add pod anti affinity rules to activator component (#15259)

Co-authored-by: Izabela Gomes <[email protected]>

config/core/deployments/activator.yaml

@@ -35,6 +35,17 @@ spec:
  app.kubernetes.io/name: knative-serving
  app.kubernetes.io/version: devel
  spec:
+ # To avoid node becoming SPOF, spread our replicas to different nodes.
+ affinity:
+ podAntiAffinity:
+ preferredDuringSchedulingIgnoredDuringExecution:
+ - podAffinityTerm:
+ labelSelector:
+ matchLabels:
+ app: activator
+ topologyKey: kubernetes.io/hostname
+ weight: 100
+
  serviceAccountName: activator
  containers:
  - name: activator