Use Gatekeeper mutating webhooks to auto-assign Pods from a namespace to a specific node pool

assign-kube-system-node-selector.yaml

apiVersion: mutations.gatekeeper.sh/v1
kind: Assign
metadata:
  name: kube-system-node-selector
spec:
  applyTo:
  - groups: [""]
    kinds: ["Pod"]
    versions: ["v1"]
  match:
    scope: "Namespaced"
    namespaces: ["a-team"]
  location: 'spec.nodeSelector.team'
  parameters:
    assign:
      value: "a-team"