Label nodes in a single zone IG with AZ ID

[backjo]

Is this a BUG REPORT or FEATURE REQUEST?:
Feature Request
What happened:
As a cluster operator, it would be useful to have Instance Manager label nodes - and annotate the IG - in a single AZ IG with the Availability Zone ID (i.e. usw2-az2, NOT us-west-2a). This could be useful for operators that run clusters across multiple accounts, as it would allow them to write automation against the AZ ID - which would be useful in cases where a single AZ is having an issue in an AWS region.

[eytan-avisror]

Technically the subnet selection in the CR corresponds with AZs, so are you suggesting to resolve the AZs for those subnets and maintain an annotation such as instancemgr.keikoproj.io/availability-zones: usw2-az1,usw2-az2,usw2-az3 ?

I think the use-case for annotating nodes is understandable, but maybe the IG metadata for AZ should be in the status field since we don't want people changing it

[backjo]

@eytan-avisror I think it's more desirable to keep the metadata as a label on the IG - so that folks that may want to use it can target it with a selector. If we implement it correctly, I'd expect the controller to just reset the label on reconcile if someone changes it.