[pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 0 idle, and 12 total children
编辑以下内容,调大一下,start_servers和max_spare_servers 可以避免一定情况下的502频繁错误.
文件在/usr/local/php/etc/php-fpm.conf