Switchover Support

It would be beneficial to be able to perform switchover through MaxScale, whether or not it is configured to perform failover.

• Even if not initialting failover, MaxScale can still benefit from knowing whether switchover will be performed, e.g. by internally behaving as if the old master had been put in maintenance mode, queing new connection attempts until the new master is up again, etc.
• If MaxScale is initiating failover, then it needs to turn off that behaviour while switchover is taking place, as otherwise the switchover and the failover may interfere with each other.

It would of course be possible to

• connect to to MaxScale,
• turn off the relevant monitor,
• perform the switchover, and
• turn on the relevant monitor again

but from an end-user point of view it is simpler if it is possible to simply initiate the switchover through MaxScale and it takes care of everything.