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Switchover x1 master (db1120 -> db1103)
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Description

When: Thursday 26th at 07:00 AM UTC

Prerequisites: https://wikitech.wikimedia.org/wiki/MariaDB/Primary_switchover

  • Team calendar invite

Affected wikis:: All in x1

Checklist:

NEW primary: db1103
OLD primary: db1120

  • Check configuration differences between new and old primary:
sudo pt-config-diff --defaults-file /root/.my.cnf h=db1120.eqiad.wmnet h=db1103.eqiad.wmnet

Failover prep:

  • Silence alerts on all hosts:
sudo cookbook sre.hosts.downtime --hours 1 -r "Primary switchover x1 T327861" 'A:db-section-x1'
  • Set NEW primary with weight 0 (and depool it from API or vslow/dump groups if it is present).
sudo dbctl instance db1103 set-weight 0
sudo dbctl config commit -m "Set db1103 with weight 0 T327861"
  • Topology changes, move all replicas under NEW primary
sudo db-switchover --timeout=25 --only-slave-move db1120 db1103
  • Disable puppet on both nodes
sudo cumin 'db1120* or db1103*' 'disable-puppet "primary switchover T327861"'

Failover:

  • Log the failover:
!log Starting x1 eqiad failover from db1120 to db1103 - T327861
  • Switch primaries:
sudo db-switchover --skip-slave-move db1120 db1103
echo "===== db1120 (OLD)"; sudo db-mysql db1120 -e 'show slave status\G'
echo "===== db1103 (NEW)"; sudo db-mysql db1103 -e 'show slave status\G'
  • Promote NEW primary in dbctl, and remove read-only
sudo dbctl --scope eqiad section x1 set-master db1103
sudo dbctl config commit -m "Promote db1103 to x1 primary and set section read-write T327861"
  • Restart puppet on both hosts:
sudo cumin 'db1120* or db1103*' 'run-puppet-agent -e "primary switchover T327861"'

Clean up tasks:

  • Clean up heartbeat table(s).
sudo db-mysql db1103 heartbeat -e "delete from heartbeat where file like 'db1120%';"
  • change events for query killer:
events_coredb_master.sql on the new primary db1103
events_coredb_slave.sql on the new slave db1120
sudo dbctl instance db1120 set-candidate-master --section x1 true
sudo dbctl instance db1103 set-candidate-master --section x1 false
(dborch1001): sudo orchestrator-client -c untag -i db1103 --tag name=candidate
(dborch1001): sudo orchestrator-client -c tag -i db1120 --tag name=candidate
sudo db-mysql db1115 zarcillo -e "select * from masters where section = 'x1';"
  • (If needed): Depool db1120 for maintenance.
sudo dbctl instance db1120 depool
sudo dbctl config commit -m "Depool db1120 T327861"
  • Change db1120 weight to mimic the previous weight db1103:
sudo dbctl instance db1120 edit
  • Update/resolve this ticket.

Event Timeline

Change 882785 had a related patch set uploaded (by Gerrit maintenance bot; author: Gerrit maintenance bot):

[operations/puppet@production] mariadb: Promote db1103 to x1 master

https://gerrit.wikimedia.org/r/882785

Change 883506 had a related patch set uploaded (by Gerrit maintenance bot; author: Gerrit maintenance bot):

[operations/dns@master] wmnet: Update x1-master alias

https://gerrit.wikimedia.org/r/883506

Marostegui triaged this task as Medium priority.
Marostegui moved this task from Triage to In progress on the DBA board.
Marostegui added a subscriber: Marostegui.

This will happen Thursday 26th at 08:00 AM UTC

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

Mentioned in SAL (#wikimedia-operations) [2023-01-26T06:16:44Z] <marostegui@cumin1001> START - Cookbook sre.hosts.downtime for 1:00:00 on 10 hosts with reason: Primary switchover x1 T327861

Marostegui added a parent task: Restricted Task.Thu, Jan 26, 6:17 AM

Mentioned in SAL (#wikimedia-operations) [2023-01-26T06:17:03Z] <marostegui@cumin1001> END (PASS) - Cookbook sre.hosts.downtime (exit_code=0) for 1:00:00 on 10 hosts with reason: Primary switchover x1 T327861

Mentioned in SAL (#wikimedia-operations) [2023-01-26T06:17:52Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Set db1103 with weight 0 T327861', diff saved to https://phabricator.wikimedia.org/P43350 and previous config saved to /var/cache/conftool/dbconfig/20230126-061751-root.json

Change 882785 merged by Marostegui:

[operations/puppet@production] mariadb: Promote db1103 to x1 master

https://gerrit.wikimedia.org/r/882785

Change 883694 had a related patch set uploaded (by Marostegui; author: Marostegui):

[operations/puppet@production] db1120: Disable notifications

https://gerrit.wikimedia.org/r/883694

Change 883694 merged by Marostegui:

[operations/puppet@production] db1120: Disable notifications

https://gerrit.wikimedia.org/r/883694

Mentioned in SAL (#wikimedia-operations) [2023-01-26T07:00:08Z] <marostegui> Starting x1 eqiad failover from db1120 to db1103 - T327861

Mentioned in SAL (#wikimedia-operations) [2023-01-26T07:00:36Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Promote db1103 to x1 primary and set section read-write T327861', diff saved to https://phabricator.wikimedia.org/P43351 and previous config saved to /var/cache/conftool/dbconfig/20230126-070035-marostegui.json

Mentioned in SAL (#wikimedia-operations) [2023-01-26T07:01:59Z] <marostegui@cumin1001> dbctl commit (dc=all): 'Depool db1120 T327861', diff saved to https://phabricator.wikimedia.org/P43352 and previous config saved to /var/cache/conftool/dbconfig/20230126-070158-root.json

Change 883506 merged by Marostegui:

[operations/dns@master] wmnet: Update x1-master alias

https://gerrit.wikimedia.org/r/883506

Marostegui updated the task description. (Show Details)

This is done