Dynamic, individual nodeAffinity for each pod in a StatefulSet

Andrey Kuznetsov

4/8/23, 2:23 PM

I have two node pools: NP1 and NP2. I have a StatefulSet with pods using ordinal index to retrieve their own configuration from external configuration source.

On certain conditions, I need to reschedule individual pods to either NP1 or NP2. Actual information about which pod should be run on which node pool is stored in a Consul KV object.

I can write a Kubernetes Operator which subscribes on that object and modifies StatefulSet in a way that it reschedules individual pods to a correct node pool when Consul KV object is updated. My question is how can I define different nodeAffinity for each pod?

I've seen some examples of using topologyKey with podAntiAffinity but in my case the decision which node pool a pod should be scheduled on is based on data completely external from kubernetes cluster.

0 + 0

kubernetes

mdaniel

4/8/23, 4:33 PM

I'm pretty sure only a Mutating Webhook will allow you to do dynamic tricks like that; I think OPA has some concessions toward that use case, but I've thankfully never used it

Mikołaj Głodziak

4/9/23, 12:58 PM

Did you see [this page](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/)?

Score:1

Server

Mikołaj Głodziak

4/15/23, 9:44 AM

As far as I know, you can use mutating webhook as mdaniel has mentioned in the comment:

I'm pretty sure only a Mutating Webhook will allow you to do dynamic tricks like that; I think OPA has some concessions toward that use case.

You can also find here more information about Dynamic Admission Control.

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Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Dynamic, individual nodeAffinity for each pod in a StatefulSet

TH: nodeAffinity แต่ละโหนดแบบไดนามิกสำหรับแต่ละพ็อดใน StatefulSet

RO: NodAffinity dinamică, individuală pentru fiecare pod dintr-un StatefulSet

RU: Динамический, индивидуальный nodeAffinity для каждого модуля в StatefulSet

VI: NodeAffinity động, riêng lẻ cho từng nhóm trong StatefulSet

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