K8S-服务访问

1 Ingress简介

原理解析

Ingress是授权入站连接到达集群服务的规则集合。
    从外部流量调度到nodeport上的service
    从service调度到ingress-controller
    ingress-controller根据ingress[Pod]中的定义（虚拟主机或者后端的url）
    根据虚拟主机名直接调度到后端的一组应用pod中

2 Ingress部署

环境部署

获取配置文件
cd /data/kubernetes/app_secure
mkdir ingress ; cd ingress
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.3.1/deploy/static/provider/baremetal/deploy.yaml
mv deploy.yaml ingress-deploy.yaml
cp ingress-deploy.yaml{,.bak}

默认镜像
]# grep image: ingress-deploy.yaml | awk -F '/|@' '{print $(NF-1)}' | uniq
controller:v1.3.1
kube-webhook-certgen:v1.3.0

获取镜像
for i in nginx-ingress-controller:v1.3.1 kube-webhook-certgen:v1.3.0
do
  docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$i
  docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$i kubernetes-register.sswang.com/google_containers/$i
  docker push kubernetes-register.sswang.com/google_containers/$i
  docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$i
done
注意：
	controller的名称是需要更改一下，阿里云的镜像名称多了一个标识

修改基础镜像
]# grep image: ingress-deploy.yaml
          image: kubernetes-register.sswang.com/google_containers/nginx-ingress-controller:v1.3.1
          image: kubernetes-register.sswang.com/google_containers/kube-webhook-certgen:v1.3.0
          image: kubernetes-register.sswang.com/google_containers/kube-webhook-certgen:v1.3.0
  
开放访问入口地址  
]# vim ingress-deploy.yaml
...
334 apiVersion: v1
335 kind: Service
...
344   namespace: ingress-nginx
345 spec:
      ...
348   ipFamilyPolicy: SingleStack
349   externalIPs: ['10.0.0.12']			# 限制集群外部访问的入口ip
350   ports:
351   - appProtocol: http
352     name: http
353     port: 80
...
628   failurePolicy: Ignore				    # 为了避免默认的准入控制限制，改为Ignore
...

应用资源配置文件
]# kubectl apply -f ingress-deploy.yaml

确认效果
]# kubectl get all -n ingress-nginx
NAME                                            READY   STATUS      RESTARTS   AGE
pod/ingress-nginx-admission-create-s5p7h        0/1     Completed   0          105s
pod/ingress-nginx-admission-patch-qnjmv         0/1     Completed   0          105s
pod/ingress-nginx-controller-6cc467dfd9-c2dfg   1/1     Running     0          105s

NAME                                         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE
service/ingress-nginx-controller             NodePort    10.109.163.145   10.0.0.12     80:30439/TCP,443:31912/TCP   105s
service/ingress-nginx-controller-admission   ClusterIP   10.96.223.121    <none>        443/TCP                      105s

NAME                                       READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/ingress-nginx-controller   1/1     1            1           105s

NAME                                                  DESIRED   CURRENT   READY   AGE
replicaset.apps/ingress-nginx-controller-6cc467dfd9   1         1         1       105s

NAME                                       COMPLETIONS   DURATION   AGE
job.batch/ingress-nginx-admission-create   1/1           8s         105s
job.batch/ingress-nginx-admission-patch    1/1           7s         105s

测试访问页面
]# curl 10.0.0.12:30439
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx</center>
</body>
</html>

3 Ingress实践

定制资源清单文件

定制资源清单文件
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: superopsmsb-ingress-mulhost
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  rules:
  - host: nginx.sswang.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: sswang-nginx-web
            port:
              number: 80
  - host: tomcat.sswang.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: sswang-tomcat-web
            port:
              number: 8080