tekton-pipelines-webhook HorizontalPodAutoscaler should be set to minReplicas:2 to prevent disruption when pods are being restarted

Description of problem:

According to Availability, webhook should be made highly available to improve reliability and overall performance. Currently HorizontalPodAutoscaler configures tekton-pipelines-webhook with minReplicas:1 which can cause disruption when the specific pod is being restarted and thus trigger undesired problems for PipelinesRuns.

In order to prevent issues, it's requested to have HorizontalPodAutoscaler for tekton-pipelines-webhook configured with minReplicas:2 by default to achieve fault tolerance. If that is not possible, it should be possible to configure minReplicas in HorizontalPodAutoscaler for tekton-pipelines-webhook so customers can set it to desired value.

Workaround

N/A

Prerequisites (if any, like setup, operators/versions):

Install OpenShift Pipelines (any version) on OpenShift Container Platform 4 and check HorizontalPodAutoscaler for tekton-pipelines-webhook

Steps to Reproduce

Install OpenShift Pipelines (any version) on OpenShift Container Platform 4 and check HorizontalPodAutoscaler for tekton-pipelines-webhook
 

Actual results:

When HorizontalPodAutoscaler for tekton-pipelines-webhook does not trigger scaling of tekton-pipelines-webhook and the associated pod is restarted, errors may occur during PipelinesRuns and thus impact overall customer experience.

Expected results:

As per Availability, webhook should be made highly available by default to prevent disruption when maintenance on the respective pods or infrastructure is being done.

Reproducibility (Always/Intermittent/Only Once):

Always

Acceptance criteria: 

Either have HorizontalPodAutoscaler for tekton-pipelines-webhook configured with minReplicas:2 or allow to configure it, if the customer would like to achieve recommended practice.
 

Definition of Done:

Build Details:

N/A

Additional info (Such as Logs, Screenshots, etc):

$ oc get csv openshift-pipelines-operator-rh.v1.12.2
NAME                                      DISPLAY                       VERSION   REPLACES                                  PHASE
openshift-pipelines-operator-rh.v1.12.2   Red Hat OpenShift Pipelines   1.12.2    openshift-pipelines-operator-rh.v1.12.1   Succeeded

$ oc get hpa tekton-pipelines-webhook -o json | jq '.spec.minReplicas'
1