Currently knative serving release uses the registry: gcr.io/knative-releases and the build path: github.com/knative/serving/cmd. Additionally, the tag is built using a sha sha256:1e40c99ff5977daa2d69873fff604c6d09651af1f9ff15aadf8849b3ee77ab45 instead of a tag number 0.6.0. These fields should be customizable, so it could point to a registry of quay.io/openshift-knative or others.

I think it's reasonable to have reasonable defaults from knative serving, but support modifications by changing KnativeServing CR.

The configuration could look like:

apiVersion: serving.knative.dev/v1alpha1
kind: KnativeServing
metadata:
  name: knative-serving
spec:
  config:
  image:
    registry: "my-registry.io/my-knative-release/path"
    tag: "v0.6.0"