client-to-server-netpol.yaml

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  namespace: server-ns
  name: allow-client-ns
spec:
  podSelector:
    matchLabels: {}
  ingress:
    - from:
        - namespaceSelector:
            matchLabels:
              role: client

client-to-server-samens.yaml

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  namespace: server-ns
  name: same-ns-policy
spec:
  podSelector:
    matchLabels:
      role: server-pod
  ingress:
    - from:
        - podSelector:
            matchLabels:
              run: tmp-shell
      ports:
        - protocol: TCP
          port: 80