使用代理时 Nginx 502 Bad Gateway 错误

我有一个 Angular 构建和一个 Laravel 后端，提供在一台服务器上运行的 API。我已经在 nginx 中配置了它们，前端有一个到后端服务器的代理。

后端在 url 上运行（示例是占位符）http://api.example.com http://api.example.com并且前端正在运行http://example.com http://example.com

前端配置：

server {
    listen       80;
    server_name  example.com;

    location /api {
        proxy_pass http://api.example.com;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
    }

    location / {
        root  /var/www/angular/em-frontend/dist;
        index  index.html index.htm;
        try_files $uri $uri/ /index.html$is_args$args;
    }
}

后端配置：

server {
        listen 80;
        server_name api.example.com;

        root /var/www/angular/em-backend/public;

        index index.php index.html index.htm;

        location / {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
                try_files $uri $uri/ /index.php?$query_string;
                # Uncomment to enable naxsi on this location
                # include /etc/nginx/naxsi.rules
        }
        location ~ \.php$ {
                try_files $uri =404;
                fastcgi_split_path_info ^(.+\.php)(/.+)$;
                fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
                fastcgi_index index.php;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                include fastcgi_params;
        }
}

现在，当我从前端执行任何 api 调用时，我会收到来自 nginx 的 502 Bad Gateway 错误。

从 nginx 错误日志：

2017/12/09 23:30:40 [alert] 5932#5932: 768 worker_connections are not enough
2017/12/09 23:30:40 [error] 5932#5932: *770 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: IP_MASKED, server: example.com, request: "GET /api/endpoint HTTP/1.1", upstream: "http://IP_ADDRESS:80/api/endpoint", host: "example.com", referrer: "http://example.com/dashboard"

知道我该如何解决这个问题吗？

您必须在位置块中使用 proxy-pass，如下例所示：

upstream myproject {
   server ip1 ;
   server ip2 ;
   server ip3 ;

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