Add "none" RPC transport that disables the RPC bus

When using the new combined executable in a single-conductor scenario,
it may make sense to completely disable the remote RPC. The new
``rpc_transport`` value ``none`` achieves that.

Change-Id: I6a83358c65b3ed213c8a991d42660ca51fc3a8ec
Story: #2009676
Task: #44104

11 files changed, 123 insertions, 16 deletions

diff --git a/doc/source/install/standalone/configure.rst b/doc/source/install/standalone/configure.rst
index 906e58b2c..fc540d986 100644
--- a/doc/source/install/standalone/configure.rst
+++ b/doc/source/install/standalone/configure.rst
@@ -92,6 +92,20 @@ You should make the following changes to ``/etc/ironic/ironic.conf``:
     username = myName
     password = myPassword
 
+#. Starting with the Yoga release series, you can use a combined API+conductor
+   service and completely disable the RPC. Set
+
+   .. code-block:: ini
+
+    [DEFAULT]
+    rpc_transport = none
+
+   and use the ``ironic`` executable to start the combined service.
+
+   .. note::
+      The combined service also works with RPC enabled, which can be useful for
+      some deployments, but may not be advisable for all security models.
+
 Using CLI
 ---------
 
diff --git a/ironic/api/wsgi.py b/ironic/api/wsgi.py
index 467389701..bf98de90f 100644
--- a/ironic/api/wsgi.py
+++ b/ironic/api/wsgi.py
@@ -30,6 +30,7 @@ def initialize_wsgi_app(argv=sys.argv):
     i18n.install('ironic')
 
     service.prepare_command(argv)
+    service.ensure_rpc_transport()
 
     LOG.debug("Configuration:")
     CONF.log_opt_values(LOG, log.DEBUG)
diff --git a/ironic/cmd/api.py b/ironic/cmd/api.py
index 4a4b381c8..2323c4b09 100644
--- a/ironic/cmd/api.py
+++ b/ironic/cmd/api.py
@@ -33,6 +33,7 @@ LOG = log.getLogger(__name__)
 def main():
     # Parse config file and command line options, then start logging
     ironic_service.prepare_service('ironic_api', sys.argv)
+    ironic_service.ensure_rpc_transport()
 
     # Build and start the WSGI app
     launcher = ironic_service.process_launcher()
diff --git a/ironic/cmd/conductor.py b/ironic/cmd/conductor.py
index 19fb05cb4..843185890 100644
--- a/ironic/cmd/conductor.py
+++ b/ironic/cmd/conductor.py
@@ -58,6 +58,7 @@ def main():
 
     # Parse config file and command line options, then start logging
     ironic_service.prepare_service('ironic_conductor', sys.argv)
+    ironic_service.ensure_rpc_transport(CONF)
 
     mgr = rpc_service.RPCService(CONF.host,
                                  'ironic.conductor.manager',
diff --git a/ironic/common/rpc_service.py b/ironic/common/rpc_service.py
index bbf38d7f4..78379c981 100644
--- a/ironic/common/rpc_service.py
+++ b/ironic/common/rpc_service.py
@@ -53,19 +53,22 @@ class RPCService(service.Service):
         if CONF.rpc_transport == 'json-rpc':
             self.rpcserver = json_rpc.WSGIService(
                 self.manager, serializer, context.RequestContext.from_dict)
-        else:
+        elif CONF.rpc_transport != 'none':
             target = messaging.Target(topic=self.topic, server=self.host)
             endpoints = [self.manager]
             self.rpcserver = rpc.get_server(target, endpoints, serializer)
-        self.rpcserver.start()
+
+        if self.rpcserver is not None:
+            self.rpcserver.start()
 
         self.handle_signal()
         self.manager.init_host(admin_context)
         rpc.set_global_manager(self.manager)
 
