2. Services 与 Load Balancing

2.1 Services

2.1.1 Services常用命令

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# 查看Services
kubectl get services

# 创建ClusterIP
kubectl expose deployment <NAME> --type=ClusterIP --target-port=<PORT> --port=<PORT>

# 创建NodePort
kubectl expose deployment <NAME> --type=NodePort --target-port=<PORT> --port=<PORT>

# 创建ExternalName
kubectl create service externalname <NAME> --external-name=www.baidu.com

# 创建Headless Service
kubectl expose deployment <NAME> --type=ClusterIP --cluster-ip=None

# 创建ExternalIP
kubectl expose deployment <NAME> --type=ClusterIP --external-ip=<IP_ADDRESS>

# 删除Service
kubectl delete services <NAME>

2.1.2 ClusterIP类型

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ClusterIP用户实现Kubernetes集群中内部服务的访问

# 编写Yaml
apiVersion: v1
kind: Service
metadata:
  name: clusterip-service
spec:
  type: ClusterIP
  selector:
    app: pod-nginx
  ports:
    - port: 80
      targetPort: 80

2.1.3 NodePort类型

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NodePort用户实现Kubernetes集群内部服务的对外暴露

# 编写Yaml
apiVersion: v1
kind: Service
metadata:
  name: clusterip-service
spec:
  type: NodePort
  selector:
    app: pod-nginx
  ports:
    - port: 80
      targetPort: 80
#      nodePort: 30696

2.1.4 ExternalName类型

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ExternalName用户实现Kubernetes集群中的应用可以通过Service访问集群外地的域名服务

# 编写yaml
apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: ExternalName
  externalName: www.baidu.com

2.1.5 ExternalIP方式

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ExternalIP用户于实现Kubernetes集群内部服务的对外暴露

# 编写Yaml
apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: ClusterIP
  selector:
    app: pod-nginx
  ports:
    - name: http
      protocol: TCP
      port: 18080
      targetPort: 80
  externalIPs:
    - 172.17.210.201
    - 172.17.210.202

2.1.6 Headless Services

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Headless Service用于满足不需要负载均衡或者Service IP的服务

# 编写yaml
apiVersion: v1
kind: Service
metadata:
  name: headless-service
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: statefulset-nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: statefulset-nginx
  serviceName: "headless-service"
  replicas: 3
  template:
    metadata:
      labels:
        app: statefulset-nginx
    spec:
      terminationGracePeriodSeconds: 10
      containers:
      - name: nginx
        image: nginx
        imagePullPolicy: IfNotPresent

2.1.7 External_IP_Port方式

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External_IP_Port用于实现Kubernetes集群中的应用可以通过Service访问集群外部的IP:Port服务

# 编写Service Yaml文件
apiVersion: v1
kind: Service
metadata:
  name: external-ip-port
spec:
  clusterIP: None
  type: ClusterIP
  ports:
    - port: 3306
      targetPort: 3306

# 编写Endpoints Yaml文件
apiVersion: v1
kind: Endpoints
metadata:
  name: external-ip-port
subsets:
- addresses:
  - ip: 192.168.1.1
  ports:
  - port: 3306
    protocol: TCP

2.1.8 会话保持

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# 编写Yaml文件
apiVersion: v1
kind: Service
metadata:
  name: clusterip-service
spec:
  sessionAffinity: ClientIP
    clientIP:
      timeoutSeconds: 10800
  type: ClusterIP
  selector:
    app: pod-nginx
  ports:
    - port: 80
      targetPort: 80

2.2 Ingress

2.2.1 部署Ingress Nginx Controllers

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访问https://github.com/kubernetes/ingress-nginx/tree/master/deploy/static/provider/baremetal

# 下载deploy.yaml，并做如下修改：
	注释创建services(273 - 300行)
	在Deployment中添加hostNetwork: true(在329行下面添加)

2.2.2 创建Ingress

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# 练习一
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: test-ingress
spec:
  backend:
    serviceName: test01
    servicePort: 80

# 练习二
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: name-virtual-host-ingress
spec:
  rules:
  - host: foo.bar.com
    http:
      paths:
      - backend:
          serviceName: test01
          servicePort: 80
  - host: bar.foo.com
    http:
      paths:
      - backend:
          serviceName: test02
          servicePort: 80

# 练习三
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: simple-fanout-example
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: foo.bar.com
    http:
      paths:
      - path: /foo
        backend:
          serviceName: test01
          servicePort: 80
      - path: /bar
        backend:
          serviceName: test02
          servicePort: 80