每次打开电脑时，我的 nginx 都没有激活：
? nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Qui 2017-07-27 07:11:02 BRT; 59s ago
Process: 1006 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
Jul 27 07:11:01 note-gui systemd[1]: Starting A high performance web server and a reverse proxy server...
Jul 27 07:11:02 note-gui nginx[1006]: nginx: [emerg] host not found in upstream "localhost" in /etc/nginx/sites-enabled/default:27
Jul 27 07:11:02 …nginx ×1