If you are using SElinux, you should know that it’s advised to disable it to avoid issue with PXC. Generally the communication between your nodes doesn’t work properly and a node having SElinux enabled won’t be able to join the cluster.
So when a node doesn’t join the cluster where it should, my first reflex is to have a look at audit.log. But recently I faced another problem: the node joined the cluster but SST failed (whatever which method was used, discarding skip).
I checked SElinux and it was of course disabled, then I add some debug information in the SST script but it seemed that the script was never launched. And this time the culprit is called : AppArmor !
Percona doesn’t provide any AppArmor profile for PXC, but it seems that on this server (Ubuntu TLS), a previous version of MySQL was [Read more...]