I'll start with an apology, I'm an Ops guy at heart, not a DBA, so I may use the wrong terminology, not in an effort to annoy, merely because I don't know any better.
OK, that over with, on to the question.
I've inherited a MySQL Cluster (using CentOS, Corosync, Pacemaker and MySQL Enterprise). It's a 2-node cluster, and it has a 3rd node (no MySQL, merely Corosync/Pacemaker) as a quorum node.
There are 2 VIP's set up on the cluster, one allocated to each box (Writer and Reader respective to Master/Slave).
This is all working fine, and I'm more (or less) happy with how it's set up and functioning. I should mention it's using GTID replication with full local storage (no SAN or DRBD).
Tacked onto the edge of this, is another node (MySQL, no Corosync/Pacemaker) This node is set up to slave from the Reader VIP that is allocated to the slave in the original cluster.
I've now been tasked with turning this extra backup into a Master/Slave cluster in it's own right, and I'm not sure where to begin with this. I have managed to get all 4 servers running as 2 clusters (independent to each other) but am failing to understand the Corosync/Pacemaker config I would need in order to make the Master of the second cluster become a Slave of the first cluster (or even if this is possible with the current software choices).
I'm just hoping someone out there has some experience on how to cluster clusters in this fashion and would be willing to point me in the correct direction.
Cluster 1 Cluster 2 ┌──────────────────────┐ ┌──────────────────────┐ │ Master Slave │ │ Master Slave │ │ ┌─────┐ ┌─────┐ │ │ ┌─────┐ ┌─────┐ │ │ │ │ Repl │ │ │ Reader VIP │ │ │ Repl │ │ │ │ │ DB1 ├──────┤ DB2 ├─────────────────────┤ DB3 ├──────┤ DB4 │ │ │ │ │ │ │ │ Replication │ │ │ │ │ │ │ └─────┘ └─────┘ │ │ └─────┘ └─────┘ │ └──────────────────────┘ └──────────────────────┘
I have access to all the config files and log files, but I wasn't sure which ones would count as relevant to this discussion (should it become a discussion).