-        LOG.info('Created RPC server for service %(service)s on host '
-                 '%(host)s.',
-                 {'service': self.topic, 'host': self.host})
+        LOG.info('Created RPC server with %(transport)s transport for service '
+                 '%(service)s on host %(host)s.',
+                 {'service': self.topic, 'host': self.host,
+                  'transport': CONF.rpc_transport})
 
     def stop(self):
         try:
diff --git a/ironic/common/service.py b/ironic/common/service.py
index db83c147a..c30df6f56 100644
--- a/ironic/common/service.py
+++ b/ironic/common/service.py
@@ -69,3 +69,11 @@ def prepare_service(name, argv=None, conf=CONF):
 
 def process_launcher():
     return service.ProcessLauncher(CONF, restart_method='mutate')
+
+
+def ensure_rpc_transport(conf=CONF):
+    # Only the combined ironic executable can use rpc_transport = none
+    if conf.rpc_transport == 'none':
+        raise RuntimeError("This service is not designed to work with "
+                           "rpc_transport = none. Please use the combined "
+                           "ironic executable or another RPC transport.")
diff --git a/ironic/conductor/rpcapi.py b/ironic/conductor/rpcapi.py
index 6f4971be7..21139e60d 100644
--- a/ironic/conductor/rpcapi.py
+++ b/ironic/conductor/rpcapi.py
@@ -174,10 +174,12 @@ class ConductorAPI(object):
             self.client = json_rpc.Client(serializer=serializer,
                                           version_cap=version_cap)
             self.topic = ''
-        else:
+        elif CONF.rpc_transport != 'none':
             target = messaging.Target(topic=self.topic, version='1.0')
             self.client = rpc.get_client(target, version_cap=version_cap,
                                          serializer=serializer)
+        else:
+            self.client = None
 
         # NOTE(tenbrae): this is going to be buggy
         self.ring_manager = hash_ring.HashRingManager()
@@ -203,6 +205,13 @@ class ConductorAPI(object):
             # conductor.
             return _LOCAL_CONTEXT
 
+        # A safeguard for the case someone uses rpc_transport=None with no
+        # built-in conductor.
+        if self.client is None:
+            raise exception.ServiceUnavailable(
+                _("Cannot use 'none' RPC to connect to remote conductor %s")
+                % host)
+
         # Normal RPC path
         return self.client.prepare(topic=topic, version=version)
 
@@ -276,13 +285,17 @@ class ConductorAPI(object):
         """Get RPC topic name for the current conductor."""
         return self.topic + "." + CONF.host
 
+    def _can_send_version(self, version):
+        return (self.client.can_send_version(version)
+                if self.client is not None else True)
+
     def can_send_create_port(self):
         """Return whether the RPCAPI supports the create_port method."""
-        return self.client.can_send_version("1.41")
+        return self._can_send_version("1.41")
 
     def can_send_rescue(self):
         """Return whether the RPCAPI supports node rescue methods."""
-        return self.client.can_send_version("1.43")
+        return self._can_send_version("1.43")
 
