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I have a Kubernetes cluster on AWS set up with KubeAWS. We're using some sensitive third-party integrations that require white-listed IP addresses in their firewall.

Now, what I've done is that I've registered the IP addresses of the nodes with the external services and added a node label (whitelisted-ip=true) to those nodes. Services that need to contact those third party providers then have this set as a nodeSelector. So far so good.

Now, the problem I run into is when the cluster starts scaling, in particular, when it's scaling down. The cluster doesn't seem to care which node it removes, so If I have two nodes in one availability zone, it might as well remove the one which has the white-listed IP, which is then released.

Can I instruct my cluster to, when scaling down, first remove nodes that don't have the node label whitelisted-ip=true?

Thanks!

Helge Talvik Söderström
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1 Answers1

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I see that I never shared the answer to this question.

As per this post, there's an annotation to solve this problem:

$ kubectl annotate node <nodename> cluster-autoscaler.kubernetes.io/scale-down-disabled=true

This will prevent Kubernetes from scaling down the node in question.

Helge Talvik Söderström
  • 161
  • 6