nginx 代理之修改header 的HOST，实现代理转代理

现有一个需求，需要从nginx跳转到k8s的traefik代理上，从而实现服务的访问，用于测试。直接修改proxy_set_header的HOST，修改为traefuk代理的域名，proxy_pass是traefik的代理地址.

server {
listen 80;
server_name kbe.get.com;
location /api {
#auth_basic "it's protected";
#auth_basic_user_file /data/.htpassd;
proxy_pass http://10.1.2.9;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host feature-distinct-kube.app.com;
}
}

解决跨域问题：

在location段添加如下内容：

　　if ($request_method = 'OPTIONS') {

   　　add_header 'Access-Control-Allow-Origin' '*';

　　   add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';

　　　# # Custom headers and headers various browsers *should* be OK with but aren't

        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';

       # # Tell client that this pre-flight info is valid for 20 days

       add_header 'Access-Control-Max-Age' 1728000; add_header 'Content-Type' 'text/plain charset=UTF-8';

       add_header 'Content-Length' 0;

       return 204; }

   if ($request_method = 'POST') {

     add_header 'Access-Control-Allow-Origin' '*';

     add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';

     add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type'; }

  if ($request_method = 'GET') {

     add_header 'Access-Control-Allow-Origin' '*';

     add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';

     add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type'; }