Add support for runtime classes on Acorn computeclasses

[cloudnautique]

Runtime classes are added as in internal value on Acorn compute class objects. This allows for using things like Kata Containers.

[cjellick]

@cloudnautique can you give a practicall example here? I understand this is related to the kata POC. But can you:

1. show me in yaml what the compute class will look like
2. explain what that translates to at a k8s infra level. Like, where does that runtime class get set?

[cjellick]

You are exporting this function. I don't think it is used outside this package. If that's true, can you unexport (lowercase) it?

[cjellick]

Seems like you were copying the pattern of PriorityClassName. If the same is true for that one, please unexport it as well

[cloudnautique]

@cjellick I added an update to the docs, which shows a project compute class YAML. I think that satisfies the compute class yaml request. Please let me know if it doesn't and I can update the docs some more.

The field is set to the string name of a k8s RuntimeClass, an example YAML for one is:

apiVersion: node.k8s.io/v1
handler: kata-clh
kind: RuntimeClass
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"node.k8s.io/v1","handler":"kata-clh","kind":"RuntimeClass","metadata":{"annotations":{},"name":"kata-clh"},"overhead":{"podFixed":{"cpu":"250m","memory":"130Mi"}},"scheduling":{"nodeSelector":{"katacontainers.io/kata-runtime":"true"}}}
  creationTimestamp: "2023-11-21T17:54:07Z"
  name: kata-clh
  resourceVersion: "20424"
  uid: 85d1fdde-834d-4476-adb9-456b74d8e209
overhead:
  podFixed:
    cpu: 250m
    memory: 130Mi
scheduling:
  nodeSelector:
    katacontainers.io/kata-runtime: "true"

The RuntimeClass is set as a field on a K8s pod spec, when this is specified on the compute class a deployment will have it set like:

apiVersion: apps/v1
kind: Deployment
metadata:
  ...
    spec:
      containers:
       ...
        image: ghcr.io/cloudnautique/acorn-minecraft@sha256:fd92271de53157c76cfed9bc7e7bbef5c60b829e76afd7b50612f5cd8e607de9
        ...
      runtimeClassName: kata-clh
      ...