Cluster Autoscaler: when the pool size has been scaled down to zero, it will never trigger new scale out.

[delulu]

Which component are you using?: cluster-autoscaler

What version of the component are you using?: Cluster Autoscaler 1.21.1

Component version:

What k8s version are you using (kubectl version)?: 1.21.3

kubectl version Output

$ kubectl version

What environment is this in?: Azure VMSS

What did you expect to happen?: The cluster autoscale will make sure the node size will be no less than minimal node count setting.

What happened instead?:

When the pool size has been scaled down to zero, it will never trigger new scale out.
Cluster Autoscaler doesn’t work as expected to:

1. bring the minimal nodes back
2. trigger nodes scale out when there’re pending pods

How to reproduce it (as minimally and precisely as possible):

Scale down the agent pool to zero node, the you can watch its behavior as shown above.

Anything else we need to know?:

[mmerrill3]

See this: #4739

[delulu]

So could someone confirm that this issue will be fixed in 8f11490 and resolved in cluster-autoscaler v1.22.0 onwards?

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/lifecycle rotten

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/close

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue.

In response to this:

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues and PRs according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

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/close

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