[mcj]nginx服务器提示：502 Bad Gateway解决方法

Nginx服务器网站打开之后出现：

502 Bad Gateway
nginx

经测试，是php的问题，首先看一下使用的php版本

然后测试该版本php是否启动：

(base) mcj@mcj2080:/usr/include$ service php-fpm-56 status
 php-fpm-56.service - LSB: starts php-fpm
   Loaded: loaded (/etc/init.d/php-fpm-56; bad; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:systemd-sysv-generator(8)

我们可以看到，php5.6并没有启动，所以我们只需要将其启动即可。

sudo service php-fpm-56 start

这个时候我们再看一下状态：

(base) mcj@mcj2080:/usr/include$ service php-fpm-56 status
\u25cf php-fpm-56.service - LSB: starts php-fpm
   Loaded: loaded (/etc/init.d/php-fpm-56; bad; vendor preset: enabled)
   Active: active (running) since \u4e00 2019-07-01 11:34:20 CST; 1s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 14186 ExecStart=/etc/init.d/php-fpm-56 start (code=exited, status=0/SUCCESS)
    Tasks: 21
   Memory: 22.0M
      CPU: 49ms
   CGroup: /system.slice/php-fpm-56.service
           \u251c\u250014202 php-fpm: master process (/www/server/php/56/etc/php-fpm.conf)                                                                            
           \u251c\u250014204 php-fpm: pool www                                                                                                                        
           \u251c\u250014205 php-fpm: pool www                                                                                                                        
           \u251c\u250014206 php-fpm: pool www                                                                                                                        
           \u251c\u250014207 php-fpm: pool www                                                                                                                        
           \u251c\u250014209 php-fpm: pool www                                                                                                                        
           \u251c\u250014210 php-fpm: pool www                                                                                                                        
           \u251c\u250014211 php-fpm: pool www                                                                                                                        
           \u251c\u250014212 php-fpm: pool www                                                                                                                        
           \u251c\u250014213 php-fpm: pool www                                                                                                                        
           \u251c\u250014214 php-fpm: pool www                                                                                                                        
           \u251c\u250014215 php-fpm: pool www                                                                                                                        
           \u251c\u250014216 php-fpm: pool www                                                                                                                        
           \u251c\u250014217 php-fpm: pool www                                                                                                                        
           \u251c\u250014218 php-fpm: pool www                                                                                                                        
           \u251c\u250014219 php-fpm: pool www                                                                                                                        
           \u251c\u250014220 php-fpm: pool www                                                                                                                        
           \u251c\u250014221 php-fpm: pool www                                                                                                                        
           \u251c\u250014222 php-fpm: pool www                                                                                                                        
           \u251c\u250014223 php-fpm: pool www                                                                                                                        
           \u2514\u250014224 php-fpm: pool www                                                                                                                        

7\u6708 01 11:34:20 mcj2080 systemd[1]: Starting LSB: starts php-fpm...
7\u6708 01 11:34:20 mcj2080 php-fpm-56[14186]: Starting php-fpm  done
7\u6708 01 11:34:20 mcj2080 systemd[1]: Started LSB: starts php-fpm.

OK，已经正常启动了，此时再打开网站，可以发现已经正常了！