在使用lepus3.7监控MySQL数据库的时候，碰到了以下几个问题，本博客给出了这些问题产生的原因，以及相应的解决办法。

1. 问题1：php页面无法连接数据库

直接使用php程序执行php文件，可以连接mysql，但是在httpd中同样的php页面无法连接mysql。

lepus的web程序(PHP代码)无法连接数据库时，web界面上什么操作也无法继续。

为此编写了最简单的PDO连接测试代码：

php代码如下：

[linuxidc@linuxidc lepus]$ cat mysql.php

<?php

  try{

 #$dsn="mysql:host=127.0.0.1;dbname=lepus;";

 $dsn="mysql:host=11.1.1.11;dbname=lepus;";

 $user="coe2coe";

 $pwd="XXXXXXXXXX";

 $sql="select now() as a";

 $dbh=new PDO($dsn,$user,$pwd);

 $stmt=$dbh->prepare($sql);

 $stmt->execute();

 $row=$stmt->fetch(PDO::FETCH_ASSOC);

 echo "result:".$row['a'];

  }

  catch(PDOException $e) {

  echo  "FAILED:".$e->getMessage();

  }

?>

php程序直接执行php文件：

[linuxidc@linuxidc lepus]$ php mysql.php

result:2018-09-27 00:03:44

通过浏览器访问这个页面：

FAILED:SQLSTATE[HY000] [2003] Can't connect to MySQL server on '11.1.1.11' (13)

lepus的web程序给出的错误提示信息更加模糊。

原因：

通过一番baidu之后，终于看到了一个比较靠谱的分析。

[linuxidc@linuxidc lepus]$ sudo getsebool -a |grep httpd

httpd_anon_write --> off

httpd_builtin_scripting --> on

httpd_can_check_spam --> off

httpd_can_connect_ftp --> off

httpd_can_connect_ldap --> off

httpd_can_connect_mythtv --> off

httpd_can_connect_zabbix --> off

httpd_can_network_connect --> off

httpd_can_network_connect_cobbler --> off

httpd_can_network_connect_db --> off

httpd_can_network_memcache --> off

httpd_can_network_relay --> off

httpd_can_sendmail --> off

httpd_dbus_avahi --> off

httpd_dbus_sssd --> off

httpd_dontaudit_search_dirs --> off

httpd_enable_cgi --> on

httpd_enable_ftp_server --> off

httpd_enable_homedirs --> off

httpd_execmem --> off

httpd_graceful_shutdown --> on

httpd_manage_ipa --> off

httpd_mod_auth_ntlm_winbind --> off

httpd_mod_auth_pam --> off

httpd_read_user_content --> off

httpd_run_ipa --> off

httpd_run_preupgrade --> off

httpd_run_stickshift --> off

httpd_serve_cobbler_files --> off

httpd_setrlimit --> off

httpd_ssi_exec --> off

httpd_sys_script_anon_write --> off

httpd_tmp_exec --> off

httpd_tty_comm --> off

httpd_unified --> off

httpd_use_cifs --> off

httpd_use_fusefs --> off

httpd_use_gpg --> off

httpd_use_nfs --> off

httpd_use_openstack --> off

httpd_use_sasl --> off

httpd_verify_dns --> off

解决办法：

临时办法：临时禁用SELINUX。

[linuxidc@linuxidc lepus]$ sudo setenforce 0

永久办法：修改selinux配置文件，禁用SELINUX。

[linuxidc@linuxidc lepus]$ cat /etc/selinux/config

# This file controls the state of SELinux on the system.

# SELINUX= can take one of these three values:

#    enforcing - SELinux security policy is enforced.

#    permissive - SELinux prints warnings instead of enforcing.

#    disabled - No SELinux policy is loaded.

#SELINUX=enforcing

SELINUX=disabled

# SELINUXTYPE= can take one of three two values:

#    targeted - Targeted processes are protected,

#    minimum - Modification of targeted policy. Only selected processes are protected.

#    mls - Multi Level Security protection.

SELINUXTYPE=targeted

验证：

再次在浏览器中访问这个php页面：

result:2018-09-27 00:09:26

2. 问题2：lepus日志中出现group by警告。