scaling down the instance group does not have any effect

[zetaab]

1. What kops version are you running? The command kops version, will display
this information.

master

2. What Kubernetes version are you running? kubectl version will print the
version if a cluster is running or provide the Kubernetes version specified as
a kops flag.

1.11.6

3. What cloud provider are you using?

openstack

4. What commands did you run? What is the simplest way to reproduce this issue?

• scale instancegroup up, for instance kops edit ig --name clustername nodes edit minsize to 5
• run kops update cluster clustername --yes

After this you should be able to see 5 nodes, then downscale

• scale instancegroup down, for instance kops edit ig --name clustername nodes edit minsize to 1
• run kops update cluster clustername --yes

5. What happened after the commands executed?

Machines are not scaled down

6. What did you expect to happen?

I except that if I specify minsize to one and run update cluster, it should remove machines that is not needed.

/sig openstack
/kind bug

[zetaab]

I am thinking that should we check here https://github.com/kubernetes/kops/blob/master/pkg/model/openstackmodel/servergroup.go#L74 how many servers do we have in openstack servergroup? if there are Members more than MinSize it should delete instances? Create new deleteinstance task or how it should work?

[drekle]

#6385 is useful here as you've implemented delete instance. I believe the existing server group task should find the server group, with members which represent the UUID of a server, and can be removed only if they are over MaxSize. I believe and autoscaler should do any logic determining whether or not the instances over MinSize are needed or not, as it has greater visibility about the pods in a cluster.

Ill try to pick this up if we can get the aws pull test to pass.

[drekle]

@zetaab I believe this is resolved?

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[k8s-ci-robot]

@fejta-bot: Closing this issue.

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