nginx 负载均衡的配置方法

在 site-avaliable 新建一个配置项

两个服务器：

128.199.185.23:3000 (express)
128.199.86.27 (nginx)

express.conf :

    upstream express {
            server 128.199.185.23:3000;
            #server 128.199.185.24:3000
    }
    server {
            listen 3000;

            proxy_set_header Host  $host;
            proxy_http_version 1.1;

            location / {
                    proxy_pass http://express;
            }

    }

当其中一个服务不可用的时候，切换到下一个服务：

proxy_next_upstream     error timeout invalid_header http_500;
proxy_connect_timeout   2;

完整配置：

    upstream express {
            server 128.199.185.23:3000;
            server 128.199.185.24:3000;
    }
    server {
            listen 3000;

            proxy_set_header Host  $host;
            proxy_http_version 1.1;

            proxy_next_upstream     error timeout invalid_header http_500;
            proxy_connect_timeout   2;

            location / {
                    proxy_pass http://express;
            }
    }