Configure new Nagios clients

1. 安装
   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 install -y gcc glibc glibc-common gd gd-devel make net-snmp openssl-devel xinetd bc
   安装nagios插件
   yum -y install nagios-plugins-all nagios-plugins-nrpe
   nagios-plugins目录：/usr/lib64/nagios/plugins/
   安装nrpe
   yum -y install nrpe
2. 修改nrpe设置
   vi /etc/nagios/nrpe.cfg
   only_from = 127.0.0.1,Server_IP
3. 修改防火墙设置
   添加5666端口，重启iptables
4. 修改services服务
   vi /etc/services
   添加
   nrpe            5666/tcp                # NRPE
   service xinetd restart
5. 测试nrpe是否安装成功
   cd /usr/lib64/nagios/plugins/
   ./check_nrpe -H 127.0.0.1
   若提示失败，可能是nrpe未安装或nrpe.cfg配置文件设置错误导致
6. 修改nrpe.cfg
   vi /etc/nagios/nrpe.cfg
   注释掉目录不存在的nagios插件命令
   

   #command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10
   #command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
   #command[check_hda1]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/hda1
   #command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z
   #command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 150 -c 200
   
   
   command[check_users]=/usr/lib64/nagios/plugins/check_users -w 5 -c 10
   command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20
   command[check_sda1]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /dev/sda1
   command[check_zombie_procs]=/usr/lib64/nagios/plugins/check_procs -w 5 -c 10 -s Z
   command[check_total_procs]=/usr/lib64/nagios/plugins/check_procs -w 150 -c 200

   测试命令是否能够执行
   cd /usr/lib64/nagios/plugins/
   ./check_nrpe -H 127.0.0.1 -c check_users
   ./check_nrpe -H 127.0.0.1 -c check_load
   ./check_nrpe -H 127.0.0.1 -c check_sda1
   ./check_nrpe -H 127.0.0.1 -c check_zombie_procs
   ./check_nrpe -H 127.0.0.1 -c check_total_procs

7. 配置Nagios监控端服务器
   cd /usr/lib64/nagios/plugins/
   ./check_nrpe -H Remote_linux_ip_address(被监控的ServerIP)
   显示 NRPE v2.15 即正常
   cd /etc/nagios/objects
   touch hosts.cfg touch services.cfg
   vi hosts.cfg 注意修改IP
   

   ## Default Linux Host Template ##
   define host{
   name                            linux-box               ; Name of this template
   use                             generic-host            ; Inherit default values
   check_period                    24x7
   check_interval                  5
   retry_interval                  1
   max_check_attempts              10
   check_command                   check-host-alive
   notification_period             24x7
   notification_interval           30
   notification_options            d,r
   contact_groups                  admins
   register                        0                       ; DONT REGISTER THIS - ITS A TEMPLATE
   }
   
   ## Default
   define host{
   use                             linux-box               ; Inherit default values from a template
   host_name                       Nagios_Centos_Client1                   ; The name we're giving to this server
   alias                           CentOS 6                ; A longer name for the server
   address                         remote_linux_ip_address            ; IP address of Remote Linux host
   }

   vi services.cfg

   define service{
           use                     generic-service
           host_name               Nagios_Centos_Client1
           service_description     CPU Load
           check_command           check_nrpe!check_load
           }
   
   define service{
           use                     generic-service
           host_name               Nagios_Centos_Client1
           service_description     Total Processes
           check_command           check_nrpe!check_total_procs
           }
   
   define service{
           use                     generic-service
           host_name               Nagios_Centos_Client1
           service_description     Current Users
           check_command           check_nrpe!check_users
           }
   
   define service{
           use                     generic-service
           host_name               Nagios_Centos_Client1
           service_description     Disk Monitoring
           check_command           check_nrpe!check_sda1
           }
   
   define service{
           use                     generic-service
           host_name               Nagios_Centos_Client1
           service_description     Zombie Monitoring
           check_command           check_nrpe!check_zombie_procs
           }

   修改nagios.cfg
   vi /etc/nagios/nagios.cfg 添加如下两行配置
   cfg_file=/etc/nagios/objects/services.cfg
   cfg_file=/etc/nagios/objects/hosts.cfg
   修改command.cfg
   vi /etc/nagios/objects/commamds.cfg 添加

   define command{
           command_name check_nrpe
           command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
           }

   检验nagios的配置是否正常
   cd /etc/nagios
   nagios -v nagios.cfg
   提示没有错误，重启nagios即可

8. 参考文档：http://www.tecmint.com/how-to-add-linux-host-to-nagios-monitoring-server/
   
9. 官方nrpe下载地址
   打开：http://sourceforge.net/projects/nagios/files/nrpe-2.x/
   wget http://liquidtelecom.dl.sourceforge.net/project/nagios/nrpe-2.x/nrpe-2.15/nrpe-2.15.tar.gz