Add rpc client side version control.

This is a first pass at client side version control for rpc.  It allows
you to configure a max version of messages that clients are allowed to
send.  You can find one example of how clients need to adapt in the
conductor rpcapi.  All other changes in rpc apis since the grizzly
release are not applicable to this.

Some future improvements to this could be reporting the versions
supported by running services and having that be discoverable via the
API.  We could also consider allow setting these client side version
caps via the API.  For now, recommended values for these config
options while attempting a rolling upgrade will just have to be documented.

The config options allow specifying specific rpc api version numbers if
desired, but an alias of 'grizzly' is also supported.  So typically at
the start of a rolling upgrade you'd have:

    [upgrade_levels]
    compute=grizzly
    conductor=grizzly
    scheduler=grizzly
    ... etc ...

And as you update all instances of a service, you would remove that bit
from your configuration across the deployment using your config management
system of choice.

DocImpact

Implements blueprint rpc-version-control.

Change-Id: I2c0fd6dd7484c87823846d7c31d6525d93cd1b43

10 files changed, 184 insertions, 14 deletions

diff --git a/nova/baserpc.py b/nova/baserpc.py
index 1cb474209..b166cb400 100644
--- a/nova/baserpc.py
+++ b/nova/baserpc.py
@@ -18,11 +18,20 @@
 Base RPC client and server common to all services.
 """
 
+from oslo.config import cfg
+
 from nova.openstack.common import jsonutils
 from nova.openstack.common import rpc
 import nova.openstack.common.rpc.proxy as rpc_proxy
 
 
+CONF = cfg.CONF
+rpcapi_cap_opt = cfg.StrOpt('baseapi',
+        default=None,
+        help='Set a version cap for messages sent to the base api in any '
+             'service')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 _NAMESPACE = 'baseapi'
 
 
@@ -45,9 +54,16 @@ class BaseAPI(rpc_proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        # baseapi was added in havana
+    }
+
     def __init__(self, topic):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.baseapi,
+                                               CONF.upgrade_levels.baseapi)
         super(BaseAPI, self).__init__(topic=topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
         self.namespace = _NAMESPACE
 
     def ping(self, context, arg, timeout=None):
diff --git a/nova/cells/rpc_driver.py b/nova/cells/rpc_driver.py
index 0dcf1184c..6b11e0f05 100644
--- a/nova/cells/rpc_driver.py
+++ b/nova/cells/rpc_driver.py
@@ -34,6 +34,11 @@ CONF = cfg.CONF
 CONF.register_opts(cell_rpc_driver_opts, group='cells')
 CONF.import_opt('call_timeout', 'nova.cells.opts', group='cells')
 
+rpcapi_cap_opt = cfg.StrOpt('intercell',
+        default=None,
+        help='Set a version cap for messages sent between cells services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 _CELL_TO_CELL_RPC_API_VERSION = '1.0'
 
 
@@ -103,9 +108,21 @@ class InterCellRPCAPI(rpc_proxy.RpcProxy):
 
     API version history:
         1.0 - Initial version.
+
+        ... Grizzly supports message version 1.0.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.0.
     """
+
+    VERSION_ALIASES = {
+        'grizzly': '1.0',
+    }
+
     def __init__(self, default_version):
-        super(InterCellRPCAPI, self).__init__(None, default_version)
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.intercell,
+                                               CONF.upgrade_levels.intercell)
+        super(InterCellRPCAPI, self).__init__(None, default_version,
+                version_cap=version_cap)
 
     @staticmethod
     def _get_server_params_for_cell(next_hop):
diff --git a/nova/cells/rpcapi.py b/nova/cells/rpcapi.py
index 767498291..e65d8f490 100644
--- a/nova/cells/rpcapi.py
+++ b/nova/cells/rpcapi.py
@@ -33,6 +33,11 @@ CONF = cfg.CONF
 CONF.import_opt('enable', 'nova.cells.opts', group='cells')
 CONF.import_opt('topic', 'nova.cells.opts', group='cells')
 
