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Switchover m3 (phabricator) master db1072 to db1128
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We will be switching over our primary database master for m3 (phabricator) which is db1072 to db1128.

db1072 is and old and out of warranty host that needs to be decommissioned.

When: Thursday 25 July - 05:30 - 06:00 AM UTC.
Impact: Writes will be blocked. Reads will remain unaffected.

The procedure will be as follows:

  • @Marostegui will do all the pre-switchover steps (including topology changes)
  • @mmodell will set up read-only for phabricator
  • @Marostegui will execute the switchover to promote db1128 to master and db1072 to slave
  • @Marostegui will reload haproxies to make db1128 primary on the proxy configuration
  • If everything looks good:
  • @mmodell to set up phabricator as read-write again.

We don't expect to use the full 30 minutes read-only window if everything goes fine.
The database switchover+proxy reload part should only take a few seconds. So I would expect just a few minutes of read-only as we need to get also phabricator read-only ON and OFF from the application layer.

Event Timeline

Marostegui triaged this task as Medium priority.Jul 17 2019, 6:00 AM

Change 523941 had a related patch set uploaded (by Marostegui; owner: Marostegui):
[operations/puppet@production] mariadb: Promote db1128 as master for m3

Mentioned in SAL (#wikimedia-operations) [2019-07-25T04:51:54Z] <marostegui> Start pre-failover steps on m3 T228243

Change 523941 merged by Marostegui:
[operations/puppet@production] mariadb: Promote db1128 as master for m3

This has been done.
Phabricator read only start: 05:30:44
Phabricator read only stop: 05:31:37

Total read-only time: 53 seconds

Thanks @mmodell for being around to handle the phabricator side of things.