CockroachDB has a rather nice admin interface that monitors the health of the cluster.

https://www.cockroachlabs.com/docs/explore-the-admin-ui.html

There's also a lot of rpc end points used for the admin UI that can be queried to get more fine grain info. However, they're primarily for internal use and might change in the future.

https://github.com/cockroachdb/cockroach/blob/master/pkg/ser...

https://github.com/cockroachdb/cockroach/blob/master/pkg/ser...