启动php-fpm时报错： Starting php-fpm ERROR: [pool www] cannot get uid for user 'nginx'

启动 php-fpm 时报错：

Starting php-fpm [23-May-2018 12:20:45] ERROR: [pool www] cannot get uid for user 'nginx'

意思是没有nginx用户，添加就好了

# useradd nginx