From 1fdfa3332321d9dd1246c7d13c77d93c10f7c3b3 Mon Sep 17 00:00:00 2001
From: Michele Baldessari <michele@acksyn.org>
Date: Tue, 18 Aug 2020 10:29:19 +0200
Subject: [PATCH] Fix pcs restart in composable HA

When a redeploy command is being run in a composable HA environment, if there
are any configuration changes, the <bundle>_restart containers will be kicked
off. These restart containers will then try and restart the bundles globally in
the cluster.

These restarts will be fired off in parallel from different nodes. So
haproxy-bundle will be restarted from controller-0, mysql-bundle from
database-0, rabbitmq-bundle from messaging-0.

This has proven to be problematic and very often (rhbz#1868113) it would fail
the redeploy with:
2020-08-11T13:40:25.996896822+00:00 stderr F Error: Could not complete shutdown of rabbitmq-bundle, 1 resources remaining
2020-08-11T13:40:25.996896822+00:00 stderr F Error performing operation: Timer expired
2020-08-11T13:40:25.996896822+00:00 stderr F Set 'rabbitmq-bundle' option: id=rabbitmq-bundle-meta_attributes-target-role set=rabbitmq-bundle-meta_attributes name=target-role value=stopped
2020-08-11T13:40:25.996896822+00:00 stderr F Waiting for 2 resources to stop:
2020-08-11T13:40:25.996896822+00:00 stderr F * galera-bundle
2020-08-11T13:40:25.996896822+00:00 stderr F * rabbitmq-bundle
2020-08-11T13:40:25.996896822+00:00 stderr F * galera-bundle
2020-08-11T13:40:25.996896822+00:00 stderr F Deleted 'rabbitmq-bundle' option: id=rabbitmq-bundle-meta_attributes-target-role name=target-role
2020-08-11T13:40:25.996896822+00:00 stderr F

or

2020-08-11T13:39:49.197487180+00:00 stderr F Waiting for 2 resources to start again:
2020-08-11T13:39:49.197487180+00:00 stderr F * galera-bundle
2020-08-11T13:39:49.197487180+00:00 stderr F * rabbitmq-bundle
2020-08-11T13:39:49.197487180+00:00 stderr F Could not complete restart of galera-bundle, 1 resources remaining
2020-08-11T13:39:49.197487180+00:00 stderr F * rabbitmq-bundle
2020-08-11T13:39:49.197487180+00:00 stderr F

After discussing it with kgaillot it seems that concurrent restarts in pcmk are just brittle:
"""
Sadly restarts are brittle, and they do in fact assume that nothing else is causing resources to start or stop. They work like this:

- Get the current configuration and state of the cluster, including a list of active resources (list #1)
- Set resource target-role to Stopped
- Get the current configuration and state of the cluster, including a list of which resources *should* be active (list #2)
- Compare lists #1 and #2, and the difference is the resources that should stop
- Periodically refresh the configuration and state until the list of active resources matches list #2
- Delete the target-role
- Periodically refresh the configuration and state until the list of active resources matches list #1
"""

So the suggestion is to replace the restarts with an enable/disable cycle of the resource.

Tested this on a dozen runs on a composable HA environment and did not observe the error
any longer.

Closes-Bug: #1892206

Change-Id: I9cc27b1539a62a88fb0bccac64e6b1ae9295f22e
---
 container_config_scripts/pacemaker_restart_bundle.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/container_config_scripts/pacemaker_restart_bundle.sh b/container_config_scripts/pacemaker_restart_bundle.sh
index 665fe1ebc0..9d5fc058c3 100755
--- a/container_config_scripts/pacemaker_restart_bundle.sh
+++ b/container_config_scripts/pacemaker_restart_bundle.sh
@@ -41,8 +41,10 @@ if [ x"${TRIPLEO_MINOR_UPDATE,,}" != x"true" ]; then
             if [[ "${HOSTNAME,,}" == "${SERVICE_NODEID,,}" ]]; then
                 replicas_running=$(crm_resource -Q -r $BUNDLE_NAME --locate 2>&1 | wc -l)
                 if [ "$replicas_running" != "0" ]; then
-                    echo "$(date -u): Restarting ${BUNDLE_NAME} globally"
-                    /sbin/pcs resource restart --wait=__PCMKTIMEOUT__ $BUNDLE_NAME
+                    echo "$(date -u): Restarting ${BUNDLE_NAME} globally. Stopping:"
+                    /sbin/pcs resource disable --wait=__PCMKTIMEOUT__ $BUNDLE_NAME
+                    echo "$(date -u): Restarting ${BUNDLE_NAME} globally. Starting:"
+                    /sbin/pcs resource enable --wait=__PCMKTIMEOUT__ $BUNDLE_NAME
                 else
                     echo "$(date -u): ${BUNDLE_NAME} is not running anywhere," \
                          "cleaning up to restart it globally if necessary"