Is your feature request related to a problem? Please describe.

ha_max_clusters is a runtime config which configures maximum number of clusters/replica groups that HA tracker will keep track of for single user.

As a user, there is no visibility to check number of replica groups each user has as it is not exposed as a metric so it is hard to configure ha_max_clusters. We have to rely on information from users about how many clusters they have.

Describe the solution you'd like

https://github.com/cortexproject/cortex/blob/master/pkg/ha/ha_tracker.go#L411

This is where the ha_max_clusters limit getting applied. We can add a goroutine to periodically update tenant HA replica groups to metrics.