$ kubectl run nginx --image=nginx --replicas=3 --port=80 --expose
# 验证测试nginx服务
$ kubectl get pod -o wide 
NAME                     READY     STATUS    RESTARTS   AGE       IP               NODE
nginx-7587c6fdb6-p2fpz   1/1       Running   0          55m       172.20.125.2     10.0.96.7
nginx-7587c6fdb6-pbw7c   1/1       Running   0          55m       172.20.124.2     10.0.96.6
nginx-7587c6fdb6-v48db   1/1       Running   0          55m       172.20.121.195   10.0.96.4
$ kubectl get svc nginx
NAME      TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE
nginx     ClusterIP   10.68.7.183   <none>        80/TCP    1h

$ kubectl run busy1 --rm -it --image=busybox /bin/sh
If you don't see a command prompt, try pressing enter.
/ # wget --spider --timeout=1 nginx
Connecting to nginx (10.68.7.183:80)

$ cat > default-deny.yaml << EOF
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny
spec:
  podSelector: {}
  policyTypes:
  - Ingress
EOF
$ kubectl create -f default-deny.yaml
networkpolicy "default-deny" created
$ kubectl run busy1 --rm -it --image=busybox /bin/sh
If you don't see a command prompt, try pressing enter.
/ # wget --spider --timeout=1 nginx
Connecting to nginx (10.68.7.183:80)
wget: download timed out

$ cat > nginx-policy.yaml << EOF
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: access-nginx
spec:
  podSelector:
    matchLabels:
      run: nginx
  ingress:
  - from:
    - podSelector:
        matchLabels:
          access: "true"
EOF
$ kubectl create -f nginx-policy.yaml
networkpolicy "access-nginx" created

# 不带access=true标签的Pod还是无法访问nginx服务
$ kubectl run busy1 --rm -it --image=busybox /bin/sh
If you don't see a command prompt, try pressing enter.
/ # wget --spider --timeout=1 nginx
Connecting to nginx (10.68.7.183:80)
wget: download timed out

# 而带有access=true标签的Pod可以访问nginx服务
$ kubectl run busy2 --rm -it --labels="access=true" --image=busybox /bin/sh
If you don't see a command prompt, try pressing enter.
/ # wget --spider --timeout=1 nginx
Connecting to nginx (10.68.7.183:80)

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: test-network-policy
  namespace: default
spec:
  podSelector:
    matchLabels:
      role: db
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - ipBlock:
        cidr: 172.17.0.0/16
        except:
        - 172.17.1.0/24
    - namespaceSelector:
        matchLabels:
          project: myproject
    - podSelector:
        matchLabels:
          role: frontend
    ports:
    - protocol: TCP
      port: 6379
  egress:
  - to:
    - ipBlock:
        cidr: 10.0.0.0/24
    ports:
    - protocol: TCP
      port: 5978

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  namespace: your-ns
  name: deny-other-namespaces
spec:
  podSelector:
    matchLabels:
  ingress:
  - from:
    - podSelector: {}

# 创建示例应用待暴露服务
$ kubectl run web --image=nginx --labels=app=web --port 80 --expose

# 创建网络策略
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: web-allow-external
spec:
  podSelector:
    matchLabels:
      app: web
  ingress:
  - from: []
    ports:
    - protocol: TCP
      port: 80