查看log：
NG出现502 upstream sent too big header while reading response header from upstream
搜索了很多文章，找到了一个正确的：
location ~ \.php$ {
fastcgi_buffer_size 128k;
fastcgi_buffers 32 32k;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
include fcgi.conf;
}
就是上面加粗的部分！
记录一下而已