Services: ClusterIP, NodePort, LoadBalancer, Ingress


Kubernetes - Services Explained

kubernetes Services


ClusterIP

kubernetes ClusterIP


apiVersion: v1
kind: Service
metadata:
  name: my-internal-service
spec:
  selector:
    app: my-app
  type: ClusterIP
  ports:
  - name: http
    port: 80
    targetPort: 80
    protocol: TCP


NodePort

kubernetes NodePort


Запускаю deployment

$ cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: quarkus-demo-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: quarkus-demo
  template:
    metadata:
      labels:
        app: quarkus-demo
        env: dev
    spec:
      containers:
      - name: quarkus-demo
        image: quay.io/burrsutter/quarkus-demo:1.0.0
        imagePullPolicy: Always
        ports:
        - containerPort: 8080
EOF


$ cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Service
metadata:
  name: nodeport-service
spec:
  selector:
    app: quarkus-demo
  type: NodePort
  ports:
  - name: http
    port: 80
    targetPort: 8080
    protocol: TCP
EOF


$ kubectl get services
NAME               TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
nodeport-service   NodePort   10.106.68.183   <none>        80:32321/TCP   17s


$ IP=$(minikube --profile my-profile ip)
$ echo ${IP}
$ PORT=$(kubectl get service nodeport-service -o jsonpath="{.spec.ports[*].nodePort}")
$ echo ${PORT}
$ while true; do curl $IP:$PORT; sleep .5; done


$ kubectl delete services nodeport-service
$ kubectl delete deployment quarkus-demo-deployment


LoadBalancer

kubernetes LoadBalancer

cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mypython-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mypython
  template:
    metadata:
      labels:
        app: mypython
    spec:
      containers:
      - name: mypython
        image: docker.io/burrsutter/mypython:1.0.0
        ports:
        - containerPort: 8000
EOF


$ cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mygo-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mygo
  template:
    metadata:
      labels:
        app: mygo
    spec:
      containers:
      - name: mygo
        image: quay.io/burrsutter/mygo:1.0.0
        ports:
        - containerPort: 8000
EOF


$ cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mynode-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mynode
  template:
    metadata:
      labels:
        app: mynode
    spec:
      containers:
      - name: mynode
        image: quay.io/burrsutter/mynode:1.0.0
        ports:
        - containerPort: 8000
EOF


$ cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Service
metadata:
  name: loadbalancer-service
  labels:
    app: mystuff
spec:
  ports:
  - name: http
    port: 8000
  selector:
    inservice: mypods
  type: LoadBalancer
EOF


$ kubectl label pod -l app=mypython inservice=mypods
$ kubectl label pod -l app=mynode inservice=mypods
$ kubectl label pod -l app=mygo inservice=mypods


$ kubectl get deployments
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
mygo-deployment       1/1     1            1           117s
mynode-deployment     1/1     1            1           2m5s
mypython-deployment   1/1     1            1           10m


$ IP=$(minikube --profile my-profile ip)
$ echo ${IP}
$ PORT=$(kubectl get service loadbalancer-service -o jsonpath="{.spec.ports[*].nodePort}")
$ echo ${PORT}


$ while true; do curl $IP:$PORT; sleep .5; done
Python Hello on mypython-deployment-6874f84d85-kh4g7
Go Hello on mygo-deployment-6d944c5c69-qx2s6
Node Hello on mynode-deployment-fb5457c5-hmf67 0 
Node Hello on mynode-deployment-fb5457c5-hmf67 1 
Go Hello on mygo-deployment-6d944c5c69-qx2s6
Python Hello on mypython-deployment-6874f84d85-kh4g7
Python Hello on mypython-deployment-6874f84d85-kh4g7
Python Hello on mypython-deployment-6874f84d85-kh4g7
Go Hello on mygo-deployment-6d944c5c69-qx2s6


$ kubectl describe service loadbalancer-service


$ kubectl describe service loadbalancer-service
Name:                     loadbalancer-service
Namespace:                demo
Labels:                   app=mystuff
Annotations:              Selector:  inservice=mypods
Type:                     LoadBalancer
IP:                       10.97.67.253
Port:                     http  8000/TCP
TargetPort:               8000/TCP
NodePort:                 http  30460/TCP
Endpoints:                172.17.0.5:8000,172.17.0.6:8000,172.17.0.7:8000
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>


$ kubectl get pods -o wide
NAME                                   READY   STATUS    RESTARTS   AGE   IP           NODE         NOMINATED NODE   READINESS GATES
mygo-deployment-6d944c5c69-qx2s6       1/1     Running   0          18m   172.17.0.6   my-profile   <none>           <none>
mynode-deployment-fb5457c5-hmf67       1/1     Running   0          12m   172.17.0.7   my-profile   <none>           <none>
mypython-deployment-6874f84d85-kh4g7   1/1     Running   0          27m   172.17.0.5   my-profile   <none>           <none>


Ingress

kubernetes Ingress


apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: my-ingress
spec:
  backend:
    serviceName: other
    servicePort: 8080
  rules:
  - host: foo.mydomain.com
    http:
      paths:
      - backend:
          serviceName: foo
          servicePort: 8080
  - host: mydomain.com
    http:
      paths:
      - path: /bar/*
        backend:
          serviceName: bar
          servicePort: 8080


Скапитализжено:

https://medium.com/google-cloud/kubernetes-nodeport-vs-loadbalancer-vs-ingress-when-should-i-use-what-922f010849e0