Expose cluster autoscaler "--balancing-ignore-label" flag through ClusterAutoscaler CRD

User Story

As an OpenShift operator, i would like to be able to add labels to my MachineSets and nodes which contain unique values, while also using the cluster autoscaler's ability to balance similar node groups. Being able to specify additional labels through the ClusterAutoscaler CRD would allow me to do that.

Background

Something that has arisen during the investigation of https://bugzilla.redhat.com/show_bug.cgi?id=2001027 is the notion that each CSI driver could create its own zone topology labels, and that they do not have to be consistent with the well known kubernetes label.

It is possible, although not entirely confirmed, that a CSI driver might add these labels even when not in use (although running in the cluster).

Additionally, users may need the option to specify more labels to ignore (as illustrated in the discussion of the bug).

Steps

• Add a new API field for the labels to ignore
• it should be a list
• write some unit tests
• update our balance node e2e test

Stakeholders

• cloud team, qe

Definition of Done

• field and functionality added

• Docs

• product docs will need an update

• Testing

• unit and e2e