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planetscale / vitess-operator

Kubernetes Operator for Vitess
Apache License 2.0
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Feature request: support controlled mysqld version upgrade with rollback #446

Closed maxenglander closed 7 months ago

maxenglander commented 1 year ago

Currently the way to upgrade from mysql 57 to 80 in the operator is to change mysqld image version. This causes operator to do a rolling upgrade of tablets. There's a lot that could go wrong here, and it would be nice if there were an option to do a controlled migration from 57 to 80.

One way this could work in theory is to create a new keyspace configured with mysql 80, and do a MoveTables from the 57 keyspace to the 80. This would allow carefully testing and validating that the upgrade succeeded before doing SwitchTraffic, and in theory would allow switching back to 57 if issues were discovered in 80 after SwitchTraffic (modulo reverse replication issues).

Assuming this idea is sound, what would be needed is to patch the operator to allow specifying mysqld image per keyspace. Currently this is not allowed, and the docs say: https://github.com/planetscale/vitess-operator/blob/5bf4279c968a365395e2ae8cf6c4cf61c172ad69/docs/api.md#L5280-L5283

deepthi commented 1 year ago

Currently the way to upgrade from mysql 57 to 80 in the operator is to change mysqld image version.

Just noting that this doesn't really work right now because the default collation in 8.0 does not exist in 5.7 and we are not setting an explicit collation in the mysql config file.

See https://github.com/planetscale/vitess-operator/issues/369