客户端操作：
yum install -y nagios-plugins nagios-plugins-all nrpe nagios-plugins-nrpe#安装
vim /etc/nagios/nrpe.cfg #更改客户端的nrpe配置文件
allowed_hosts=192.168.20.168 #IP更改成监控端的地址，如果是多个使用,分割开
#漏了这个后期会出现CHECK_NRPE: Error - Could not complete SSL handshake. 的
vim /usr/lib64/nagios/plugins/check_slave #编辑监控脚本
#!/bin/sh
slave_R=($(/usr/local/mysql/bin/mysql -e "show slave status\G"|grep Running |awk ‘{print $2}‘))
if [ "${slave_R[0]}" = "Yes" -a "${slave_R[1]}" = "Yes" ]
then
echo "OK RN2-slave is running"
exit 0
else
echo "Critical RN2-slave is error"
exit 2
fi
chmod +x /usr/lib64/nagios/plugins/check_slave #加上可执行权限，否则NRPE: Unable to read output
vim /etc/nagios/nrpe.cfg #编辑nrpe.cfg，加上如下：
command[check_slave]=/usr/lib64/nagios/plugins/check_slave
执行监控脚本：
sh /usr/lib64/nagios/plugins/check_slave #输出OK
/etc/init.d/nrpe start #启动nrpe
服务端：
vim /etc/nagios/conf.d/192.168.20.130.cfg
define host{
use linux-server
host_name 192.168.20.130
alias 20.130
address 192.168.20.130
}
define service{
use generic-service
host_name 192.168.20.130
service_description check_slave
check_command check_nrpe!check_slave
max_check_attempts 2
normal_check_interval 2
contact_groups common
notifications_enabled 1
notification_period 24x7
notification_options w,u,c,r
}
nagios -v /etc/nagios/nagios.cfg #检查脚本，无错，继续下一步
/etc/init.d/nagios restart
登陆监控查看：
停掉客户端的mysql，查看：
收到告警邮件：
恢复mysql的slave端至正常收；收到恢复到正常的邮件了：