     def create_node(self, context, node_obj, topic=None):
         """Synchronously, have a conductor validate and create a node.
@@ -1047,16 +1060,16 @@ class ConductorAPI(object):
         """
         new_kws = {}
         version = '1.34'
-        if self.client.can_send_version('1.42'):
+        if self._can_send_version('1.42'):
             version = '1.42'
             new_kws['agent_version'] = agent_version
-        if self.client.can_send_version('1.49'):
+        if self._can_send_version('1.49'):
             version = '1.49'
             new_kws['agent_token'] = agent_token
-        if self.client.can_send_version('1.51'):
+        if self._can_send_version('1.51'):
             version = '1.51'
             new_kws['agent_verify_ca'] = agent_verify_ca
-        if self.client.can_send_version('1.54'):
+        if self._can_send_version('1.54'):
             version = '1.54'
             new_kws['agent_status'] = agent_status
             new_kws['agent_status_message'] = agent_status_message
@@ -1082,7 +1095,7 @@ class ConductorAPI(object):
         :returns: The result of the action method, which may (or may not)
             be an instance of the implementing VersionedObject class.
         """
-        if not self.client.can_send_version('1.31'):
+        if not self._can_send_version('1.31'):
             raise NotImplementedError(_('Incompatible conductor version - '
                                         'please upgrade ironic-conductor '
                                         'first'))
@@ -1108,7 +1121,7 @@ class ConductorAPI(object):
         :returns: A tuple with the updates made to the object and
             the result of the action method
         """
-        if not self.client.can_send_version('1.31'):
+        if not self._can_send_version('1.31'):
             raise NotImplementedError(_('Incompatible conductor version - '
                                         'please upgrade ironic-conductor '
                                         'first'))
@@ -1133,7 +1146,7 @@ class ConductorAPI(object):
             upgrade
         :returns: The downgraded instance of objinst
         """
-        if not self.client.can_send_version('1.31'):
+        if not self._can_send_version('1.31'):
             raise NotImplementedError(_('Incompatible conductor version - '
                                         'please upgrade ironic-conductor '
                                         'first'))
diff --git a/ironic/conf/default.py b/ironic/conf/default.py
index 1399b4f2e..3a6d3721d 100644
--- a/ironic/conf/default.py
+++ b/ironic/conf/default.py
@@ -362,7 +362,8 @@ service_opts = [
     cfg.StrOpt('rpc_transport',
                default='oslo',
                choices=[('oslo', _('use oslo.messaging transport')),
-                        ('json-rpc', _('use JSON RPC transport'))],
+                        ('json-rpc', _('use JSON RPC transport')),
+                        ('none', _('No RPC, only use local conductor'))],
                help=_('Which RPC transport implementation to use between '
                       'conductor and API services')),
     cfg.BoolOpt('minimum_memory_warning_only',
diff --git a/ironic/tests/unit/common/test_rpc_service.py b/ironic/tests/unit/common/test_rpc_service.py
index 4ba3b200a..4e190f5e6 100644
--- a/ironic/tests/unit/common/test_rpc_service.py
+++ b/ironic/tests/unit/common/test_rpc_service.py
@@ -55,3 +55,25 @@ class TestRPCService(base.TestCase):
         mock_init_method.assert_called_once_with(self.rpc_svc.manager,
                                                  mock_ctx.return_value)
         self.assertIs(rpc.GLOBAL_MANAGER, self.rpc_svc.manager)
+
+    @mock.patch.object(manager.ConductorManager, 'prepare_host', autospec=True)
+    @mock.patch.object(oslo_messaging, 'Target', autospec=True)
+    @mock.patch.object(objects_base, 'IronicObjectSerializer', autospec=True)
+    @mock.patch.object(rpc, 'get_server', autospec=True)
+    @mock.patch.object(manager.ConductorManager, 'init_host', autospec=True)
+    @mock.patch.object(context, 'get_admin_context', autospec=True)
+    def test_start_no_rpc(self, mock_ctx, mock_init_method,
+                          mock_rpc, mock_ios, mock_target,
+                          mock_prepare_method):
+        CONF.set_override('rpc_transport', 'none')
+        self.rpc_svc.start()
+
+        self.assertIsNone(self.rpc_svc.rpcserver)
+        mock_ctx.assert_called_once_with()
+        mock_target.assert_not_called()
+        mock_rpc.assert_not_called()
+        mock_ios.assert_called_once_with(is_server=True)
+        mock_prepare_method.assert_called_once_with(self.rpc_svc.manager)
+        mock_init_method.assert_called_once_with(self.rpc_svc.manager,
+                                                 mock_ctx.return_value)
+        self.assertIs(rpc.GLOBAL_MANAGER, self.rpc_svc.manager)
diff --git a/ironic/tests/unit/conductor/test_rpcapi.py b/ironic/tests/unit/conductor/test_rpcapi.py
index d207bb2f7..56f67b2c2 100644
--- a/ironic/tests/unit/conductor/test_rpcapi.py
+++ b/ironic/tests/unit/conductor/test_rpcapi.py
@@ -77,6 +77,12 @@ class RPCAPITestCase(db_base.DbTestCase):
             self.context, objects.Node(), self.fake_node)
         self.fake_portgroup = db_utils.get_test_portgroup()
 
