Router can migrate to use LivenessProbe.TerminationGracePeriodSeconds

Description of problem

In OpenShift 4.7.0 and 4.6.20, cluster-ingress-operator started using the OpenShift-specific unsupported.do-not-use.openshift.io/override-liveness-grace-period-seconds annotation for router pods as a short-term measure to configure the liveness probe's grace period in order to fix OCPBUGSM-20760 (BZ#1899941). This annotation is implemented by a carry patch in openshift/kubernetes.

Since then, upstream Kubernetes has added a terminationGracePeriodSeconds API field to configure the liveness probe using a formal API (upstream doc reference). Using this API field will allow for the carry patch to be removed from openshift/kubernetes.

Example:

spec:
  terminationGracePeriodSeconds: 3600  # pod-level
  containers:
  - name: test
    image: ...

    ports:
    - name: liveness-port
      containerPort: 8080
      hostPort: 8080

    livenessProbe:
      httpGet:
        path: /healthz
        port: liveness-port
      failureThreshold: 1
      periodSeconds: 60
      # Override pod-level terminationGracePeriodSeconds #
      terminationGracePeriodSeconds: 10 

Version-Release number of selected component (if applicable)

OpenShift 4.13.

How reproducible

Always.

Steps to Reproduce

1. Check the annotation and API field on a running cluster: oc -n openshift-ingress get pods -Lingresscontroller.operator.openshift.io/deployment-ingresscontroller=default -o 'custom-columns=NAME:.medadata.name,ANNOTATION:.metadata.annotations.unsupported\.do-not-use\.openshift\.io\/override-liveness-grace-period-seconds,SPEC:.spec.containers[0].livenessProbe.terminationGracePeriodSeconds'

Actual results

The annotation is set, and the spec field is not:

% oc -n openshift-ingress get pods -Lingresscontroller.operator.openshift.io/deployment-ingresscontroller=default -o 'custom-columns=NAME:.metadata.name,ANNOTATION:.metadata.annotations.unsupported\.do-not-use\.openshift\.io\/override-liveness-grace-period-seconds,SPEC:.spec.containers[0].livenessProbe.terminationGracePeriodSeconds'
NAME                              ANNOTATION   SPEC
router-default-677f956f8b-d5lqz   10           <none>
router-default-677f956f8b-hntbb   10           <none>

Expected results

The annotation is not set, and the spec field is:

% oc -n openshift-ingress get pods -Lingresscontroller.operator.openshift.io/deployment-ingresscontroller=default -o 'custom-columns=NAME:.metadata.name,ANNOTATION:.metadata.annotations.unsupported\.do-not-use\.openshift\.io\/override-liveness-grace-period-seconds,SPEC:.spec.containers[0].livenessProbe.terminationGracePeriodSeconds'
NAME                              ANNOTATION   SPEC
router-default-677f956f8b-d5lqz   <none>       10
router-default-677f956f8b-hntbb   <none>       10