+rpcapi_cap_opt = cfg.StrOpt('cells',
+        default=None,
+        help='Set a version cap for messages sent to local cells services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class CellsAPI(rpc_proxy.RpcProxy):
     '''Cells client-side RPC API
@@ -49,15 +54,27 @@ class CellsAPI(rpc_proxy.RpcProxy):
         1.5 - Adds actions_get(), action_get_by_request_id(), and
               action_events_get()
         1.6 - Adds consoleauth_delete_tokens() and validate_console_port()
+
+        ... Grizzly supports message version 1.6.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.6.
+
         1.7 - Adds service_update()
         1.8 - Adds build_instances(), deprecates schedule_run_instance()
         1.9 - Adds get_capacities()
     '''
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '1.6'
+    }
+
     def __init__(self):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.cells,
+                                               CONF.upgrade_levels.cells)
         super(CellsAPI, self).__init__(topic=CONF.cells.topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
 
     def cast_compute_api_method(self, ctxt, cell_name, method,
             *args, **kwargs):
diff --git a/nova/cert/rpcapi.py b/nova/cert/rpcapi.py
index 505efe75f..f4311b517 100644
--- a/nova/cert/rpcapi.py
+++ b/nova/cert/rpcapi.py
@@ -31,6 +31,11 @@ rpcapi_opts = [
 CONF = cfg.CONF
 CONF.register_opts(rpcapi_opts)
 
+rpcapi_cap_opt = cfg.StrOpt('cert',
+        default=None,
+        help='Set a version cap for messages sent to cert services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class CertAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     '''Client side of the cert rpc API.
@@ -39,6 +44,10 @@ class CertAPI(nova.openstack.common.rpc.proxy.RpcProxy):
 
         1.0 - Initial version.
         1.1 - Added get_backdoor_port()
+
+        ... Grizzly supports message version 1.1.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.1.
     '''
 
     #
@@ -51,10 +60,17 @@ class CertAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '1.1',
+    }
+
     def __init__(self):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.cert,
+                                               CONF.upgrade_levels.cert)
         super(CertAPI, self).__init__(
                 topic=CONF.cert_topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
 
     def revoke_certs_by_user(self, ctxt, user_id):
         return self.call(ctxt, self.make_msg('revoke_certs_by_user',
diff --git a/nova/compute/rpcapi.py b/nova/compute/rpcapi.py
index 98e90cf24..30db6010f 100644
--- a/nova/compute/rpcapi.py
+++ b/nova/compute/rpcapi.py
@@ -36,6 +36,11 @@ rpcapi_opts = [
 CONF = cfg.CONF
 CONF.register_opts(rpcapi_opts)
 
+rpcapi_cap_opt = cfg.StrOpt('compute',
+        default=None,
+        help='Set a version cap for messages sent to compute services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 def _compute_topic(topic, ctxt, host, instance):
     '''Get the topic to use for a message.
@@ -167,6 +172,11 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
                vnc on the correct port
         2.27 - Adds 'reservations' to terminate_instance() and
                soft_delete_instance()
+
+        ... Grizzly supports message version 2.27.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 2.27.
+
         2.28 - Adds check_instance_shared_storage()
         2.29 - Made start_instance() and stop_instance() take new-world
                instance objects
@@ -182,11 +192,18 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '2.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '2.27',
+    }
+
     def __init__(self):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.compute,
+                                               CONF.upgrade_levels.compute)
         super(ComputeAPI, self).__init__(
                 topic=CONF.compute_topic,
                 default_version=self.BASE_RPC_API_VERSION,
-                serializer=objects_base.NovaObjectSerializer())
+                serializer=objects_base.NovaObjectSerializer(),
+                version_cap=version_cap)
 
     def add_aggregate_host(self, ctxt, aggregate, host_param, host,
                            slave_info=None):
diff --git a/nova/conductor/rpcapi.py b/nova/conductor/rpcapi.py
index c9b1c0af7..bb66ca8b2 100644
--- a/nova/conductor/rpcapi.py
+++ b/nova/conductor/rpcapi.py
@@ -22,6 +22,11 @@ import nova.openstack.common.rpc.proxy
 
