Make the webhook port number configurable

[sel]

Changes

Previously the webhook listened on a fixed port, 8443, which is
likely to clash with other services when the webhook is run on the
host network in Kubernetes, which is required when using some CNI
implementations, notably Calico on EKS [1].

Enable configuration of the webhook listen port through the environment
variable WEBHOOK_PORT by using the existing API from the KNative SDK.

[1] https://projectcalico.docs.tigera.io/getting-started/kubernetes/managed-public-cloud/eks#install-eks-with-calico-networking

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has Docs included if any changes are user facing
• Has Tests included if any functionality added or changed
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  functionality, content, code)
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Release Notes

The port on which the webhook server listens may be configured via the WEBHOOK_PORT environment variable.

[tekton-robot]

Hi @sel. Thanks for your PR.

I'm waiting for a tektoncd member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[sel]

/kind features

[tekton-robot]

@sel: The label(s) kind/features cannot be applied, because the repository doesn't have them.

In response to this:

/kind features

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[sel]

/kind feature

[XinruZhang]

Thanks for the PR! You may also want to add an ENV variable here:

pipeline/config/webhook.yaml

Lines 88 to 109 in db4c05c

	env:
	- name: SYSTEM_NAMESPACE
	valueFrom:
	fieldRef:
	fieldPath: metadata.namespace
	# If you are changing these names, you will also need to update
	# the webhook's Role in 200-role.yaml to include the new
	# values in the "configmaps" "get" rule.
	- name: CONFIG_LOGGING_NAME
	value: config-logging
	- name: CONFIG_OBSERVABILITY_NAME
	value: config-observability
	- name: CONFIG_LEADERELECTION_NAME
	value: config-leader-election
	- name: CONFIG_FEATURE_FLAGS_NAME
	value: feature-flags
	- name: WEBHOOK_SERVICE_NAME
	value: tekton-pipelines-webhook
	- name: WEBHOOK_SECRET_NAME
	value: webhook-certs
	- name: METRICS_DOMAIN
	value: tekton.dev/pipeline

And add comments here telling users to keep this the same as the ENV variable WEBHOOK_PORT

pipeline/config/webhook.yaml

Line 127 in db4c05c

containerPort: 8443

As well as this line, can simply replace 8443 with https-webhook (the name of the container port):

pipeline/config/webhook.yaml

Line 174 in db4c05c

targetPort: 8443

[XinruZhang]

Thanks Steve! Do you mind merging the two commits into one? BTW I don't have the permission to approve the PR request yet, so need to assign the previous reviewers back :)

/assign @dibyom
/assign @pritidesai

[sel]

Thank-you for your review, @XinruZhang!

I have squashed the commits.

And apologies for removing the other reviewers, I think that happened when I hit the "Request re-review" button here on GitHub.

[XinruZhang]

/assign

LGTM from a reviewer that has no LGTM permission XD

[dibyom]

/ok-to-test

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom, vdemeester

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[dibyom]

/lgtm