Kops: FR: Single node cluster (one master, and no nodes)

[jedateach]

It is not clear how to deploy a single node cluster, with a single, schedule-able master. This will be useful for developers getting started to keep costs down, or perhaps could help in testing scenarios. Minikube works for local dev, but there isn't a simple equivalent solution for live servers.

Issue #152 suggests that nodes size could be set to 0: https://github.com/kubernetes/kops/issues/152

However, I have tried this from both in the cli:

kops create cluster --node-count=0 ${CLUSTER_NAME}

That didn't affect the maxSize and minSize values in the nodes ig file.

Values can be changed by editing the nodes instance group config:

kops edit ig nodes --name=${CLUSTER_NAME}

After editing however, the resulting cluster config output yaml appears correct, but running kops update cluster ${CLUSTER_NAME} will still include a single instance launch configuration for the nodes instance group.

[jedateach]

Should this work already, and we need some documentation, or is this a genuine feature request?

[jedateach]

I'm closing this, as I appear to have fixed the issue. Autoscaling group for nodes set min and max values to 0.

[vinayagg]

Hi Jeremy,

Can you (or anyone) give little details how to do this? My questions are:

1. does --node-count=0 automatically works? I tried it but the resulting IG has node count=2.
   Do I need to manually edit node ig config with node count = 0 before starting cluster?

1. With this config, is master automatically configured to schedule pods? AFAIK, by default pods are not scheduled on master nodes.

[jedateach]

Hi @vinayagg,

1. No I couldn't get that to work myself. I had to do the manual edit.
2. Yes, I had to remove the noschedule taint from the master - which is conveniently provided by the uncordon command:

kubectl uncordon $MASTER_NODE_NAME

[jedateach]

Because the solution to this issue is really a workaround what kops can't do, I'll reopen the issue.

[vinayagg]

I had opened another issue, they are now duplicate
https://github.com/kubernetes/kops/issues/3073

[jedateach]

Ok, great thanks.