.b.c.d:6642,ssl:a.b.c.d:6642,ssl:a.b.c.d:6642')