Percona XtraDB operator with single node detects itself as peer

MySQL & MariaDB Percona Operator for MySQL
1

Hello,

I’m looking into the Percona XtraDB k8s Operator bootstrap behavior when running a single node. When booting a single node, it immediately goes into ‘crash mode’.

In theory, a first time single node should not setup replication, and should bootstrap, correct?

In the pxc node entrypoint, this section always runs, and the node detects itself as a peer, which switches on replication. This sets CLUSTER_JOIN, which instructs the node not to bootstrap here.

Perhaps I’m misunderstanding something. Thanks.

2

Hi Joshua,

The Percona Operator for MySQL based on Percona XtraDB Cluster does not support single node mode.

I think you need to use Percona Operator for MySQL based on Percona Server for MySQL.

I hope this helps.

Pep

3

Hmm, if it doesn’t support single nodes, why is that an option in Everest, which uses the XtraDB operator?

Also, what I’ve noticed in testing is that even with multi-node setups, this happens, so the first member of the StatefulSet never initializes. Surely this is a problem with my particular environment, but I haven’t figured out why yet.

4

@Joshua_Sierles I want to correct @Pep_Pla a bit. PXC supports one node. We even have cr-minimal.yaml as an example to deploy a single node.

And we have lots of use cases where users deploy PXC with a single node for their dev/test environments (as it is obviously not recommended to run a single node in production).

As for the issue you are facing - it needs deeper investigation. It does not happen for me in minikube or GKE (checked just now) + we have a test for this use case. Can you attach the operator logs?

1 Like
5

It’s true; I typed too fast. Although you can run the PXC operator with one node, it is considered unsafe.

That’s why a CR option allows you to run in unsafe mode.

Check for allowUnsafeConfigurations in your cr file. It should be true. If it is false and the single cluster-pxc pod is killed, it does not restart properly.

I hope this helps.

6

Thanks. The issue must be with my k8s environment. I’ll post logs later. Meanwhile, I was able to get the newer MySQL operator working with a single node.