Add framework for octavia-status upgrade check

This commit adds the functionality of octavia-status CLI for performing
upgrade checks as part of the Stein cycle upgrade-checkers goal.
It only includes a sample check which must be replaced by real checks in
future.

Change-Id: I8b6d134b0bf5b5c82a19177fed6145ef8aaf7507
Story: 2003657
Task: 26146

doc/source/admin/guides/upgrade.rst

@@ -50,6 +50,9 @@ of upgrading. In the case of the Load Balancing service, it means no downtime
 nor reconfiguration of service-managed resources (e.g. load balancers,
 listeners, pools and members).
 
+#. Run the :ref:`octavia-status upgrade check <octavia-status-checks>`
+   command to validate that Octavia is ready for upgrade.
+
 #. Gracefully stop all Octavia processes. We recommend in this order:
    Housekeeping, Health manager, API, Worker.
 

doc/source/admin/index.rst

@@ -31,6 +31,7 @@ Operator Reference
    ../contributor/guides/dev-quick-start.rst
    guides/operator-maintenance.rst
    guides/upgrade.rst
+   octavia-status
    ../configuration/configref.rst
    ../configuration/policy.rst
    Anchor.rst

doc/source/admin/octavia-status.rst

@@ -0,0 +1,83 @@
+==============
+octavia-status
+==============
+
+-----------------------------------------
+CLI interface for Octavia status commands
+-----------------------------------------
+
+Synopsis
+========
+
+::
+
+  octavia-status <category> <command> [<args>]
+
+Description
+===========
+
+:program:`octavia-status` is a tool that provides routines for checking the
+status of a Octavia deployment.
+
+Options
+=======
+
+The standard pattern for executing a :program:`octavia-status` command is::
+
+    octavia-status <category> <command> [<args>]
+
+Run without arguments to see a list of available command categories::
+
+    octavia-status
+
+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::
+
+    octavia-status upgrade
+
+These sections describe the available categories and arguments for
+:program:`octavia-status`.
+
+Upgrade
+~~~~~~~
+
+.. _octavia-status-checks:
+
+``octavia-status upgrade check``
+  Performs a release-specific readiness check before restarting services with
+  new code. For example, missing or changed configuration options,
+  incompatible object states, or other conditions that could lead to
+  failures while upgrading.
+
+  **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.
+
+  **History of Checks**
+
+  **4.0.0 (Stein)**
+
+  * Sample check to be filled in with checks as they are added in Stein.

lower-constraints.txt

@@ -89,6 +89,7 @@ oslo.policy==1.30.0
 oslo.reports==1.18.0
 oslo.serialization==2.18.0
 oslo.service==1.30.0
+oslo.upgradecheck==0.1.0
 oslo.utils==3.33.0
 oslotest==3.2.0
 packaging==17.1

octavia/cmd/status.py

@@ -0,0 +1,53 @@
+# Copyright (c) 2018 NEC, Corp.
+#
+#    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.
+
+import sys
+
+from oslo_config import cfg
+from oslo_upgradecheck import upgradecheck
+
+from octavia.i18n import _
+
+CONF = cfg.CONF
+
+
+class Checks(upgradecheck.UpgradeCommands):
+
+    """Contains upgrade checks
+
+    Various upgrade checks should be added as separate methods in this class
+    and added to _upgrade_checks tuple.
+    """
+
+    def _sample_check(self):
+        """This is sample check added to test the upgrade check framework
+
+        It needs to be removed after adding any real upgrade check
+        """
+        return upgradecheck.Result(upgradecheck.Code.SUCCESS, 'Sample detail')
+
+    _upgrade_checks = (
+        # Sample check added for now.
+        # Whereas in future real checks must be added here in tuple
+        (_('Sample Check'), _sample_check),
+    )
+
+
+def main():
+    return upgradecheck.main(
+        CONF, project='octavia', upgrade_command=Checks())
+
+
+if __name__ == '__main__':
+    sys.exit(main())

octavia/tests/unit/cmd/test_status.py

@@ -0,0 +1,30 @@
+# Copyright (c) 2018 NEC, Corp.
+#
+#    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 octavia.cmd import status
+from octavia.tests.unit import base
+
+
+class TestUpgradeChecks(base.TestCase):
+
+    def setUp(self):
+        super(TestUpgradeChecks, self).setUp()
+        self.cmd = status.Checks()
+
+    def test__sample_check(self):
+        check_result = self.cmd._sample_check()
+        self.assertEqual(
+            Code.SUCCESS, check_result.code)

releasenotes/notes/add-upgrade-check-framework-cc440f3f440ba6d2.yaml

@@ -0,0 +1,11 @@
+---
+features:
+  - |
+    Added new tool ``octavia-status upgrade check``.
+    This framework allows adding various checks which can be run before a
+    Octavia upgrade to ensure if the upgrade can be performed safely.
+upgrade:
+  - |
+    Operator can now use new CLI tool ``octavia-status upgrade check``
+    to check if Octavia deployment can be safely upgraded from
+    N-1 to N release.

requirements.txt

@@ -25,6 +25,7 @@ oslo.messaging>=5.29.0 # Apache-2.0
 oslo.middleware>=3.31.0 # Apache-2.0
 oslo.policy>=1.30.0 # Apache-2.0
 oslo.reports>=1.18.0 # Apache-2.0
+oslo.upgradecheck>=0.1.0 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
 pyasn1!=0.2.3,>=0.1.8 # BSD
 pyasn1-modules>=0.0.6 # BSD

setup.cfg

@@ -51,6 +51,7 @@ console_scripts =
     octavia-db-manage = octavia.db.migration.cli:main
     amphora-agent = octavia.cmd.agent:main
     haproxy-vrrp-check = octavia.cmd.haproxy_vrrp_check:main
+    octavia-status = octavia.cmd.status:main
 octavia.api.drivers =
     noop_driver = octavia.api.drivers.noop_driver.driver:NoopProviderDriver
     amphora = octavia.api.drivers.amphora_driver.driver:AmphoraProviderDriver