should modify kubeadm config rather than edit the kube-scheduler static manifest

[cbf123]

The existing setup instructions modify the already-existing kube-scheduler static manifest file but don't edit the kubeadm configmap. If someone updates the kubeadm configmap and regenerates the static manifest files (for kube-apiserver, kube-scheduler, etc.) then I think it'll overwrite the changes to the kube-scheduler static manifest file.

Wouldn't it make more sense to edit the kube-scheduler section of the kubeadm configmap and regenerate the static manifest files with "kubeadm init phase control-plane"? That way anyone else making changes won't end up accidentally overwriting the changes.

[madalazar]

Hi!

As you said, the kube-scheduler changes made through our configuration script do not seem to be resilient to kubeadm updates (kubeadm upgrade diff). I'll take a look at the required changes and your proposal. I will also add more info to the issue as things progress.

Thanks for bringing this to our attention!

[madalazar]

Hi! Just wanted to get back to you with some updates. For the time-being, we decided to pause the work on this issue. This is mostly due to not being able to migrate all kube-scheduler manifest properties required by TAS (volumes, config, dnsPolicy) into kube-admin. More specifically, I wasn't able to set the required dnsPolicy property value via kubeadm. As far as I've seen , the property does not exist the ClusterConfiguration object schema and there are no plans to add it (https://github.com/kubernetes/kubernetes/pull/79379/files).

There is a possibility that it can be added via kustomize (https://github.com/kubernetes/kubeadm/issues/1379, https://github.com/kubernetes/enhancements/issues/1177) but I wasn't able to find an example for the property that is needed. Due to time constraints we're not able to explore this avenue further - for now.

We will keep you posted if anything changes.

Thank you for your suggestion!

[eero-t]

Due to time constraints we're not able to explore this avenue further - for now.

Any updates on this?

[madalazar]

Hi, maybe just a small one. While trying to solve this problem I got stuck as I was not able to add the "dnsPolicy" property via kubeadm (the property/parent property was not open for edit or something along those lines). In PR#108 it seems that the property is being added via a Kubeadm patch. Because of this, I created an item into our backlog to look at and try patchind the Kubeadm config file again. It's possible I missed something the first time I looked at it.

I'm going to work tomorrow/Monday and what work we can pick-up in March and then what are the priorities for next quarter. Expect a reply by end of next week with some estimated dates.

Thank you!