##Debian 6 安装server

# apt-get install nagios*

一路设置好各种密码,成功后访问 http://ip/nagios3 既可，默认用户*nagiosadmin*

##Centos 安装client

rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
yum -y install nagios nagios-plugins-all nrpe
chkconfig nrpe on

编辑配置文件 `nano /etc/nagios/nrpe.cfg`
将其中的`allowed_hosts`改为自己的值:

allowed_hosts=192.168.1.2 #server地址

重启nrpe:

service nrpe restart

##配置Server端

检测一下是否能连接到client:

/usr/lib/nagios/plugins/check_nrpe -H 192.168.2.11

进入`/etc/nagios3/conf.d`目录,新建并编辑`my_nagios2.cfg`:

define host{
use generic-host
host_name mylinux
alias mylinux
address 192.168.1.mylinux
}
define service{
use generic-service
host_name mylinux
service_description HTTP-Server
check_command check_http
}

# Define a service to check the disk space of the root partition
# on the local machine. Warning if 20 users, critical
# if > 50 users.

define service{
use generic-service ; Name of service template to use
host_name mylinux
service_description Current Users
check_command check_users!20!50
}

# Define a service to check the number of currently running procs
# on the local machine. Warning if > 250 processes, critical if
# > 400 processes.

define service{
use generic-service ; Name of service template to use
host_name mylinux
service_description Total Processes
check_command check_procs!250!400
}

# Define a service to check the load on the local machine.

define service{
use generic-service ; Name of service template to use
host_name mylinux
service_description Current Load
check_command check_load!5.0!4.0!3.0!10.0!6.0!4.0
}

重启服务:

service nagios3 restart

##添加Mysql监控插件

在server下载插件:
cd /usr/lib/nagios/plugins
wget https://raw.github.com/tart/tart-monitoring/master/checkMySQLProcesslist.sh
chmod a+x checkMySQLProcesslist.sh

向command配置`/etc/nagios3/commands.cfg`中添加:

define command{
command_name checkMySQLProcesslist
command_line /usr/lib/nagios/plugins/checkMySQLProcesslist.sh -u $ARG1$ -p $ARG2$ -s 60 -w 20 -c 50
}

向client配置`/etc/nagios3/conf.d/my_nagios2.cfg`中添加:
define service{
use generic-service
host_name localhost
service_description Mysql Process List
check_command checkMySQLProcesslist!用户名!密码
}

然后重启服务:

service nagios3 restart

##other

> Nagios的插件编写很简单，同上mysql的插件，照葫芦画瓢就行，添加其他client节点，只要安装好相应系统的nrpe和nagios的插件，然后在server段添加一个配置文件就行。