Extend ReplicaSet or make a "CRD Set" about kubernetes

[k8s-ci-robot]

This issue is currently awaiting triage.

If a SIG or subproject determines this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[Irvingwangjr]

Like right now replicaSet simply creates "replicas" of child objects and deletes them when we scale down the replicaSet, that's what I need.

But for further scenarios, like replicaSet will check Pod's Status whether in Pending State, maybe can be switched to check the condition (like asking the workload to implement the condition as a subResource? like the /Scale) and define some will-known-condition like annotation of pod-deletion-cost. so it can be compatible with CRDs not just pods.

I think the Probe set a great pattern, it allows users to set a few common ways to detect the status of real programs, And in the world of Kubernetes, labels/annotations/conditions are the most common ways that CRDs communicate with each other.
so if today I hope to know whether a CR is 'healthy' or not, I should be able to know it through label/annotation/condition. From this perspective, I think it is possible to build a Pod-Less ReplicaSet or ReplicaSet-less Deployment.

[Aaina26]

/sig apps