PDBs created by operator don't seem fonctional

[SebPlv]

Hi,

Here's what I see in the PDBs created for the kafka controllers and brokers by the operator :

Name:           servicemsg-kafka
Namespace:      servicemsg
Min available:  8
Selector:       strimzi.io/cluster=servicemsg,strimzi.io/kind=Kafka,strimzi.io/name=servicemsg-kafka
Status:
    Allowed disruptions:  1
    Current:              9
    Desired:              8
    Total:                9
Events:
  Type     Reason                           Age                 From               Message
  ----     ------                           ----                ----               -------
  Warning  CalculateExpectedPodCountFailed  34m (x23 over 46m)  controllermanager  Failed to calculate the number of expected pods: strimzipodsets.core.strimzi.io does not implement the scale subresource

And we always have issues during node drain, the strimzi pods are not deleted because of this error.

I haven't found anything about this message in the documentation nor among the issues, so I guess we are missing something... Any help would be appreciated !

[scholzj]

The StrimziPodSet resource by its design cannot implement the scale subresource. So the warning is technically correct in saying that it does not implement the scale subresource. But I never saw any issues related to that and you haven't really explained what the issue is supposed to be either.

[scholzj]

In general, leaving the draining to Kubernetes does ot guarantee high availability of your Kafka cluster because that is not really a Pod state (ready or not ready) but a cluster state (does the cluster have enough other online replicas on other nodes etc.). So the Drain Cleaner takes care of this by capturing the eviction requests and leaving it to the operator to roll the pods safely. There are chapters in the docs about the Drain Cleaner that cover more details installation, etc.

[SebPlv]

It makes totally sense.
We'll plan to implement it.

Thanks again

[scholzj]

Out of curiosity ... can you share the Strimzi version you use and the environment you use (Kube version, distribution, etc.)?

[SebPlv]

Sure, we are using Strimzi v0.48.0 on k8s v1.31 (rke2 and Tanzu onprem distibutions)

[scholzj]

Ok, thanks for the info. I do not have either of those environments to test it, I'm afraid. But it is good to know for a reference.