Unable to opt-out of aggressive probing

[dprotaso]

/area API

What version of Knative?

All version

Expected Behavior

Setting ReadinessProbe.PeriodSeconds >= 1 should default into K8s style probing.

Actual Behavior

The queue proxy exec probe has a retry tight loop that defaults to the aggressive interval and not the user's defined PeriodSeconds

Steps to Reproduce the Problem

Create an app that fails probing a few times (~3) with the following config

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: default-probe
  namespace: default
spec:
  template:
    spec:
      containers:
      - image: ${RUN_IMAGE}
        readinessProbe:
          httpGet:
            path: /
          periodSeconds: 1
          timeoutSeconds: 1
          failureThreshold: 1

Technically the app should start after ~3s. Instead it behaves the same as periodSeconds is set to zero.

[dprotaso]

/area API

[dprotaso]

/assign @dprotaso

[dprotaso]

/close

The intent of this issue was to fix the queue proxy probing timing. I've come to realize the activator does it's own aggressive probing (every ~200ms) so it's effectively by-passing the readiness signal to the API server.

I'm going to close this out as a no-fix for now cause I don't think the activator should customize it's probing logic per revision.