NGINX Ingress Controller 设置未配置过的域名增加默认路由

背景

k8s 集群对应的公网 slb ip 经常被人绑定域名，监控侧经常会收集到 502 相关状态码的异常告警，着手处理这种bad case

策略

1.  所有没有在ingress 配置过的域名要进行处理，即不是公司的、非法绑定到slb 上的域名要加上一条策略
2. NGINX Ingress Controller 设置未配置过的域名增加一条默认路由，指向一个固定的服务

方法

• Dockerfile

#cat Dockerfile 
FROM nginx:latest #一个nginx镜像即可
ADD defalut.conf /opt/openresty/nginx/conf/vhost/  #拷贝一个nginx 自定义的配置文件进去
RUN mkdir /export/html  #创建 404 图片放置的目录
COPY 404.jpeg /export/html/  #拷贝一张随意的404 图片
EXPOSE 80
CMD ["/opt/openresty/nginx/sbin/nginx","-g","daemon off;"]

• default.conf 配置文件

#cat defalut.conf 
server {
    listen       80;
    server_name  localhost;

    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;
    location / {
        root   /user/share/nginx/html;  #目录不用创建，且该目录也不用存在
        index  index.html index.htm;
        error_page  404              /404.jpeg; #定义404 的方法
        proxy_set_header HOST   $host;
        proxy_set_header X-Real-IP      $remote_addr;
        proxy_set_header X-Forwarded-FOR $proxy_add_x_forwarded_for;
    }

     location = /404.jpeg { #处理404 的方法
       root  /export/html;
     }

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}

• 打镜像
• 准备yaml 配置文件

# cat default-dp.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: default-backend
  namespace: default-backend
spec:
  replicas: 1
  selector:
    matchLabels:
      app: default-backend
  template:
    metadata:
      labels:
        app: default-backend
    spec:
      containers:
        - name: default-backend
          image: registry-vpc.cn-xxx.aliyuncs.com/xxx/nginx:default-server-v002
          ports:
            - containerPort: 80


# cat default-svc.yaml 
apiVersion: v1
kind: Service
metadata:
  name: default-backend
  namespace: default-backend
spec:
  selector:
    app: default-backend
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80

# cat default-ingress.yaml  (nginx.ingress.kubernetes.io/default-backend注解，并结合*通配符来匹配所有未配置的域名)
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  namespace: default-backend
  annotations:
    nginx.ingress.kubernetes.io/default-backend: default-backend
spec:
  rules:
  - http:
      paths:
      - backend:
          service:
            name: default-backend
            port:
              number: 80
        path: /
        pathType: Prefix

• 生成配置文件

# kubectl apply  -f default-dp.yaml 
# kubectl apply  -f default-svc.yaml 
# kubectl apply  -f default-ingress.yaml

• 查看 ingress (* nginx.ingress.kubernetes.io/default-backend注解，并结合*通配符来匹配所有未配置的域名 )

# kubectl  get ingress -n default-backend 
NAME              CLASS   HOSTS   ADDRESS       PORTS   AGE
example-ingress   nginx   *       172.16.4.41   80      3h37m

• 本地访问测试

# 随意一个域名绑定到k8s 对外的slb 地址上，显示 404 的图片