Add neutron-status upgrade check command framework

This adds basic framework for neutron-status upgrade check commands.

For now it has only "check_nothing" check implemented.
Real checks can be added to this tool in the future.

Depends-On: https://review.openstack.org/#/c/610061/

Change-Id: Ib08119e1bb8de80856edb6a39769d4bc9d98c587
Story: 2003657
Task: 26144

doc/source/cli/index.rst

@@ -10,3 +10,4 @@ Command-Line Interface Reference
 
    neutron-debug
    neutron-sanity-check
+   neutron-status

doc/source/cli/neutron-status.rst

@@ -0,0 +1,61 @@
+.. This file is manually generated, unlike many of the other chapters.
+
+==================================
+neutron-status command-line client
+==================================
+
+The :command:`neutron-status` provides routines for checking the status of
+Neutron deployment.
+
+.. _neutron-status_usage:
+
+neutron-status usage
+~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: console
+
+   usage: neutron-status [-h] [--config-dir DIR] [--config-file PATH]
+                         <category> <command>
+
+Categories are:
+
+* ``upgrade``
+
+Detailed descriptions are below.
+
+You can also run with a category argument such as ``upgrade`` to see a list of
+all commands in that category::
+
+    neutron-status upgrade
+
+These sections describe the available categories and arguments for
+:command:`neutron-status`.
+
+Command details
+---------------
+
+``neutron-status upgrade check``
+  Performs a release-specific readiness check before restarting services
+  with new code. This command expects to have complete configuration and access
+  to databases and services.
+
+  **Return Codes**
+
+  .. list-table::
+     :widths: 20 80
+     :header-rows: 1
+
+     * - Return code
+       - Description
+     * - 0
+       - All upgrade readiness checks passed successfully and there is nothing
+         to do.
+     * - 1
+       - At least one check encountered an issue and requires further
+         investigation. This is considered a warning but the upgrade may be OK.
+     * - 2
+       - There was an upgrade status check failure that needs to be
+         investigated. This should be considered something that stops an
+         upgrade.
+     * - 255
+       - An unexpected error occurred.

lower-constraints.txt

@@ -78,6 +78,7 @@ oslo.reports==1.18.0
 oslo.rootwrap==5.8.0
 oslo.serialization==2.18.0
 oslo.service==1.24.0
+oslo.upgradecheck==0.1.0
 oslo.utils==3.33.0
 oslo.versionedobjects==1.31.2
 oslosphinx==4.7.0

neutron/cmd/status.py

@@ -0,0 +1,53 @@
+# Copyright 2018 Red Hat Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from oslo_config import cfg
+from oslo_upgradecheck import upgradecheck
+
+from neutron._i18n import _
+
+
+class Checks(upgradecheck.UpgradeCommands):
+
+    """Various upgrade checks should be added as separate methods in this class
+    and added to _upgrade_checks tuple.
+
+    Check methods here must not rely on the neutron object model since they
+    should be able to run against both N and N-1 releases. Any queries to
+    the database should be done through the sqlalchemy query language directly
+    like the database schema migrations.
+    """
+
+    def _check_nothing(self):
+        # NOTE(slaweq) This is only example Noop check, it can be removed when
+        # some real check methods will be added
+        return upgradecheck.Result(upgradecheck.Code.SUCCESS)
+
+    # The format of the check functions is to return an
+    # oslo_upgradecheck.upgradecheck.Result
+    # object with the appropriate
+    # oslo_upgradecheck.upgradecheck.Code and details set.
+    # If the check hits warnings or failures then those should be stored
+    # in the returned Result's "details" attribute. The
+    # summary will be rolled up at the end of the check() method.
+    _upgrade_checks = (
+        # Check nothing
+        # In the future there should be some real checks added here
+        (_('Check nothing'), _check_nothing),
+    )
+
+
+def main():
+    return upgradecheck.main(
+        cfg.CONF, project='neutron', upgrade_command=Checks())

neutron/tests/unit/cmd/test_status.py

@@ -0,0 +1,29 @@
+# Copyright 2018 Red Hat Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from oslo_upgradecheck.upgradecheck import Code
+
+from neutron.cmd import status
+from neutron.tests import base
+
+
+class TestUpgradeChecks(base.BaseTestCase):
+
+    def setUp(self):
+        super(TestUpgradeChecks, self).setUp()
+        self.cmd = status.Checks()
+
+    def test__check_nothing(self):
+        check_result = self.cmd._check_nothing()
+        self.assertEqual(Code.SUCCESS, check_result.code)

releasenotes/notes/Neutron-status-upgrade-check-framework-fc34d03c8829672c.yaml

@@ -0,0 +1,13 @@
+---
+prelude: >
+    Add new tool ``neutron-status upgrade check``.
+features:
+  - |
+    New framework for ``neutron-status upgrade check`` command is added.
+    This framework allows adding various checks which can be run before a
+    Neutron upgrade to ensure if the upgrade can be performed safely.
+upgrade:
+  - |
+    Operator can now use new CLI tool ``neutron-status upgrade check``
+    to check if Neutron deployment can be safely upgraded from
+    N-1 to N release.

requirements.txt

@@ -40,6 +40,7 @@ oslo.reports>=1.18.0 # Apache-2.0
 oslo.rootwrap>=5.8.0 # Apache-2.0
 oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
 oslo.service!=1.28.1,>=1.24.0 # Apache-2.0
+oslo.upgradecheck>=0.1.0 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
 oslo.versionedobjects>=1.31.2 # Apache-2.0
 osprofiler>=1.4.0 # Apache-2.0

setup.cfg

@@ -56,6 +56,7 @@ console_scripts =
     neutron-metering-agent = neutron.cmd.eventlet.services.metering_agent:main
     neutron-sriov-nic-agent = neutron.cmd.eventlet.plugins.sriov_nic_neutron_agent:main
     neutron-sanity-check = neutron.cmd.sanity_check:main
+    neutron-status = neutron.cmd.status:main
 neutron.core_plugins =
     ml2 = neutron.plugins.ml2.plugin:Ml2Plugin
 neutron.service_plugins =