* Implement the K8s lifecycle in webhook.
The webhook never properly implemented the Kubernetes SIGTERM/SIGKILL
lifecycle, and doesn't even really support readiness probes today. This
change enables folks to use a block like this on their webhook container:
```yaml
readinessProbe: &probe
periodSeconds: 1
httpGet:
scheme: HTTPS
port: 8443
httpHeaders:
- name: k-kubelet-probe
value: "webhook"
livenessProbe: *probe
```
With this, the webhook won't report as `Ready` until a probe has succeeded,
and when the SIGTERM is received, we will start failing probes for a grace
period (so our Endpoint drops) before shutting down the webhook's HTTP Server.
This was uncovered by running the webhook across 10 replicas in Serving with
the "Goose" (https://github.com/knative/pkg/pull/1316) enabled for the e2e
tests. The failure mode I saw was conversion webhook requests failing across
random tests.
This also moves the Serving probe-detection function into PKG.
* Increase the log level when we start to fail probes
* Wait for go routines to terminate on all paths.
* Move generic packages from serving to pkg.
I was asked to move this to do some re-use in Eventing.
/cc @chizh
/assign mattmoor @tcnghia
* fix the compile error
Matt Moore
Victor Agababov