Databases on m5:

labsdbaccounts
mailman3
mailman3web
striker
test_labsdbaccounts
toolhub

When: 9th March - 14:00 UTC
Impact: Writes will be disabled for around 1 minute.

Failover process

OLD MASTER: db1132

NEW MASTER: db1107

• Check configuration differences between new and old master

$ pt-config-diff h=db1107.eqiad.wmnet,F=/root/.my.cnf h=db1132.eqiad.wmnet,F=/root/.my.cnf

• Silence alerts on all hosts
• Topology changes: move everything under db1107

db-switchover --timeout=15 --only-slave-move db1132.eqiad.wmnet db1107.eqiad.wmnet

• Disable puppet db1107 and db1132 puppet agent --disable "switchover to db1107 T302190 "
• Merge gerrit: https://gerrit.wikimedia.org/r/c/operations/puppet/+/768954
• Run puppet on dbproxy1017 and dbproxy1021 and check the config

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

• Start the failover: !log Failover m5 from db1132 to db1107 - T302190
• DB switchover

root@cumin1001:~/wmfmariadbpy/wmfmariadbpy# db-switchover --read-only-master --skip-slave-move db1132 db1107

• 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 (db1132)

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):db1107 and db1132 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=171970595
• Close this ticket and create a ticket to move db1132 somewhere else: db1132 will be moved to s1: T301879#7759181