populate cloud labels with cluster autoscaler tags

[sethpollack]

No description provided.

[justinsb]

Happy to see this - thank you for writing it..

First though, I'm not sure this is the right place for the code. This will add those cloud labels explicitly to the instancegroup (which is OKish), but I think it will only do so on initial creation - if you change the labels later, it won't add them.

Also, we merge labels from the cluster. I think it's probably simpler to just add these labels silently as part of AWS ASG creation. Check out this line:

kops/pkg/model/awsmodel/autoscalinggroup.go

Line 198 in 2222111

tags, err := b.CloudTagsForInstanceGroup(ig)

I suspect that is the right location for the logic.

I'm not sure what we do if the label or taint can't fit / isn't valid for the AWS tag. Hopefully people choose reasonable labels & taints, but we don't want to break people's clusters that chose difficult names. I haven't checked on the length limits / which characters are valid though....

Not sure if these labels are expected to propagate to the instances or not. Currently all our tags do propagate (https://github.com/kubernetes/kops/blob/master/upup/pkg/fi/cloudup/awstasks/autoscalinggroup.go#L170). I suspect it is harmless, so not going to block this PR for that.

[sethpollack]

Ok, updated

Also

The maximum key length is 127 Unicode characters.
The maximum value length is 255 Unicode characters.

[justinsb]

/lgtm

Thanks @sethpollack

[k8s-github-robot]

/test all [submit-queue is verifying that this PR is safe to merge]

[k8s-github-robot]

Automatic merge from submit-queue