To be able to do that, we need to get hold of the MXS_MONITORED_SERVER
corresponding to the SERVER specified as the new master.
So, instead of just return a boolean indicating whether the server was
found or not we return the MXS_MONITORED_SERVER pointer.
Switchover expects one or two servers as argument, one (the new
master) if there is no master and two (the new master, and the
current master) if there currently is a master.
The procedure is as follows:
- Stop monitor
- Check that provided arguments are reasonable.
- If there is no master currently, then only one argument is
accepted.
- If there is a master, then it must also be specified.
This is to prevent pathological cases where the situation has
changed after the admin has issued the switchover command.
- Check the failover mode and disable it.
- Perform the failover.
- If succeeded, enable failover if it was.
- If it failed, if failover was enabled, do not enable it and log
an alert. If failover was not enabled, just log an error.
