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Switchover es4 master (es2021 -> es2020)
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Description

When: Anytime - no in use

Checklist:

NEW primary: es2020
OLD primary: es2021

  • Check configuration differences between new and old primary:
sudo pt-config-diff --defaults-file /root/.my.cnf h=es2021.codfw.wmnet h=es2020.codfw.wmnet

Failover prep:

  • Silence alerts on all hosts:
sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover es4 T337203" 'A:db-section-es4'
  • Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present).
sudo dbctl instance es2020 set-weight 0
sudo dbctl config commit -m "Set es2020 with weight 0 T337203"
  • Topology changes, move all replicas under NEW primary
sudo db-switchover --read-only-master --replicating-master --timeout=25 --only-slave-move es2021 es2020
  • Disable puppet on both nodes
sudo cumin 'es2021* or es2020*' 'disable-puppet "primary switchover T337203"'

Failover:

  • Log the failover:
!log Starting es4 codfw failover from es2021 to es2020 - T337203
  • Switch primaries:
sudo db-switchover --read-only-master --replicating-master  --skip-slave-move es2021 es2020
echo "===== es2021 (OLD)"; sudo db-mysql es2021 -e 'show slave status\G'
echo "===== es2020 (NEW)"; sudo db-mysql es2020 -e 'show slave status\G'
  • Promote NEW primary in dbctl, and remove read-only
sudo dbctl --scope codfw section es4 set-master es2020
sudo dbctl --scope codfw section es4 rw
sudo dbctl config commit -m "Promote es2020 to es4 primary and set section read-write T337203"
  • Restart puppet on both hosts:
sudo cumin 'es2021* or es2020*' 'run-puppet-agent -e "primary switchover T337203"'

Clean up tasks:

  • Clean up heartbeat table(s).
sudo db-mysql es2020 heartbeat -e "delete from heartbeat where file like 'es2021%';"
  • change events for query killer:
events_coredb_master.sql on the new primary es2020
events_coredb_slave.sql on the new slave es2021
  • Update candidate primary dbctl and orchestrator notes
sudo dbctl instance es2021 set-candidate-master --section es4 true
sudo dbctl instance es2020 set-candidate-master --section es4 false
(dborch1001): sudo orchestrator-client -c untag -i es2020 --tag name=candidate
(dborch1001): sudo orchestrator-client -c tag -i es2021 --tag name=candidate
sudo db-mysql db1215 zarcillo -e "select * from masters where section = 'es4';"
  • (If needed): Depool es2021 for maintenance.
sudo dbctl instance es2021 depool
sudo dbctl config commit -m "Depool es2021 T337203"
  • Change es2021 weight to mimic the previous weight es2020:
sudo dbctl instance es2021 edit
  • Update/resolve this ticket.

Event Timeline

Marostegui triaged this task as Medium priority.May 22 2023, 5:26 AM
Marostegui updated the task description. (Show Details)
Marostegui moved this task from Triage to In progress on the DBA board.

Mentioned in SAL (#wikimedia-operations) [2023-05-22T05:29:22Z] <marostegui@cumin1001> START - Cookbook sre.hosts.downtime for 1:00:00 on 6 hosts with reason: Primary switchover es4 T337203

Mentioned in SAL (#wikimedia-operations) [2023-05-22T05:29:38Z] <marostegui@cumin1001> END (PASS) - Cookbook sre.hosts.downtime (exit_code=0) for 1:00:00 on 6 hosts with reason: Primary switchover es4 T337203

Mentioned in SAL (#wikimedia-operations) [2023-05-22T05:29:43Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Set es2020 with weight 0 T337203', diff saved to https://phabricator.wikimedia.org/P48410 and previous config saved to /var/cache/conftool/dbconfig/20230522-052938-root.json

Change 921772 had a related patch set uploaded (by Marostegui; author: Marostegui):

[operations/puppet@production] mariadb: Promote es2020 to es4 master

https://gerrit.wikimedia.org/r/921772

Mentioned in SAL (#wikimedia-operations) [2023-05-22T05:34:21Z] <marostegui> Starting es4 codfw failover from es2021 to es2020 - T337203

Change 921772 merged by Marostegui:

[operations/puppet@production] mariadb: Promote es2020 to es4 master

https://gerrit.wikimedia.org/r/921772

Mentioned in SAL (#wikimedia-operations) [2023-05-22T05:37:05Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Depool es2021 T337203', diff saved to https://phabricator.wikimedia.org/P48412 and previous config saved to /var/cache/conftool/dbconfig/20230522-053705-marostegui.json

Marostegui updated the task description. (Show Details)
Marostegui updated the task description. (Show Details)

This was done, I am going to upgrade es2021 and reboot it.