+    def test_rpc_disabled(self):
+        CONF.set_override('rpc_transport', 'none')
+        rpcapi = conductor_rpcapi.ConductorAPI(topic='fake-topic')
+        self.assertIsNone(rpcapi.client)
+        self.assertTrue(rpcapi._can_send_version('9.99'))
+
     def test_serialized_instance_has_uuid(self):
         self.assertIn('uuid', self.fake_node)
 
@@ -728,6 +734,17 @@ class RPCAPITestCase(db_base.DbTestCase):
 
     @mock.patch.object(rpc, 'GLOBAL_MANAGER',
                        spec_set=conductor_manager.ConductorManager)
+    def test_local_call_with_rpc_disabled(self, mock_manager):
+        CONF.set_override('host', 'fake.host')
+        CONF.set_override('rpc_transport', 'none')
+        rpcapi = conductor_rpcapi.ConductorAPI(topic='fake.topic')
+        rpcapi.create_node(mock.sentinel.context, mock.sentinel.node,
+                           topic='fake.topic.fake.host')
+        mock_manager.create_node.assert_called_once_with(
+            mock.sentinel.context, node_obj=mock.sentinel.node)
+
+    @mock.patch.object(rpc, 'GLOBAL_MANAGER',
+                       spec_set=conductor_manager.ConductorManager)
     def test_local_call_host_mismatch(self, mock_manager):
         CONF.set_override('host', 'fake.host')
         rpcapi = conductor_rpcapi.ConductorAPI(topic='fake.topic')
@@ -740,6 +757,27 @@ class RPCAPITestCase(db_base.DbTestCase):
 
     @mock.patch.object(rpc, 'GLOBAL_MANAGER',
                        spec_set=conductor_manager.ConductorManager)
+    def test_local_call_host_mismatch_with_rpc_disabled(self, mock_manager):
+        CONF.set_override('host', 'fake.host')
+        CONF.set_override('rpc_transport', 'none')
+        rpcapi = conductor_rpcapi.ConductorAPI(topic='fake.topic')
+        self.assertRaises(exception.ServiceUnavailable,
+                          rpcapi.create_node,
+                          mock.sentinel.context, mock.sentinel.node,
+                          topic='fake.topic.not-fake.host')
+
+    @mock.patch.object(rpc, 'GLOBAL_MANAGER', None)
+    def test_local_call_no_conductor_with_rpc_disabled(self):
+        CONF.set_override('host', 'fake.host')
+        CONF.set_override('rpc_transport', 'none')
+        rpcapi = conductor_rpcapi.ConductorAPI(topic='fake.topic')
+        self.assertRaises(exception.ServiceUnavailable,
+                          rpcapi.create_node,
+                          mock.sentinel.context, mock.sentinel.node,
+                          topic='fake.topic.fake.host')
+
+    @mock.patch.object(rpc, 'GLOBAL_MANAGER',
+                       spec_set=conductor_manager.ConductorManager)
     def test_local_cast(self, mock_manager):
         CONF.set_override('host', 'fake.host')
         rpcapi = conductor_rpcapi.ConductorAPI(topic='fake.topic')
diff --git a/releasenotes/notes/rpc-none-f05dac657eef4b66.yaml b/releasenotes/notes/rpc-none-f05dac657eef4b66.yaml
new file mode 100644
index 000000000..332ed241a
--- /dev/null
+++ b/releasenotes/notes/rpc-none-f05dac657eef4b66.yaml
@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Adds a new ``none`` RPC transport that can be used together with the
+    combined ``ironic`` executable to completely disable the RPC bus.