Change Details

**When:** During a pre-defined DBA maintenance windows **Affected wikis:**: https://noc.wikimedia.org/conf/highlight.php?file=dblists/s5.dblist **Checklist:** NEW primary: db2123 OLD primary: db2113 [] Check configuration differences between new and old primary: ``` sudo pt-config-diff --defaults-file /root/.my.cnf h=db2113.codfw.wmnet h=db2123.codfw.wmnet ``` **Failover prep:** [] Silence alerts on all hosts: ``` sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s5 T327611" 'A:db-section-s5' ``` [] Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present). ``` sudo dbctl instance db2123 set-weight 0 sudo dbctl config commit -m "Set db2123 with weight 0 T327611" ``` [] Topology changes, move all replicas under NEW primary ``` sudo db-switchover --timeout=25 --replicating-master --read-only-master --only-slave-move db2113 db2123 ``` [] Disable puppet on both nodes ``` sudo cumin 'db2113* or db2123*' 'disable-puppet "primary switchover T327611"' ``` [] Merge gerrit puppet change to promote NEW primary: FIXME **Failover:** [] Log the failover: ``` !log Starting s5 codfw failover from db2113 to db2123 - T327611 ``` [] Switch primaries: ``` sudo db-switchover --replicating-master --read-only-master --skip-slave-move db2113 db2123 echo "===== db2113 (OLD)"; sudo db-mysql db2113 -e 'show slave status\G' echo "===== db2123 (NEW)"; sudo db-mysql db2123 -e 'show slave status\G' ``` [] Promote NEW primary in dbctl ``` sudo dbctl --scope codfw section s5 set-master db2123 sudo dbctl config commit -m "Promote db2123 to s5 primary T327611" ``` [] Restart puppet on both hosts: ``` sudo cumin 'db2113* or db2123*' 'run-puppet-agent -e "primary switchover T327611"' ``` **Clean up tasks:** [] Clean up heartbeat table(s). ``` sudo db-mysql db2123 heartbeat -e "delete from heartbeat where file like 'db2113%';" ``` [] change events for query killer: ``` events_coredb_master.sql on the new primary db2123 events_coredb_slave.sql on the new slave db2113 ``` [] Update candidate primary dbctl and orchestrator notes ``` sudo dbctl instance db2113 set-candidate-master --section s5 true sudo dbctl instance db2123 set-candidate-master --section s5 false (dborch1001): sudo orchestrator-client -c untag -i db2123 --tag name=candidate (dborch1001): sudo orchestrator-client -c tag -i db2113 --tag name=candidate ``` [] Check zarcillo was updated ** db-switchover should do this. If it fails, do it manually: https://phabricator.wikimedia.org/P13956 ``` sudo db-mysql db1115 zarcillo -e "select * from masters where section = 's5';" ``` [] (If needed): Depool db2113 for maintenance. ``` sudo dbctl instance db2113 depool sudo dbctl config commit -m "Depool db2113 T327611" ``` [] Change db2113 weight to mimic the previous weight db2123: ``` sudo dbctl instance db2113 edit ``` [] Apply outstanding schema changes to db2113 (if any) [] Update/resolve this ticket.

**When:** During a pre-defined DBA maintenance windows **Affected wikis:**: https://noc.wikimedia.org/conf/highlight.php?file=dblists/s5.dblist **Checklist:** NEW primary: db2123 OLD primary: db2113 [x] Check configuration differences between new and old primary: ``` sudo pt-config-diff --defaults-file /root/.my.cnf h=db2113.codfw.wmnet h=db2123.codfw.wmnet ``` **Failover prep:** [x] Silence alerts on all hosts: ``` sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s5 T327611" 'A:db-section-s5' ``` [x] Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present). ``` sudo dbctl instance db2123 set-weight 0 sudo dbctl config commit -m "Set db2123 with weight 0 T327611" ``` [x] Topology changes, move all replicas under NEW primary ``` sudo db-switchover --timeout=25 --replicating-master --read-only-master --only-slave-move db2113 db2123 ``` [x] Disable puppet on both nodes ``` sudo cumin 'db2113* or db2123*' 'disable-puppet "primary switchover T327611"' ``` [x] Merge gerrit puppet change to promote NEW primary: FIXME **Failover:** [x] Log the failover: ``` !log Starting s5 codfw failover from db2113 to db2123 - T327611 ``` [x] Switch primaries: ``` sudo db-switchover --replicating-master --read-only-master --skip-slave-move db2113 db2123 echo "===== db2113 (OLD)"; sudo db-mysql db2113 -e 'show slave status\G' echo "===== db2123 (NEW)"; sudo db-mysql db2123 -e 'show slave status\G' ``` [x] Promote NEW primary in dbctl ``` sudo dbctl --scope codfw section s5 set-master db2123 sudo dbctl config commit -m "Promote db2123 to s5 primary T327611" ``` [x] Restart puppet on both hosts: ``` sudo cumin 'db2113* or db2123*' 'run-puppet-agent -e "primary switchover T327611"' ``` **Clean up tasks:** [x] Clean up heartbeat table(s). ``` sudo db-mysql db2123 heartbeat -e "delete from heartbeat where file like 'db2113%';" ``` [x] change events for query killer: ``` events_coredb_master.sql on the new primary db2123 events_coredb_slave.sql on the new slave db2113 ``` [] Update candidate primary dbctl and orchestrator notes ``` sudo dbctl instance db2113 set-candidate-master --section s5 true sudo dbctl instance db2123 set-candidate-master --section s5 false (dborch1001): sudo orchestrator-client -c untag -i db2123 --tag name=candidate (dborch1001): sudo orchestrator-client -c tag -i db2113 --tag name=candidate ``` [x] Check zarcillo was updated ** db-switchover should do this. If it fails, do it manually: https://phabricator.wikimedia.org/P13956 ``` sudo db-mysql db1115 zarcillo -e "select * from masters where section = 's5';" ``` [x] (If needed): Depool db2113 for maintenance. ``` sudo dbctl instance db2113 depool sudo dbctl config commit -m "Depool db2113 T327611" ``` [x] Change db2113 weight to mimic the previous weight db2123: ``` sudo dbctl instance db2113 edit ``` [x] Apply outstanding schema changes to db2113 (if any) [x] Update/resolve this ticket.