k8s的Ingress

一.Ingress简介

外部访问集群内的服务,可以通过NodePort或LoadBalancer(这通常由云服务商提供),还可以通过ingress访问.

Ingress包含两个组件Ingress Controller和Ingress：

Ingress:将Nginx的配置抽象成一个Ingress对象，每添加一个新的服务只需写一个新的Ingress的yaml文件即可
Ingress Controller:将新加入的Ingress转化成Nginx的配置文件并使之生效

二.安装和配置

1.官方文档:

https://kubernetes.github.io/ingress-nginx/deploy/

2.创建并应用default-backend.yaml

default-backend的作用是，如果外界访问的域名不存在的话，则默认转发到default-http-backend这个Service，其会直接返回404：

[root@master ingress]# cat default-backend.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: default
  labels:
    k8s-app: default-http-backend
  namespace: default
spec:
  replicas: 1
  template:
    metadata:
      labels:
        k8s-app: default-http-backend
    spec:
      terminationGracePeriodSeconds: 60
      containers:
      - name: default-http-backend
        # Any image is permissable as long as:
        # 1. It serves a 404 page at /
        # 2. It serves 200 on a /healthz endpoint
        image: anjia0532/defaultbackend:1.0
        livenessProbe:
          httpGet:
            path: /healthz
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 30
          timeoutSeconds: 5
        ports:
        - containerPort: 8080
        resources:
          limits:
            cpu: 10m
            memory: 20Mi
          requests:
            cpu: 10m
            memory: 20Mi
---
apiVersion: v1
kind: Service
metadata:
  name: default-http-backend
  namespace: default
  labels:
    k8s-app: default-http-backend
spec:
  ports:
  - port: 80
    targetPort: 8080
  selector:
    k8s-app: default-http-backend

[root@master ingress]#kubectl create -f default-backend.yaml

　　

2.创建并应用nginx-ingress-controller.yaml

[root@master ingress]# cat nginx-ingress-controller.yaml
apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx-ingress-lb
  labels:
    name: nginx-ingress-lb
  namespace: default
spec:
  replicas: 1
  template:
    metadata:
      labels:
        name: nginx-ingress-lb
      annotations:
        prometheus.io/port: '10254'
        prometheus.io/scrape: 'true'
    spec:
      terminationGracePeriodSeconds: 60
      hostNetwork: true
      containers:
      - image: anjia0532/nginx-ingress-controller:0.9.0-beta.7
        name: nginx-ingress-lb
        readinessProbe:
          httpGet:
            path: /healthz
            port: 10254
            scheme: HTTP
        livenessProbe:
          httpGet:
            path: /healthz
            port: 10254
            scheme: HTTP
          initialDelaySeconds: 10
          timeoutSeconds: 1
        ports:
        - containerPort: 80
          hostPort: 80
        - containerPort: 443
          hostPort: 443
        env:
          - name: POD_NAME
            valueFrom:
              fieldRef:
                fieldPath: metadata.name
          - name: POD_NAMESPACE
            valueFrom:
              fieldRef:
                fieldPath: metadata.namespace
          - name: KUBERNETES_MASTER
            value: http://192.168.2.17:8080
        args:
        - /nginx-ingress-controller
        - --default-backend-service=$(POD_NAMESPACE)/default-http-backend
        - --apiserver-host=http://192.168.2.17:8080

[root@master ingress]#kubectl create -f nginx-ingress-controller.yaml

　　

ps:
注意以上master地址,需要配置成正确的地址

三.自定义Ingress

1.创建并应用test.nginx.ingress

[root@master ingress]# cat test-nginx-ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: test-nginx-ingress
  namespace: default
spec:
  rules:
  - host: test.nginx.ingress
    http:
      paths:
      - path: /
        backend:
          serviceName: nginx-service
          servicePort: 80

[root@master ingress]#kubectl create -f test-nginx-ingress.yaml

　　

rules中的host必须为域名，不能为IP，表示Ingress-controller的Pod所在主机域名，也就是Ingress-controller的IP对应的域名。
paths中的path则表示映射的路径。如映射/表示若访问test.nginx.ingress，则会将请求转发至Kibana的service，端口为5601。

2.查看创建的ingress

[root@master ingress]# kubectl get ingress -o wide
NAME                         HOSTS                ADDRESS        PORTS     AGE
dashboard-weblogic-ingress   test.nginx.ingress   192.168.2.26   80        2m

　　

我们通过以下命令将pod中nginx的配置文件输出到当前目录下看看

kubectl exec nginx-ingress-lb-6glds -it cat /etc/nginx/nginx.conf > nginx.conf

可以看到是一个标准的nginx配置文件

3.验证

#curl -H "Host:test.nginx.ingress"  192.168.2.26/a.html

如果正常,即可输出结果