Nginx 根据上游服务器更改标头

Question

我的环境中有 nginx 代理和 2 个上游（主上游服务器和备份上游服务器）服务器，目标是根据所选的上游来更改“proxy_set_header Host X/Y”。

现在我只有一个想法，创建另一个 nginx 实例并将所有请求从我的代理发送到该实例，重写标头并进一步发送请求。

有谁知道更方便的解决方案吗？

这是我的简化配置：

http {
access_log  /var/log/nginx/access.log  main;

sendfile            on;
tcp_nopush          on;
tcp_nodelay         on;
keepalive_timeout   65;
types_hash_max_size 2048;

include             /etc/nginx/mime.types;
default_type        application/octet-stream;

include /etc/nginx/conf.d/*.conf;

upstream images {
   server backend.test.com:8080 ;
   server backend-backup.test.com:8090 backup;
 }

server {
    listen       80 default_server;
    server_name  images-test.test.com;
    root         /usr/share/nginx/html;

    include /etc/nginx/default.d/*.conf;
 
    add_header                          Last-Modified "";
    add_header                          Pragma "public";
    add_header                          Access-Control-Allow-Origin $http_origin;

    error_page 404 /404.html;
    location = /404.html {}

    error_page 500 502 503 504 /50x.html;
    location = /50x.html {}


    location / {
  # some not related to the question lines deleted
          proxy_set_header Host "backend.test.com";
          proxy_pass http://images;
        }
}

}