Allow pods to self-identify as being unable to deschedule

[specterops-avongluck]

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

As an infrastructure engineer, it would be nice to be able to have pods communicate to descheduler that they should be skipped for descheduling.

Describe the solution you'd like
As an example, some workloads might be sensitive to getting descheduled. It would be nice to add an optional probe of a user-defined http reset service (think http healthcheck, but more of a "terminationcheck")

"hello pod a, are you busy in a way which should prevent descheduling?"

Example:

• Descheduler termCheck:
  HTTP GET http://service/state
  {"status": "busy"}
• Descheduler: bypass termination

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/lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues.

This bot triages un-triaged issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Mark this issue as fresh with /remove-lifecycle rotten
• Close this issue with /close
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/lifecycle rotten