Summary

Recommended for use with Vitess v16.0.0-rc1

Major Changes

EnforceSemiSync Removal

The config enforceSemiSync is removed from the VitessReplicationSpec. This configuration is no longer requied.
If the users want to configure semi-sync replication, they should set the durabilityPolicy config to semi_sync in the keyspace specification.
This change of not using enforceSemiSync should be done before upgrading to 2.9.0 version of the operator otherwise the configuration would not be accepted.

VTOrc becomes mandatory

VTOrc is now a required component of Vitess starting from v16. So, the vitess-operator will always run
a VTOrc instance for a keyspace, even if its configuration is unspecified.

MySQL Upgrade Path

With the latest version of Vitess (v16.0.0) the default MySQL version changed from 5.7 to 8.0.30.
Meaning that the vitess/lite:v15.0.2 and vitess/lite:v16.0.0 are running different MySQL major version.
If you want to remain on MySQL 5.7, we invite you to use vitess/lite:v16.0.0-mysql57.

Otherwise, if you were already running MySQL 8.0, with for instance vitess/lite:v15.0.2-mysql80, note that here the patch version of MySQL will also change between v15 and v16.
In v16.0.0 we are bumping the patch version of MySQL 80 from 8.0.23 to 8.0.30.
In order for you to correctly upgrade, there is a certain path to follow:

1. Add innodb_fast_shutdown=0 to your extra cnf in your YAML file.
2. Apply this file.
3. Wait for all the pods to be healthy.
4. Then change your YAML file to use the new Docker Images (vitess/lite:v16.0.0, defaults to mysql80).
5. Remove innodb_fast_shutdown=0 from your extra cnf in your YAML file.
6. Apply this file.