helm: support PriorityClassName on gateway-proxy

[sam-heilbron]

Description

Ensure that gateway-proxy deployments respect the gatewayProxy.NAME.kind.deployment.priorityClassName field. This API allows you to set the PriorityClassName for gateway-proxy Pods. This is already supported on all other Gloo deployments.

Context

Priority and Preemption

https://kubernetes.io/docs/concepts/scheduling-eviction/pod-priority-preemption/

This is an important Kubernetes feature, that is especially relevant for Pods (like the data plane) that customers want to assign high priorities to.

Helm API

We have a PodSpec API, which was available under kind.deployment, but was not being used. I added a comment to clarify how this is confusing to developers.

Solution

I re-used an existing Helm field in our PodSpec.

This allows us to expose the relevant APIs that caused users to rely on the kubeResourceOverride. When using that override, users hit #8025.

Interesting decisions

Testing steps

• I added a unit test to verify that this configures the field, as expected
• All Helm unit tests pass locally:

TEST_PKG=install/test/... make test

• I opened an EE PR to share a dev build with @AlfredoFausto (https://github.com/solo-io/solo-projects/pull/6753)

Notes for reviewers

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

[solo-changelog-bot]

Issues linked to changelog:
#8677
#9010

[solo-changelog-bot]

Issues linked to changelog:
#8677
#9010
#9823

[solo-changelog-bot]

Issues linked to changelog:
#8677
#9010
#9823
#9731

[github-actions]

Visit the preview URL for this PR (updated for commit 7276992):

https://gloo-edge--pr9902-sh-helm-priority-cla-dwmllarw.web.app

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