apache无法启动，提示：
正在启动 httpd：httpd: apr_sockaddr_info_get() failed for CentOS
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName原因：httpd.conf文件中未设置ServerName
解决方法：在httpd.conf文件中找到#ServerName www.example.com:80，去掉注释，将www.example.com:80改为本机IP:80