k8s之ingress及ingress controller

1.ingress概述

图解:第一个service起到的作用是:引入外部流量,也可以不用此方式,以DaemonSet控制器的方式让Pod共享节点网络,第二个service的作用是:对后端pod分组,不被调度时使用,如果后端pod发生变动,则ingress就会将变动信息注入到,ingress controller管理的7层负载nginx的配置文件中.

2.部署

wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/mandatory.yaml
kubectl apply -f mandatory.yaml
# 之前还有个default-http-backend,现在只运行一个pod
kubectl get pods -n ingress-nginx
NAME                                        READY   STATUS    RESTARTS   AGE
nginx-ingress-controller-689498bc7c-sm972   1/1     Running   0          45s

# nginx-ingress-controller部署在node1上,一个deployment控制器,一个replicaset,一个pod.
# 接下来还需要部署一个service-nodeport服务,才能实现把集群外部流量接入到集群中来.
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml
# 为了不让service nodeport自动分配端口,需要手动指定nodeport
cat service-nodeport.yaml
apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: NodePort
  ports:
    - name: http
      port: 80
      targetPort: 80
      nodePort: 30080
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
      nodePort: 30443
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

kubectl apply -f service-nodeport.yaml
kubectl get svc -n ingress-nginx
NAME            TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx   NodePort   10.102.228.59   <none>        80:30080/TCP,443:30443/TCP   31s

3.定义后端分组service:myapp-svc

cat myapp-svc-headless.yaml
apiVersion: v1
kind: Service
metadata:
  name: myapp-svc
  namespace: default
spec:
  selector:
    app: myapp
    release: canary
  clusterIP: "None"
  ports:
  - port: 80
    targetPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deploy
  namespace: default
spec:
  replicas: 2
  selector:
    matchLabels:
      app: myapp
      release: canary
  template:
    metadata:
      labels:
        app: myapp
        release: canary
    spec:
      containers:
      - name: myapp
        image: ikubernetes/myapp:v1
        ports:
        - name: http
          containerPort: 80
# 创建pod时,用nodeSelector可实现精准分布
kubectl apply -f myapp-svc-headless.yaml
kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   13d
myapp-svc    ClusterIP   None         <none>        80/TCP    29m

# 通过Ingress把myapp-svc发布出去
cat ingress-myapp.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-myapp
  namespace: default
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  rules:
  - host: myapp.lixiang.com
    http:
      paths:
      - path:
        backend:
          serviceName: myapp-svc
          servicePort: 80

namespace要和deployment和要发布的service处于同一个名称空间
annotations:说明我们要用到的ingress-controller是nginx,而不是Traefik、Envoy
host:表示访问这个域名,就会转发到后端myapp-deploy管理的pod上
kubectl apply -f ingress-myapp.yaml
kubectl get ingress
NAME            HOSTS               ADDRESS   PORTS   AGE
ingress-myapp   myapp.lixiang.com             80      5m34s
#  进入交互式命令行
kubectl exec -n ingress-nginx -it nginx-ingress-controller-689498bc7c-sm972 -- /bin/sh
$ cat nginx.conf
	## start server myapp.lixiang.com
	server {
		server_name myapp.lixiang.com ;
		listen 80;
		location / {
			set $namespace      "default";
			set $ingress_name   "ingress-myapp";
			set $service_name   "myapp-svc";
			set $service_port   "80";
			set $location_path  "/";
# ingress一经创建,就将信息注入到nginx-ingress-controller这个pod中,
# 个人感觉ingress像一个监视者、搬运工,nginx-ingress-controller起到反向代理的作用
# 添加一条hosts解析
curl myapp.lixiang.com:30080
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

4.使用https访问

# 自签证书
openssl genrsa -out tls.key 2048
openssl req -new -x509 -key tls.key  -out tls.crt -subj /C=CN/ST=Beijing/O=DevOps/CN=myapp.lixiang.com
# 通过secret把证书注入到pod中
kubectl create secret tls myapp-infress-secret --cert=tls.crt --key=tls.key
cat ingress-myapp.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-myapp-tls
  namespace: default
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  tls:
  - hosts:
    - myapp.lixiang.com
    secretName: myapp-infress-secret
  rules:
  - host: myapp.lixiang.com
    http:
      paths:
      - path: /
        backend:
          serviceName: myapp-svc
          servicePort: 80
# 进入容器查看配置文件
cat nginx.conf
server {
	server_name myapp.lixiang.com ;
	listen 80;
	listen 443  ssl http2;
curl -k https://myapp.lixiang.com:30443

参考博客:http://blog.itpub.net/28916011/viewspace-2214747/