 CONF = cfg.CONF
 
+rpcapi_cap_opt = cfg.StrOpt('conductor',
+        default=None,
+        help='Set a version cap for messages sent to conductor services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class ConductorAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     """Client side of the conductor RPC API
@@ -88,6 +93,11 @@ class ConductorAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     1.47 - Added columns_to_join to instance_get_all_by_host and
                  instance_get_all_by_filters
     1.48 - Added compute_unrescue
+
+        ... Grizzly supports message version 1.48.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.48.
+
     1.49 - Added columns_to_join to instance_get_by_uuid
     1.50 - Added object_action() and object_class_action()
     1.51 - Added the 'legacy' argument to
@@ -96,11 +106,18 @@ class ConductorAPI(nova.openstack.common.rpc.proxy.RpcProxy):
 
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '1.48',
+    }
+
     def __init__(self):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.conductor,
+                                               CONF.upgrade_levels.conductor)
         super(ConductorAPI, self).__init__(
             topic=CONF.conductor.topic,
             default_version=self.BASE_RPC_API_VERSION,
-            serializer=objects_base.NovaObjectSerializer())
+            serializer=objects_base.NovaObjectSerializer(),
+            version_cap=version_cap)
 
     def instance_update(self, context, instance_uuid, updates,
                         service=None):
@@ -119,10 +136,16 @@ class ConductorAPI(nova.openstack.common.rpc.proxy.RpcProxy):
 
     def instance_get_by_uuid(self, context, instance_uuid,
                              columns_to_join=None):
-        msg = self.make_msg('instance_get_by_uuid',
-                            instance_uuid=instance_uuid,
-                            columns_to_join=columns_to_join)
-        return self.call(context, msg, version='1.49')
+        if self.can_send_version('1.49'):
+            version = '1.49'
+            msg = self.make_msg('instance_get_by_uuid',
+                                instance_uuid=instance_uuid,
+                                columns_to_join=columns_to_join)
+        else:
+            version = '1.2'
+            msg = self.make_msg('instance_get_by_uuid',
+                                instance_uuid=instance_uuid)
+        return self.call(context, msg, version=version)
 
     def migration_get(self, context, migration_id):
         msg = self.make_msg('migration_get', migration_id=migration_id)
diff --git a/nova/console/rpcapi.py b/nova/console/rpcapi.py
index 86debae32..7a78b52c2 100644
--- a/nova/console/rpcapi.py
+++ b/nova/console/rpcapi.py
@@ -31,6 +31,11 @@ rpcapi_opts = [
 CONF = cfg.CONF
 CONF.register_opts(rpcapi_opts)
 
+rpcapi_cap_opt = cfg.StrOpt('console',
+        default=None,
+        help='Set a version cap for messages sent to console services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class ConsoleAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     '''Client side of the console rpc API.
@@ -39,6 +44,10 @@ class ConsoleAPI(nova.openstack.common.rpc.proxy.RpcProxy):
 
         1.0 - Initial version.
         1.1 - Added get_backdoor_port()
+
+        ... Grizzly supports message version 1.1.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.1.
     '''
 
     #
@@ -51,11 +60,18 @@ class ConsoleAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '1.1',
+    }
+
     def __init__(self, topic=None):
         topic = topic if topic else CONF.console_topic
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.console,
+                                               CONF.upgrade_levels.console)
         super(ConsoleAPI, self).__init__(
                 topic=topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
 
     def add_console(self, ctxt, instance_id):
         self.cast(ctxt, self.make_msg('add_console', instance_id=instance_id))
diff --git a/nova/consoleauth/rpcapi.py b/nova/consoleauth/rpcapi.py
index 62aeab8da..ffc1a3de4 100644
--- a/nova/consoleauth/rpcapi.py
+++ b/nova/consoleauth/rpcapi.py
@@ -24,6 +24,11 @@ import nova.openstack.common.rpc.proxy
 
