我一直在nginx.error.log中收到此错误：

2016/06/06 20:14:02 [error] 907#0: *1 connect() to unix:///home/user/apps/appname/shared/tmp/sockets/appname-puma.sock failed (111: Connection refused) while connecting to upstream, client: 50.100.162.19, server: , request: "GET / HTTP/1.1", upstream: "http://unix:///home/user/apps/appname/shared/tmp/sockets/appname-puma.sock:/", host: "appname.com"

(here it is with manually added newlines for your convenience)
2016/06/06 20:14:02 [error] 907#0: *1 connect() to
unix:///home/user/apps/appname/shared/tmp/sockets/appname-puma.sock failed
(111: Connection refused) while connecting to upstream, client: 
50.100.162.19, server: , request: "GET / HTTP/1.1", upstream: 
"http://unix:///home/user/apps/appname/shared/tmp/sockets/appname-
puma.sock:/", host: "appname.com"

这是我的nginx.conf：

upstream puma {
  server unix:///home/user/apps/appname/shared/tmp/sockets/appname-puma.sock;
}

server {
  listen 80 default_server deferred;
  # server_name example.com;

  root /home/user/apps/appname/current/public;
  access_log /home/user/apps/appname/current/log/nginx.access.log;
  error_log /home/user/apps/appname/current/log/nginx.error.log info;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @puma;
  location @puma {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;

    proxy_pass http://puma;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 10M;
  keepalive_timeout 10;
}

我究竟做错了什么？
我跟着Digital Ocean’s tutorial设立了Capistrano,Nginx和Puma.

解决方法:

所以解决方案是重启puma.

cap production deploy:restart

每次我重启服务器,我都需要重启puma.