Example for network policies with ingress

ing.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: nginx
        resources:
          limits:
            memory: "128Mi"
            cpu: "500m"
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: myapp
spec:
  type: LoadBalancer
  selector:
    app: myapp
  ports:
  - port: 80
    targetPort: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
  labels:
    name: myingress
spec:
  ingressClassName: nginx
  rules:
  - http:
      paths:
      - pathType: Prefix
        path: /myapp(/|$)(.*)
        backend:
          service:
            name: myapp
            port: 
              number: 80
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-ingress-controller-to-myapp
spec:
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app.kubernetes.io/name: ingress-nginx
    - namespaceSelector:
        matchLabels:
          name: ingress-nginx
    ports:
    - port: 80
      protocol: TCP
  - from:
    - podSelector:
        matchLabels:
          app: myapp
    ports:
    - port: 80
      protocol: TCP
  podSelector:
    matchLabels:
        app: myapp
  policyTypes:
  - Ingress