 CONF = cfg.CONF
 
+rpcapi_cap_opt = cfg.StrOpt('consoleauth',
+        default=None,
+        help='Set a version cap for messages sent to consoleauth services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class ConsoleAuthAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     '''Client side of the consoleauth rpc API.
@@ -34,6 +39,10 @@ class ConsoleAuthAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         1.1 - Added get_backdoor_port()
         1.2 - Added instance_uuid to authorize_console, and
               delete_tokens_for_instance
+
+        ... Grizzly supports message version 1.2.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.2.
     '''
 
     #
@@ -46,10 +55,17 @@ class ConsoleAuthAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '1.2',
+    }
+
     def __init__(self):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.consoleauth,
+                                               CONF.upgrade_levels.consoleauth)
         super(ConsoleAuthAPI, self).__init__(
                 topic=CONF.consoleauth_topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
 
     def authorize_console(self, ctxt, token, console_type, host, port,
                           internal_access_path, instance_uuid=None):
diff --git a/nova/network/rpcapi.py b/nova/network/rpcapi.py
index c335c9cb4..1fa5610ca 100644
--- a/nova/network/rpcapi.py
+++ b/nova/network/rpcapi.py
@@ -37,6 +37,11 @@ rpcapi_opts = [
 CONF = cfg.CONF
 CONF.register_opts(rpcapi_opts)
 
+rpcapi_cap_opt = cfg.StrOpt('network',
+        default=None,
+        help='Set a version cap for messages sent to network services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class NetworkAPI(rpc_proxy.RpcProxy):
     '''Client side of the network rpc API.
@@ -54,6 +59,10 @@ class NetworkAPI(rpc_proxy.RpcProxy):
         1.8 - Adds macs to allocate_for_instance
         1.9 - Adds rxtx_factor to [add|remove]_fixed_ip, removes instance_uuid
               from allocate_for_instance and instance_get_nw_info
+
+        ... Grizzly supports message version 1.9.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 1.9.
     '''
 
     #
@@ -66,11 +75,18 @@ class NetworkAPI(rpc_proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '1.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '1.9',
+    }
+
     def __init__(self, topic=None):
         topic = topic if topic else CONF.network_topic
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.network,
+                                               CONF.upgrade_levels.network)
         super(NetworkAPI, self).__init__(
                 topic=topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
 
     def get_all_networks(self, ctxt):
         return self.call(ctxt, self.make_msg('get_all_networks'))
diff --git a/nova/scheduler/rpcapi.py b/nova/scheduler/rpcapi.py
index 2cfd5688f..369363bb4 100644
--- a/nova/scheduler/rpcapi.py
+++ b/nova/scheduler/rpcapi.py
@@ -32,6 +32,11 @@ rpcapi_opts = [
 CONF = cfg.CONF
 CONF.register_opts(rpcapi_opts)
 
+rpcapi_cap_opt = cfg.StrOpt('scheduler',
+        default=None,
+        help='Set a version cap for messages sent to scheduler services')
+CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')
+
 
 class SchedulerAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     '''Client side of the scheduler rpc API.
@@ -58,6 +63,10 @@ class SchedulerAPI(nova.openstack.common.rpc.proxy.RpcProxy):
                 - accepts a list of capabilities
         2.5 - Add get_backdoor_port()
         2.6 - Add select_hosts()
+
+        ... Grizzly supports message version 2.6.  So, any changes to existing
+        methods in 2.x after that point should be done such that they can
+        handle the version_cap being set to 2.6.
     '''
 
     #
@@ -70,9 +79,16 @@ class SchedulerAPI(nova.openstack.common.rpc.proxy.RpcProxy):
     #
     BASE_RPC_API_VERSION = '2.0'
 
+    VERSION_ALIASES = {
+        'grizzly': '2.6',
+    }
+
     def __init__(self):
+        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.scheduler,
+                                               CONF.upgrade_levels.scheduler)
         super(SchedulerAPI, self).__init__(topic=CONF.scheduler_topic,
-                default_version=self.BASE_RPC_API_VERSION)
+                default_version=self.BASE_RPC_API_VERSION,
+                version_cap=version_cap)
 
     def run_instance(self, ctxt, request_spec, admin_password,
             injected_files, requested_networks, is_first_time,