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Switchover s7 codfw master (db2121 -> db2118)
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Description

Checklist:

NEW primary: db2118
OLD primary: db2121

  • Check configuration differences between new and old primary:
sudo pt-config-diff --defaults-file /root/.my.cnf h=db2121.codfw.wmnet h=db2118.codfw.wmnet

Failover prep:

  • Silence alerts on all hosts:
sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover s7 T318888" 'A:db-section-s7'
  • Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present).
sudo dbctl instance db2118 set-weight 0
sudo dbctl config commit -m "Set db2118 with weight 0 T318888"
  • Topology changes, move all replicas under NEW primary
sudo db-switchover --replicating-master --read-only-master --timeout=25 --only-slave-move db2121 db2118
  • Disable puppet on both nodes
sudo cumin 'db2121* or db2118*' 'disable-puppet "primary switchover T318888"'

Failover:

  • Log the failover:
!log Starting s7 codfw failover from db2121 to db2118 - T318888
  • Switch primaries:
sudo db-switchover --replicating-master --read-only-master --skip-slave-move db2121 db2118
echo "===== db2121 (OLD)"; sudo db-mysql db2121 -e 'show slave status\G'
echo "===== db2118 (NEW)"; sudo db-mysql db2118 -e 'show slave status\G'
  • Promote NEW primary in dbctl, and remove read-only
sudo dbctl --scope codfw section s7 set-master db2118
sudo dbctl config commit -m "Promote db2118 to s7 primary and set section read-write T318888"
  • Restart puppet on both hosts:
sudo cumin 'db2121* or db2118*' 'run-puppet-agent -e "primary switchover T318888"'

Clean up tasks:

  • Clean up heartbeat table(s).
sudo db-mysql db2118 heartbeat -e "delete from heartbeat where file like 'db2121%';"
  • change events for query killer:
events_coredb_master.sql on the new primary db2118
events_coredb_slave.sql on the new slave db2121
  • Update candidate primary dbctl and orchestrator notes
sudo dbctl instance db2121 set-candidate-master --section s7 true
sudo dbctl instance db2118 set-candidate-master --section s7 false
(dborch1001): sudo orchestrator-client -c untag -i db2118 --tag name=candidate
(dborch1001): sudo orchestrator-client -c tag -i db2121 --tag name=candidate
sudo db-mysql db1115 zarcillo -e "select * from masters where section = 's7';"
  • (If needed): Depool db2121 for maintenance.
sudo dbctl instance db2121 depool
sudo dbctl config commit -m "Depool db2121 T318888"
  • Change db2121 weight to mimic the previous weight db2118:
sudo dbctl instance db2121 edit
  • Update/resolve this ticket.

Event Timeline

Mentioned in SAL (#wikimedia-operations) [2022-09-29T05:44:47Z] <marostegui@cumin1001> START - Cookbook sre.hosts.downtime for 1:00:00 on 30 hosts with reason: Primary switchover s7 T318888

Mentioned in SAL (#wikimedia-operations) [2022-09-29T05:45:08Z] <marostegui@cumin1001> END (PASS) - Cookbook sre.hosts.downtime (exit_code=0) for 1:00:00 on 30 hosts with reason: Primary switchover s7 T318888

Mentioned in SAL (#wikimedia-operations) [2022-09-29T05:45:11Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Set db2118 with weight 0 T318888', diff saved to https://phabricator.wikimedia.org/P35119 and previous config saved to /var/cache/conftool/dbconfig/20220929-054509-root.json

Mentioned in SAL (#wikimedia-operations) [2022-09-29T05:45:43Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Depool db2118 from API T318888', diff saved to https://phabricator.wikimedia.org/P35120 and previous config saved to /var/cache/conftool/dbconfig/20220929-054542-root.json

Marostegui renamed this task from Switchover s7 codfw master (db2110 -> db2118) to Switchover s7 codfw master (db2121 -> db2118).Sep 29 2022, 5:45 AM
Marostegui triaged this task as Medium priority.
Marostegui added a project: DBA.
Marostegui updated the task description. (Show Details)

Change 836602 had a related patch set uploaded (by Marostegui; author: Marostegui):

[operations/puppet@production] mariadb: Promote db2118 to s7 codfw master

https://gerrit.wikimedia.org/r/836602

Change 836602 merged by Marostegui:

[operations/puppet@production] mariadb: Promote db2118 to s7 codfw master

https://gerrit.wikimedia.org/r/836602

Mentioned in SAL (#wikimedia-operations) [2022-09-29T06:03:31Z] <marostegui> Starting s7 codfw failover from db2121 to db2118 - T318888

Mentioned in SAL (#wikimedia-operations) [2022-09-29T06:04:25Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Promote db2118 to s7 primary and set section read-write T318888', diff saved to https://phabricator.wikimedia.org/P35122 and previous config saved to /var/cache/conftool/dbconfig/20220929-060425-root.json

Mentioned in SAL (#wikimedia-operations) [2022-09-29T06:05:32Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Depool db2121 T318888', diff saved to https://phabricator.wikimedia.org/P35123 and previous config saved to /var/cache/conftool/dbconfig/20220929-060532-root.json

Marostegui updated the task description. (Show Details)

Done