Hi!

I have two Galera clusters of three nodes each, let's call them cluster A and cluster B.

Cluster B has one member set up as a slave to one of the members in cluster A.

The cluster B member that runs the slave protocol shows it's GTID matches that of the nodes in cluster A, but the other two nodes in cluster B (not running slaves themselves, but in the cluster with the node running as a slave) have GTIDs that are always 4 behind the other nodes.

So just to lay it out again:

A0 5-24-5 - master

A1 5-24-5 

A2 5-24-5

B0 5-24-5 - slave to A0

B1 5-24-1

B2 5-24-1

The  GTIDS stay 4 apart, and replication seems fine.   I add rows on any A cluster node and they show up in all three B nodes.  The GTID on the node running slave stays in sync with the A cluster.

The A0 cluster is set up using xtrabackupv2 for SST.

The A cluster is completely up before doing anything on the B cluster.

The B cluster is started like:

1. Start B0 as first node in the Galera cluster
2. mysqldump from A0 to B0 with --gtid.  https://gist.github.com/warnerpr/011cabb876600c33e5bee42d7d0b17d2
   
3. Master of B0 is set to A0
4. Slave is started on B0
5. B1 and B2 are started and set to join the existing cluster.