nagios系列(七)nagios通过自定义脚本的方式监控mysql主从同步

nagios监控mysql主从同步



起因：nagios可能监控到mysql服务的运行情况，但确不能监控mysql的主从复制是否正常：有时候，同步已经停止，但管理人员却不知道。

登陆mysql从服务器，通过执行 mysql> show slave status/G 查看其输出，即可判定主从复制是否正常。下面是某个从服务器的输出：

mysql> show slave status\G

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.8.40

Master_User: repluser

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: mysql-bin.000008

Read_Master_Log_Pos: 34797869

Relay_Log_File: relay-bin.000003

Relay_Log_Pos: 34797915

Relay_Master_Log_File: mysql-bin.000008

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

Replicate_Do_DB:

Replicate_Ignore_DB:

Replicate_Do_Table:

Replicate_Ignore_Table:

Replicate_Wild_Do_Table: TD_OA.%

Replicate_Wild_Ignore_Table: mysql.%

Last_Errno: 0

Last_Error:

Skip_Counter: 0

Exec_Master_Log_Pos: 34797869

Relay_Log_Space: 34798311

Until_Condition: None

Until_Log_File:

Until_Log_Pos: 0

Master_SSL_Allowed: No

Master_SSL_CA_File:

Master_SSL_CA_Path:

Master_SSL_Cert:

Master_SSL_Cipher:

Master_SSL_Key:

Seconds_Behind_Master: 0

Master_SSL_Verify_Server_Cert: No

Last_IO_Errno: 0

Last_IO_Error:

Last_SQL_Errno: 0

Last_SQL_Error:

Replicate_Ignore_Server_Ids:

Master_Server_Id: 1

1 row in set (0.00 sec)

这个输出，最关键处就是"Slave_IO_Running: Yes “和“Slave_SQL_Running: Yes ”，这两个值全是"Yes"就表明主从复制正常，否则就是有问题。

操作步骤：

1、在从数据库服务器增加一个用户，给予较低的权限，操作为

mysql> grant replication client on *.* to 'nagios'@'%' identified by 'nagios';

mysql> flush privileges;

2、登陆主服务器验证一下，看是否正常。操作为

/usr/local/mysql/bin/mysql -h192.168.8.45 -unagios -pnagios -e "show slave status\G"

注意：这个操作是在 shell下操作的

3、在从服务器安装 nrpe,然后在配置文件/usr/local/nagios/etc/nrpe.cfg加入一行

command[check_mysql_slave]=/usr/local/nagios/libexec/check_mysql_slave

4、在nagios client端即mysql从服务器编写脚本vim /usr/local/nagios/libexec/check_mysql_slave（这是监控其作用的核心）,其内容如下：

#!/bin/sh

declare -a slave_is

slave_is=($(/usr/local/mysql/bin/mysql -unagios -pnagios -e "show slave status\G"|grep Running |awk '{print $2}'))

if [ "${slave_is[0]}" = "Yes" -a "${slave_is[1]}" = "Yes" ]

then

echo "OK -slave is running"

exit 0

else

echo "Critical -slave is error"

exit 2

fi

chmod +x /usr/local/nagios/libexec/check_mysql_slave

5、手动运行这个脚本，观察输出。

# /usr/local/mysql/bin/mysql -unagios -pnagios -e "show slave status\G"|grep Running |awk '{print $2}'

报错：

ERROR 1045 (28000): Access denied for user 'nagios'@'localhost' (using password: YES)

发现删除系统mysql库中user表自带的一些'::1'等匿名用户，并且对root配置密码后，问题解决

6、nagios服务端执行

# /usr/local/nagios/libexec/check_nrpe -H 192.168.8.45 -c check_mysql_slave

OK -slave is running

7、修改nagios服务端service.cfg文件。

/usr/local/nagios/etc/objects/service.cfg

添加

define service{

use generic-service

host_name node45.chinasoft.com

service_description check_mysql_slave

check_command check_nrpe!check_mysql_slave

}

8、功能测试