1、NRPE介绍
NRPE是Nagios的一个功能扩展，它可在远程Linux/Unix主机上执行插件程序。通过在远程服务器上安装NRPE插件及Nagios插件程序来向Nagios监控平台提供该服务器的本地情况，如CPU负载，内存使用，磁盘使用等。这里将Nagios监控端称为Nagios服务器端，而将远程被监控的主机称为Nagios客户端。
Nagios监控远程主机的方法有多种，其方式包括SNMP，NRPE,SSH,NCSA等。这里介绍其通过NRPE监控远程Linux主机的方式。
NRPE（Nagios Remote Plugin Executor）是用于在远端服务器上运行监测命令的守护进程，它用于让Nagios监控端基于安装的方式触发远端主机上的检测命令，并将检测结果返回给监控端。而其执行的开销远低于基于SSH的检测方式，而且检测过程不需要远程主机上的系统账号信息，其安全性也高于SSH的检测方式。
2、NRPE的工作原理
NRPE有两部分组成
check_nrpe插件：位于监控主机上
nrpe daemon：运行在远程主机上，通常是被监控端agent
注意：nrpe daemon需要Nagios-plugins插件的支持，否则daemon不能做任何监控
当Nagios需要监控某个远程Linux主机的服务或者资源情况时：
首先：Nagios会运行check_nrpe这个插件，告诉它要检查什么；
其次：check_nrpe插件会连接到远程的NRPE daemon，所用的方式是SSL；
然后：NRPE daemon 会运行相应的Nagios插件来执行检查；
最后：NRPE daemon 将检查的结果返回给check_nrpe 插件，插件将其递交给nagios做处理。
原博客地址： http://blog.csdn.net/mchdba/article/details/46666229
原作者：黄杉 (mchdba)
3、被监控端安装Nagios-plugins插件和NRPE
去mysql客户端安装nrpe客户端服务
3.1、添加nagios用户
[root@localhost ~]# useradd -s/sbin/nologin nagios
3.2，安装nagios插件
[root@localhost ~]# yum -yinstall gcc gcc-c++ make openssl openssl-devel
3.3，安装nrpe
tar -xvf nrpe-2.15.tar.gz
cd nrpe-2.15
./configure--with-nrpe-user=nagios --with-nrpe-group=nagios --with-nagios-user=nagios--with-nagios-group=nagios --enable-command-args --enable-ssl
make all
make install-plugin
make install-daemon
make install-daemon-config
3.4，去检查nrpe配置
grep -v '^#' /usr/local/nagios/etc/nrpe.cfg |sed '/^$/d'
[root@localhost ~]# grep -v '^#' /usr/local/nagios/etc/nrpe.cfg|sed '/^$/d'
log_facility=daemon
pid_file=/var/run/nrpe.pid
server_port=5666
nrpe_user=nagios
nrpe_group=nagios
allowed_hosts=127.0.0.1,192.168.121.211
dont_blame_nrpe=0
allow_bash_command_substitution=0
debug=0
command_timeout=60
connection_timeout=300
command[check_users]=/usr/local/nagios/libexec/check_users-w 8 -c 12
command[check_load]=/usr/local/nagios/libexec/check_load -w15,10,5 -c 30,25,20
command[check_sda1]=/usr/local/nagios/libexec/check_disk -w20% -c 10% -p /dev/sda3
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 750 -c 800
command[check-host-alive]=/usr/local/nagios/libexec/check_ping-H 10.254.3.72 -w 3000.0,80% -c 5000.0,100% -p 5
command[check_mysql_status]=/usr/local/nagios/libexec/check_mysql-unagios -P3306 -s /usr/local/mysql/mysql.sock -Hlocalhost--password='nagiosq@0625' -d test -w 60 -c 100
[root@localhost ~]#
3.5，启动nrpe
/usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe
4，制作启动脚本：
[root@localhost bin]# cat /etc/init.d/nrped
#chkconfig: 2345 80 90
#description:auto_run
NRPE=/usr/local/nagios/bin/nrpe
NRPECONF=/usr/local/nagios/etc/nrpe.cfg
case "$1" in
start)
echo -n "Starting NRPE daemon..."
$NRPE -c $NRPECONF -d
echo " done."
;;
stop)
echo -n "Stopping NRPE daemon..."
pkill -u nagios nrpe
echo " done."
