Kubernetes Networking & Service Discovery

In Kubernetes, what is the main principle of cluster networking?

Which Kubernetes Service type exposes an application externally with a cloud provider’s load balancer?

What does this YAML define?

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  type: NodePort
  selector:
    app: myapp
  ports:
    - port: 80
      targetPort: 8080
      nodePort: 30007

How do pods discover other services in Kubernetes?

What is the main role of an Ingress in Kubernetes?

What is the function of this YAML snippet?

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
spec:
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

What is the purpose of a NetworkPolicy in Kubernetes?

What does this NetworkPolicy allow?

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-frontend
spec:
  podSelector:
    matchLabels:
      role: backend
  ingress:
  - from:
    - podSelector:
        matchLabels:
          role: frontend

What is a headless service in Kubernetes?

In a Service YAML, what does targetPort define?