Databases on m5:

labsdbaccounts
mailman3
mailman3web
striker
test_labsdbaccounts
toolhub

When: Thursday 16th at 08:00 UTC
Impact: Writes will be disabled for around 1 minute.

Failover process

OLD MASTER: db1176

NEW MASTER: db1106

• Check configuration differences between new and old master

$ pt-config-diff h=db1106.eqiad.wmnet,F=/root/.my.cnf h=db1176.eqiad.wmnet,F=/root/.my.cnf

• Silence alerts on all hosts: sudo cookbook sre.hosts.downtime --minutes 60 -r "m5 master switch T331877" 'A:db-section-m5'
• Topology changes: move everything under db1106

db-switchover --timeout=15 --only-slave-move db1176.eqiad.wmnet db1106.eqiad.wmnet

• Disable puppet db1106 and db1176 sudo cumin 'db1106* or db1176*' 'disable-puppet "primary switchover T331877"'
• Merge gerrit: https://gerrit.wikimedia.org/r/899571
• Run puppet on dbproxy1017 and dbproxy1021 and check the config

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

• Start the failover: !log Failover m5 from db1176 to db1106 - T331877
• DB switchover

root@cumin1001:~/wmfmariadbpy/wmfmariadbpy# db-switchover --skip-slave-move db1176 db1106

• Reload haproxies (dbproxy1021 is the active one)

dbproxy1017:   systemctl reload haproxy && echo "show stat" | socat /run/haproxy/haproxy.sock stdio
dbproxy1021:   systemctl reload haproxy && echo "show stat" | socat /run/haproxy/haproxy.sock stdio

• kill connections on the old master (db1176)

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):db1106 and db1176 sudo cumin 'db1106* or db1176*' 'run-puppet-agent -e "primary switchover T331877"'
• Check affected services
• Clean orchestrator heartbeat to remove the old masters' one, otherwise Orchestrator will show lag: delete from heartbeat where server_id=171966607
• Upgrade db1176 to mariadb 10.6 and create another ticket for the switchover back: T322294