Exception request: configurable grace period for probes

[Elana Hashman]

• Enhancement name: Add configurable grace period to probes
  
• Enhancement status (alpha/beta/stable): Alpha
  
• SIG: Node
  
• k/enhancements repo issue #: https://github.com/kubernetes/enhancements/issues/2238
• PR #’s: https://github.com/kubernetes/kubernetes/pull/99375
• Additional time needed (in days): 1-2 (work is complete, just need time to receive final approval)
  
• Reason this enhancement is critical for this milestone: bugfix for a longstanding accidental coupling of pod spec values that requires an API change to fix, meaning it needs 3 releases to graduate.
  
• Risks from adding code late: Low risk. Change itself is very targeted within the kubelet and is gated with a feature flag for alpha. It is tested e2e.
  
• Risks from cutting enhancement: Delaying this fix means that it will take an extra 3-4 months to graduate and benefit all users.

Note that PR had approval comments and LGTM before deadline, but did not have an "approved" label as the API approval comment lacked an /approve.

[Nabarun Pal]

Hi Elana,

Considering that the API change has already been reviewed (in the time
between the request for an exception and writing this response) and
the risk is deemed to be minimal and gated (ref:
https://github.com/kubernetes/kubernetes/pull/99375#issuecomment-796228946),
we are APPROVING this exception request.

Best,
Nabarun Pal // Kubernetes 1.21 Release Lead