Change Details

**When:** During a pre-defined DBA maintenance windows **Affected wikis:**: https://noc.wikimedia.org/conf/highlight.php?file=dblists/s8.dblist **Checklist:** NEW primary: db1209 OLD primary: db1126 [x] Check configuration differences between new and old primary: ``` sudo pt-config-diff --defaults-file /root/.my.cnf h=db1126.eqiad.wmnet h=db1209.eqiad.wmnet ``` **Failover prep:** [x] Silence alerts on all hosts: ``` sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s8 T349077" 'A:db-section-s8' ``` [x] Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present). ``` sudo dbctl instance db1209 set-weight 0 sudo dbctl config commit -m "Set db1209 with weight 0 T349077" ``` [x] Topology changes, move all replicas under NEW primary ``` sudo db-switchover --timeout=25 --replicating-master --read-only-master --only-slave-move db1126 db1209 ``` [x] Disable puppet on both nodes ``` sudo cumin 'db1126* or db1209*' 'disable-puppet "primary switchover T349077"' ``` [] Merge gerrit puppet change to promote NEW primary: FIXME **Failover:** [] Log the failover: ``` !log Starting s8 eqiad failover from db1126 to db1209 - T349077 ``` [] Switch primaries: ``` sudo db-switchover --replicating-master --read-only-master --skip-slave-move db1126 db1209 echo "===== db1126 (OLD)"; sudo db-mysql db1126 -e 'show slave status\G' echo "===== db1209 (NEW)"; sudo db-mysql db1209 -e 'show slave status\G' ``` [] Promote NEW primary in dbctl ``` sudo dbctl --scope eqiad section s8 set-master db1209 sudo dbctl config commit -m "Promote db1209 to s8 primary T349077" ``` [] Restart puppet on both hosts: ``` sudo cumin 'db1126* or db1209*' 'run-puppet-agent -e "primary switchover T349077"' ``` **Clean up tasks:** [] Clean up heartbeat table(s). ``` sudo db-mysql db1209 heartbeat -e "delete from heartbeat where file like 'db1126%';" ``` [] change events for query killer: ``` events_coredb_master.sql on the new primary db1209 events_coredb_slave.sql on the new slave db1126 ``` [] Update candidate primary dbctl and orchestrator notes ``` sudo dbctl instance db1126 set-candidate-master --section s8 true sudo dbctl instance db1209 set-candidate-master --section s8 false (dborch1001): sudo orchestrator-client -c untag -i db1209 --tag name=candidate (dborch1001): sudo orchestrator-client -c tag -i db1126 --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 db1215 zarcillo -e "select * from masters where section = 's8';" ``` [] (If needed): Depool db1126 for maintenance. ``` sudo dbctl instance db1126 depool sudo dbctl config commit -m "Depool db1126 T349077" ``` [] Change db1126 weight to mimic the previous weight db1209: ``` sudo dbctl instance db1126 edit ``` [] Apply outstanding schema changes to db1126 (if any) [] set db1126 weight to 275 (initial weight of db1126) [] Update/resolve this ticket.

**When:** During a pre-defined DBA maintenance windows **Affected wikis:**: https://noc.wikimedia.org/conf/highlight.php?file=dblists/s8.dblist **Checklist:** NEW primary: db1209 OLD primary: db1126 [x] Check configuration differences between new and old primary: ``` sudo pt-config-diff --defaults-file /root/.my.cnf h=db1126.eqiad.wmnet h=db1209.eqiad.wmnet ``` **Failover prep:** [x] Silence alerts on all hosts: ``` sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s8 T349077" 'A:db-section-s8' ``` [x] Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present). ``` sudo dbctl instance db1209 set-weight 0 sudo dbctl config commit -m "Set db1209 with weight 0 T349077" ``` [x] Topology changes, move all replicas under NEW primary ``` sudo db-switchover --timeout=25 --replicating-master --read-only-master --only-slave-move db1126 db1209 ``` [x] Disable puppet on both nodes ``` sudo cumin 'db1126* or db1209*' 'disable-puppet "primary switchover T349077"' ``` [x] Merge gerrit puppet change to promote NEW primary: FIXME **Failover:** [] Log the failover: ``` !log Starting s8 eqiad failover from db1126 to db1209 - T349077 ``` [] Switch primaries: ``` sudo db-switchover --replicating-master --read-only-master --skip-slave-move db1126 db1209 echo "===== db1126 (OLD)"; sudo db-mysql db1126 -e 'show slave status\G' echo "===== db1209 (NEW)"; sudo db-mysql db1209 -e 'show slave status\G' ``` [] Promote NEW primary in dbctl ``` sudo dbctl --scope eqiad section s8 set-master db1209 sudo dbctl config commit -m "Promote db1209 to s8 primary T349077" ``` [] Restart puppet on both hosts: ``` sudo cumin 'db1126* or db1209*' 'run-puppet-agent -e "primary switchover T349077"' ``` **Clean up tasks:** [] Clean up heartbeat table(s). ``` sudo db-mysql db1209 heartbeat -e "delete from heartbeat where file like 'db1126%';" ``` [] change events for query killer: ``` events_coredb_master.sql on the new primary db1209 events_coredb_slave.sql on the new slave db1126 ``` [] Update candidate primary dbctl and orchestrator notes ``` sudo dbctl instance db1126 set-candidate-master --section s8 true sudo dbctl instance db1209 set-candidate-master --section s8 false (dborch1001): sudo orchestrator-client -c untag -i db1209 --tag name=candidate (dborch1001): sudo orchestrator-client -c tag -i db1126 --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 db1215 zarcillo -e "select * from masters where section = 's8';" ``` [] (If needed): Depool db1126 for maintenance. ``` sudo dbctl instance db1126 depool sudo dbctl config commit -m "Depool db1126 T349077" ``` [] Change db1126 weight to mimic the previous weight db1209: ``` sudo dbctl instance db1126 edit ``` [] Apply outstanding schema changes to db1126 (if any) [] set db1126 weight to 275 (initial weight of db1126) [] Update/resolve this ticket.