TIL: a status condition is stale if observedGeneration doesn't match generation

I used to treat Ready=True as current truth. It isn’t — not if the condition was written against an older generation of the resource.

Every time you change a Kubernetes object’s .spec, the API server bumps metadata.generation. Controllers that care about “have I reconciled this spec yet?” stamp the generation they last handled into status — usually as status.observedGeneration on the object, and often again as observedGeneration on individual conditions.

So the check is boring and important:

status:
  observedGeneration: 3
  conditions:
    - type: Ready
      status: "True"
      observedGeneration: 3
      reason: Reconciled
      message: desired state matches

If metadata.generation is 4 and that condition still says observedGeneration: 3, the Ready status is about the previous spec. Treat it as stale until a controller rewrites it for generation 4.

Same idea shows up in custom resources and built-ins that follow the API conventions: generation is the version of the desired state; observedGeneration is how far status has caught up. If they diverge, status is lagging — not lying, just not about this generation.