service

目录

• ClusterIP
• NodePort
• LoadBalancer
• ExternalName
• session 亲和性

测试用例

kubectl create deploy test-web --image=python -- python -m http.server

depoy.yaml

    	
 
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: test-web
  name: test-web
spec:
  replicas: 1
  selector:
    matchLabels:
      app: test-web
  template:
    metadata:
      labels:
        app: test-web
    spec:
      containers:
      - command:
        - python
        - -m
        - http.server
        image: python
        name: python
    

ClusterIP

只能在集群内部访问服务

类型一：默认类型

kubectl expose deploy test-web --port=80 --protocol=TCP --target-port=8000 --type=ClusterIP

svc.yaml

 
apiVersion: v1
kind: Service
metadata:
  labels:
    app: test-web
  name: test-web
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8000
  selector:
    app: test-web
  type: ClusterIP

类型二：cluserIP=None这种类型常用于statefulset中。当访问此类应用时，svc不做负载均衡而是将域名直接解析为后端的pod

svc.yaml

 
apiVersion: v1
kind: Service
metadata:
  labels:
    app: test-web
  name: test-web
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8000
  selector:
    app: test-web
  clusterIP: None
  type: ClusterIP

类型三： 不带selector指令，常用于访问集群外的服务

svc.yaml

 
apiVersion: v1
kind: Service
metadata:
  name: test-web-noselector
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8000
  type: ClusterIP
---
apiVersion: v1
kind: Endpoints
metadata:
  name: ep-01
subsets:
  - addresses:
       - ip: 10.4.7.1
    ports:
       - port: 8000

NodePort

在ClusterIP的基础上增加了对外访问的端口。既可以在集群内访问又可以在集群外通过nodePort 访问

kubectl expose deploy test-web --port=80 --protocol=TCP --target-port=8000 --type=NodePort

svc.yaml

 
apiVersion: v1
kind: Service
metadata:
  labels:
    app: test-web
  name: test-web
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8000
  selector:
    app: test-web
  type: NodePort

LoadBalancer

ExternalName

session 亲和性

如果要确保每次都将来自特定客户端的连接传递到同一 Pod， 则可以通过将 service.spec.sessionAffinity 设置为 "ClientIP" （默认值是 "None"），来基于客户端的 IP 地址选择会话关联。
你还可以通过适当设置 service.spec.sessionAffinityConfig.clientIP.timeoutSeconds 来设置最大会话停留时间。 （默认值为 10800 秒，即 3 小时）

apiVersion: v1
kind: Service
metadata:
  name: nodeport-type
spec:
  type: ClusterIP
  sessionAffinity: ClientIP
  sessionAffinityConfig:
    clientIP: 10800
  selector:
    app: nginx
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80