ubuntu服务器重启后，nginx 502网关错误

我遇到了配置为与Nginx和fastcgi一起运行的ubuntu服务器的情况.问题在于，重新启动后，任何请求都会在浏览器中提供502错误的网关.

I have a situation with an ubuntu server that is configured to run with nginx and fastcgi. The problem is that after a restart any request is giving 502 bad gateway in browser.

在错误日志中，错误看起来像这样:

In error log the error looks like this:

 connect() to unix:/var/run/fastcgi.socket-4 failed (2: No such file or directory) while connecting to upstream

在我手动创建文件后(我不知道这是否正确)，错误更改为:

after I create the file manually (i do not know if this is correct) the error is changing to:

connect() to unix:/var/run/fastcgi.socket-4 failed (111: Connection refused) while connecting to upstream

nginx服务器具有每个网站的配置设置，如下所示:

nginx server has configuration settings for each website like this:

 location ~ \.php$ {
                        fastcgi_pass                    unix:/var/run/fastcgi.socket-4;
                        fastcgi_param   GATEWAY_INTERFACE       CGI/1.1;
                        fastcgi_param   SERVER_SOFTWARE         nginx;
                        fastcgi_param   QUERY_STRING            $query_string;
                        fastcgi_param   REQUEST_METHOD          $request_method;
                        fastcgi_param   CONTENT_TYPE            $content_type;
                        fastcgi_param   CONTENT_LENGTH          $content_length;
                        fastcgi_param   SCRIPT_FILENAME         /document_root/$fastcgi_scr
                        fastcgi_param   SCRIPT_NAME             $fastcgi_script_name;
                        fastcgi_param   REQUEST_URI             $request_uri;
                        fastcgi_param   DOCUMENT_URI            $document_uri;
                        fastcgi_param   DOCUMENT_ROOT           /document_root;
                        fastcgi_param   SERVER_PROTOCOL         $server_protocol;
                        fastcgi_param   REMOTE_ADDR             $remote_addr;
                        fastcgi_param   REMOTE_PORT             $remote_port;
                        fastcgi_param   SERVER_ADDR             $server_addr;
                        fastcgi_param   SERVER_PORT             $server_port;
                        fastcgi_param   SERVER_NAME             $server_name;
                        fastcgi_param   REDIRECT_STATUS         200;
                        fastcgi_index                   index.php;
                        fastcgi_intercept_errors        on;
                        }

请注意，我对nginx还是很陌生，但是我在apache和php中有经验和专业知识.

Note that I am quite new to nginx, however I have experience and knowhow in apache and php.