Databases on m1:

+--------------------+
| Database           |
+--------------------+
| bacula9            |
| cas                |
| cas_staging        |
| dbbackups          |
| etherpadlite       |
| heartbeat          |
| information_schema |
| librenms           |
| mysql              |
| percona            |
| performance_schema |
| pki                |
| racktables         |
| rddmarc            |
| rt                 |
| sys                |
+--------------------+
16 rows in set (0.002 sec)

When: Soon
Impact: Writes will be disabled for around 1 minute.

Failover process

OLD MASTER: db1128

NEW MASTER: db1164

• Check configuration differences between new and old master

$ pt-config-diff h=db1128.eqiad.wmnet,F=/root/.my.cnf h=db1164.eqiad.wmnet,F=/root/.my.cnf

• Silence alerts on all hosts
• Add db1164 as a secondary on the proxies- Merge and deploy https://gerrit.wikimedia.org/r/c/operations/puppet/+/799915
• Topology changes: move everything under db1164

db-switchover --timeout=15 --only-slave-move db1128.eqiad.wmnet db1164.eqiad.wmnet

• Disable puppet db1128 and db1164 disable-puppet "switchover T309296"
• Merge gerrit: https://gerrit.wikimedia.org/r/c/operations/puppet/+/799901
• Run puppet on dbproxy1012 and dbproxy1014 and check the config

run-puppet-agent && cat /etc/haproxy/conf.d/db-master.cfg

• Start the failover: !log Failover m1 from db1128 to db1164 - T309296
• DB switchover

root@cumin1001:~/wmfmariadbpy/wmfmariadbpy# db-switchover --read-only-master --skip-slave-move db1128 db1164

• Reload haproxies (dbproxy1012 is the active one)

dbproxy1012:   systemctl reload haproxy && echo "show stat" | socat /run/haproxy/haproxy.sock stdio
dbproxy1014:   systemctl reload haproxy && echo "show stat" | socat /run/haproxy/haproxy.sock stdio

• kill connections on the old master (db1128)

pt-kill --print --kill --victims all --match-all F=/dev/null,S=/run/mysqld/mysqld.sock

• Restart puppet on old and new masters (for heartbeat):db1128 and db1164 puppet agent --enable && puppet agent -tv
• Check affected services
• Clean orchestrator heartbeat to remove the old masters' one, otherwise Orchestrator will show lag: delete from heartbeat where server_id= 171966562
• If everything looks good, afterwards: Move backups to use the new host: Merge https://gerrit.wikimedia.org/r/c/operations/puppet/+/799894
• Close this ticket and create a ticket to move db1128 to s1 T309303