Change Details

**When:** During a pre-defined DBA maintenance windows. Tuesday 12th April at 06:00 AM UTC **Affected wikis:**: `commonswiki` `testcommonswiki` **Checklist:** NEW primary: db1160 OLD primary: db1138 [x] Check configuration differences between new and old primary: ``` sudo pt-config-diff --defaults-file /root/.my.cnf h=db1138.eqiad.wmnet h=db1160.eqiad.wmnet ``` **Failover prep:** [x] Silence alerts on all hosts: ``` sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s4 T304933" 'A:db-section-s4' ``` [x] Set NEW primary with weight 0 ``` sudo dbctl instance db1160 set-weight 0 sudo dbctl config commit -m "Set db1160 with weight 0 T304933" ``` [x] Topology changes, move all replicas under NEW primary ``` sudo db-switchover --timeout=15 --only-slave-move db1138 db1160 ``` [x] Disable puppet on both nodes ``` sudo cumin 'db1138* or db1160*' 'disable-puppet "primary switchover T304933"' ``` [x] Merge gerrit puppet change to promote NEW primary: https://gerrit.wikimedia.org/r/c/operations/puppet/+/778688/ **Failover:** [x] Log the failover: ``` !log Starting s4 eqiad failover from db1138 to db1160 - T304933 ``` [x] Set section read-only: ``` sudo dbctl --scope eqiad section s4 ro "Maintenance until 06:15 UTC - T304933" sudo dbctl config commit -m "Set s4 eqiad as read-only for maintenance - T304933" ``` [x] Check s4 is indeed read-only [x] Switch primaries: ``` sudo db-switchover --skip-slave-move db1138 db1160 echo "===== db1138 (OLD)"; sudo db-mysql db1138 -e 'show slave status\G' echo "===== db1160 (NEW)"; sudo db-mysql db1160 -e 'show slave status\G' ``` [x] Promote NEW primary in dbctl, and remove read-only ``` sudo dbctl --scope eqiad section s4 set-master db1160 sudo dbctl --scope eqiad section s4 rw sudo dbctl config commit -m "Promote db1160 to s4 primary and set section read-write T304933" ``` [x] Restart puppet on both hosts: ``` sudo cumin 'db1138* or db1160*' 'run-puppet-agent -e "primary switchover T304933"' ``` **Clean up tasks:** [x] Clean up heartbeat table(s): `delete from heartbeat.heartbeat where server_id=171978876` [x] change events for query killer: ``` events_coredb_master.sql on the new primary db1160 events_coredb_slave.sql on the new slave db1138 ``` [] Update DNS: https://gerrit.wikimedia.org/r/c/operations/dns/+/778689/ [] Update candidate primary dbctl and orchestrator notes ``` sudo dbctl instance db1138 set-candidate-master --section s4 true sudo dbctl instance db1160 set-candidate-master --section s4 false (dborch1001): sudo orchestrator-client -c untag -i db1160 --tag name=candidate (dborch1001): sudo orchestrator-client -c tag -i db1138 --tag name=candidate ``` [] Check zarcillo was updated ** db-switchover should do this. If it fails, do it manually: https://phabricator.wikimedia.org/P13956 [] (If needed): Depool db1138 for maintenance. ``` sudo dbctl instance db1138 depool sudo dbctl config commit -m "Depool db1138 T304933" ``` [] Apply outstanding schema changes to db1138 (if any) [] Update/resolve this ticket.

**When:** During a pre-defined DBA maintenance windows. Tuesday 12th April at 06:00 AM UTC **Affected wikis:**: `commonswiki` `testcommonswiki` **Checklist:** NEW primary: db1160 OLD primary: db1138 [x] Check configuration differences between new and old primary: ``` sudo pt-config-diff --defaults-file /root/.my.cnf h=db1138.eqiad.wmnet h=db1160.eqiad.wmnet ``` **Failover prep:** [x] Silence alerts on all hosts: ``` sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s4 T304933" 'A:db-section-s4' ``` [x] Set NEW primary with weight 0 ``` sudo dbctl instance db1160 set-weight 0 sudo dbctl config commit -m "Set db1160 with weight 0 T304933" ``` [x] Topology changes, move all replicas under NEW primary ``` sudo db-switchover --timeout=15 --only-slave-move db1138 db1160 ``` [x] Disable puppet on both nodes ``` sudo cumin 'db1138* or db1160*' 'disable-puppet "primary switchover T304933"' ``` [x] Merge gerrit puppet change to promote NEW primary: https://gerrit.wikimedia.org/r/c/operations/puppet/+/778688/ **Failover:** [x] Log the failover: ``` !log Starting s4 eqiad failover from db1138 to db1160 - T304933 ``` [x] Set section read-only: ``` sudo dbctl --scope eqiad section s4 ro "Maintenance until 06:15 UTC - T304933" sudo dbctl config commit -m "Set s4 eqiad as read-only for maintenance - T304933" ``` [x] Check s4 is indeed read-only [x] Switch primaries: ``` sudo db-switchover --skip-slave-move db1138 db1160 echo "===== db1138 (OLD)"; sudo db-mysql db1138 -e 'show slave status\G' echo "===== db1160 (NEW)"; sudo db-mysql db1160 -e 'show slave status\G' ``` [x] Promote NEW primary in dbctl, and remove read-only ``` sudo dbctl --scope eqiad section s4 set-master db1160 sudo dbctl --scope eqiad section s4 rw sudo dbctl config commit -m "Promote db1160 to s4 primary and set section read-write T304933" ``` [x] Restart puppet on both hosts: ``` sudo cumin 'db1138* or db1160*' 'run-puppet-agent -e "primary switchover T304933"' ``` **Clean up tasks:** [x] Clean up heartbeat table(s): `delete from heartbeat.heartbeat where server_id=171978876` [x] change events for query killer: ``` events_coredb_master.sql on the new primary db1160 events_coredb_slave.sql on the new slave db1138 ``` [x] Update DNS: https://gerrit.wikimedia.org/r/c/operations/dns/+/778689/ [x] Update candidate primary dbctl and orchestrator notes ``` sudo dbctl instance db1138 set-candidate-master --section s4 true sudo dbctl instance db1160 set-candidate-master --section s4 false (dborch1001): sudo orchestrator-client -c untag -i db1160 --tag name=candidate (dborch1001): sudo orchestrator-client -c tag -i db1138 --tag name=candidate ``` [] Check zarcillo was updated ** db-switchover should do this. If it fails, do it manually: https://phabricator.wikimedia.org/P13956 [] (If needed): Depool db1138 for maintenance. ``` sudo dbctl instance db1138 depool sudo dbctl config commit -m "Depool db1138 T304933" ``` [] Apply outstanding schema changes to db1138 (if any) [] Update/resolve this ticket.