PodDisruptionBudget and /eviction subresource

[davidopp]

Enhancement Description

• One-line enhancement description (can be used as a release note): PodDisruptionBudget is an API object that specifies the minimum number or percentage of replicas of a collection that must be up at a time, and/or the maximum eviction rate across the collection. Components that wish to eviction a pod subject to disruption budget use the /eviction subresource on pod; unlike a regular pod deletion, this operation may be rejected by the API server if the eviction would cause a disruption budget to be violated.
• Kubernetes Enhancement Proposal: https://github.com/kubernetes/enhancements/tree/master/keps/sig-apps/85-Graduate-PDB-to-Stable
• Primary contact (assignee): @mortent
• Responsible SIGs: sig-apps
• Enhancement target (which target equals to which milestone):
  • Alpha release target (x.y): 1.4
  • Beta release target (x.y): 1.5
  • Stable release target (x.y): 1.21 (PDB), 1.22 (Eviction)
• Alpha
  • KEP (k/enhancements) update PR(s):
  • Code (k/k) update PR(s):
  • Docs (k/website) update PR(s):
• Beta
  • KEP (k/enhancements) update PR(s):
  • Code (k/k) update PR(s):
  • Docs (k/website) update(s):
• Stable
  • KEP (k/enhancements) update PR(s): Update PDB KEP with latest status #2591
  • Code (k/k) update PR(s): Promote PodDisruptionBudget to policy/v1 kubernetes#99290
  • Docs (k/website) update(s): Promote Pod Disruption Budgets to GA website#27053, Update eviction example to use policy/v1 website#27810

[davidopp]

cc/ @mml

[jaredbhatti]

@davidopp Are docs required for this feature?

[davidopp]

Yes, @mml is starting to work on it.

[jaredbhatti]

@mml Another ping on docs. Any PRs you can point me to?

[davidopp]

Planning to move this to Beta in 1.5, see kubernetes/kubernetes#25321

[erictune]

Please consider kubernetes/kubernetes#34776 before beta, as addressing it might be a breaking API change (makes a required field optional).

[davidopp]

Is it really not allowed to add a mutually exclusive field once something is already in Beta? I don't understand why that would be the case (I may be missing something though). I thought the "backward compatibility" requirement for Beta just meant that an object from the old API version has to be usable in the new binary version. It seems that would be the case, since the new binary version understands both fields.