Charmed MySQL

  • By Canonical Data Platform
  • Cloud
Channel Revision Published Runs on
8.0/stable 196 29 Sep 2023
Ubuntu 22.04
8.0/candidate 239 10 Jun 2024
Ubuntu 22.04
8.0/beta 239 10 Jun 2024
Ubuntu 22.04
8.0/edge 239 10 Jun 2024
Ubuntu 22.04
juju deploy mysql --channel 8.0/stable
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Platform:

Ubuntu
22.04

Switchover / Failover of Async replication

WARNING: it is an ‘8.0/edge’ article. Do NOT use it in production!
Contact Canonical Data Platform team if you are interested in the topic.

Pre-requisits

Make sure both Rome and Lisbon Clusters are deployed using the Async Deployment manual!

Switchover (safe)

Assuming Rome is currently Primary and you want to promote Lisbon to be new primary
(Rome will be converted to StandBy member):


juju run -m lisbon db2/leader promote-to-primary cluster-set-name=<cluster-set-119185404c15ba547eb5f0750a5c34b5>

where cluster-set-name is a mandatory option to avoid human mistakes.

The cluster-set-name can be set on deployment and retrieved using:


juju run -m rome db1/0 get-cluster-status cluster-set=true

...

domainname: cluster-set-bcba09a4d4feb2327fd6f8b0f4ac7a2c

...

Failover (forced)

Warning: this is a dangerous operation which can cause the split-brain situation. It should be executed if Primary cluster is no longer exist (lost) ONLY! Otherwise please use safe switchover procedure above!

Assuming Rome was a Primary (before we lost the cluster Rome) and you want to promote Lisbon to be the new primary:


juju run -m lisbon db2/leader promote-to-primary cluster-set-name=<cluster-set-bcba09a4d4feb2327fd6f8b0f4ac7a2c> force=True

It’s required to provide the cluster-set-name option as a foolproof method.

Warning: The force will cause the old primary to be invalidated.