Is this a BUG REPORT or FEATURE REQUEST?: FEATURE REQUEST

Uncomment only one, leave it on its own line:

/kind bug

/kind feature

Currently for querying all children resources, a k8s user needs to define custom labelling. The problem comes to transferring knowledge of this labelling. For example, etcd operator might add labels etcd_cluster=<cluster-name> to etcd pods, services. But consumers of etcd operator needs to understand etcd operator's labelling convention. This has caused two problems:

• Even if detailed docs is provided, users are reluctant to follow it. They want to define their own labelling in order to query children resources. This causes inconsistency. And querying children resources is very common and everyone does (duplicates) it.
• It couples development team and consumer. Whatever labels has been created, modified, it will affect the consumers.

It's a better way to handle this if k8s can provide feature to query children resources:

• It is a very common use.
• k8s itself needs it as well, e.g. GC
• This is more efficient and simple if reserve index is built inside APIServer.