使用supervisor守护frpc客户端进程，确保开机自启端口，记录报错过程。
报错1：[centos@localhost supervisor]$ sudo supervisord
/usr/lib/python2.7/site-packages/supervisor/options.py:461: UserWarning: Supervisord is running as root and it is searching for its configuration file in default locations (including its current working directory); you probably want to specify a "-c" argument specifying an absolute path to a configuration file for improved security.
'Supervisord is running as root and it is searching '
解决：按照上面的提示，用supervisord 直接启动supervisor 会引起报错，故第一次启动的时候要加上配置文件。
[centos@localhost supervisor]$ sudo supervisord -c /etc/supervisord.conf
报错2：[centos@localhost supervisor]$ sudo supervisord -c /etc/supervisord.conf
Unlinking stale socket /var/run/supervisor/supervisor.sock
解决：
[centos@localhost supervisor]$ unlink /var/run/supervisor/supervisor.sock
报错3：[centos@localhost supervisord.d]$ sudo supervisorctl status
unix:///var/run/supervisor/supervisor.sock no such file
解决：
1.需改权限
sudo chmod 777 /run
sudo chmod 777 /var/log
2.创建supervisor.sock文件
[centos@localhost supervisord.d]$ sudo touch /var/run/supervisor/supervisor.sock
[centos@localhost supervisord.d]$ sudo chmod 777 /var/run/supervisor/supervisor.sock
3.重启
[centos@localhost supervisor]$ sudo supervisord -c /etc/supervisord.conf
报错4：[centos@localhost supervisor]$ sudo supervisord -c /etc/supervisord.conf
Error: Another program is already listening on a port that one of our HTTP servers is configured to use. Shut this program down first before starting supervisord.
For help, use /bin/supervisord -h
解决：
[centos@localhost supervisor]$ ps -ef | grep supervisord #查看supervisord进程
root 13000 1 0 16:59 ? 00:00:00 /usr/bin/python /bin/supervisord
centos 13347 3471 0 17:00 pts/0 00:00:00 grep --color=auto supervisord
[centos@localhost supervisor]$ sudo kill -s SIGTERM 13000 #杀死进程
[centos@localhost supervisor]$ ps -ef | grep supervisord #确认进程supervisord被杀死
centos 13664 3471 0 17:01 pts/0 00:00:00 grep --color=auto supervisord
[centos@localhost supervisor]$ sudo supervisord -c /etc/supervisord.conf #启动新的supervisord进程
记得设置开机自启：systemctl enable supervisord
验证：systemctl is-enabled supervisord
结束。