;;
restart)
$0 stop
sleep 2
$0 start
;;
*)
echo "Usage: $0 start|stop|restart"
;;
esac
exit 0
[root@localhost bin]#
5，设置启动
chmod +x /etc/init.d/nrped
chkconfig --add nrped
chkconfig nrped on
[root@localhost bin]# ps -eaf|grep nrpe
nagios 30440 1 0 23:48 ? 00:00:00 /usr/local/nagios/bin/nrpe -c/usr/local/nagios/etc/nrpe.cfg -d
root 30442 3292 0 23:48 pts/0 00:00:00 grep nrpe
[root@localhost bin]#
[root@localhost bin]# netstat -tnlp |grepnrpe
tcp 0 0 0.0.0.0:5666 0.0.0.0:* LISTEN 30440/nrpe
tcp 0 0 :::5666 :::* LISTEN 30440/nrpe
[root@localhost bin]#
6，监控端安装nrpe
tar xf nrpe-2.15.tar.gz
cd nrpe-2.15
./configure --with-nrpe-user=nagios --with-nrpe-group=nagios --with-nagios-user=nagios --with-nagios-group=nagios --enable-command-args --enable-ssl
make all
make install-plugin
#安装完成后，会在Nagios安装目录的libexec下生成check_nrpe的插件，如下所示：
[root@test_db2 nagios]# ll /usr/local/nagios/libexec/check_nrpe
-rwxrwxr-x 1 nagios nagios 76777 Jun 2523:53 /usr/local/nagios/libexec/check_nrpe
[root@test_db2 nagios]#
检测报错：
[root@test_db2 libexec]# ./check_nrpe -H192.168.121.210
CHECK_NRPE: Error - Could not complete SSLhandshake.
[root@test_db2 libexec]#
去客户端在allowed_hosts中添加监控端IP地址
[root@localhost ~]# vim/usr/local/nagios/etc/nrpe.cfg
allowed_hosts=127.0.0.1,192.168.121.211
在mysql服务器上，报错：
[root@localhost ~]#/usr/local/nagios/libexec/check_mysql -unagios -P3306 -S -s/usr/local/mysql/mysql.sock -Hlocalhost --password='nagiosq@0512' -d test -w 60-c 100
/usr/local/nagios/libexec/check_mysql:error while loading shared libraries: libmysqlclient.so.18: cannot open sharedobject file: No such file or directory
[root@localhost ~]#
[root@localhost ~]# find / -namelibmysqlclient.so.18
/usr/local/mysql/lib/libmysqlclient.so.18
/root/mysql/mysql-5.6.12/libmysql/libmysqlclient.so.18
/root/mysql-5.6.12/libmysql/libmysqlclient.so.18
[root@localhost ~]# ln -s/usr/local/mysql/lib/libmysqlclient.so.18 /usr/lib64/libmysqlclient.so.18
[root@localhost ~]#
添加mysql账号：
mysql> GRANT PROCESS, SUPER, REPLICATIONCLIENT ON *.* TO 'nagios'@'localhost' IDENTIFIED BY 'nagiosq@0625';
Query OK, 0 rows affected (0.05 sec)
mysql>
客户端自己检测：
[root@localhost ~]#/usr/local/nagios/libexec/check_mysql -unagios -P3306 -s /usr/local/mysql/mysql.sock -Hlocalhost--password='nagiosq@0625' -d test -w 60 -c 100
Uptime: 1823238 Threads: 6 Questions: 684495 Slow queries:0 Opens: 124 Flush tables: 1 Open tables: 116 Queries per second avg:0.375|Connections=3116c;;; Open_files=19;;; Open_tables=116;;; Qcache_free_memory=61538880;;;Qcache_hits=176271c;;; Qcache_inserts=41370c;;; Qcache_lowmem_prunes=0c;;;Qcache_not_cached=331835c;;; Qcache_queries_in_cache=3373;;; Queries=684496c;;;Questions=681384c;;; Table_locks_waited=0c;;; Threads_connected=5;;;Threads_running=2;;; Uptime=1823238c;;;
[root@localhost ~]#
7，完善配置文件
7.1在command.cfg里面添加监控command命令
将servers.cfg添加进nagios.cfg里面，将command.cfg里面的check_host_alive以及check_mysql_status补充好，然后重启nagios
# add by timman on 20150512
define command{
command_name check_mysql_status
command_line $USER1$/check_mysql_status-w $ARG1$ -c $ARG2$
}
# 'check_nrpe' command definition,add bytimman on 20140508
define command{
command_name check_nrpe
command_line $USER1$/check_nrpe-H $HOSTADDRESS$ -c $ARG1$
}
define command{
command_name check_host_alive
command_line $USER1$/check_ping-H $HOSTADDRESS$ -w 3000.0,80% -c 5000.0,100% -p 5
}
7.2在servers.cfg里面添加check_mysql_status、 check_host_alive等服务监控项。
[root@test_db2 etc]# more servers.cfg
# servicedefinition
define service{
host_name cactitest
service_description check_load
check_command check_nrpe!check_load
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
define service{
host_name cactitest
service_description check_host_alive
check_command check_host_alive
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
define service{
host_name cactitest
service_description Check Disksda1
check_command check_nrpe!check_sda1
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
define service{
host_name cactitest
service_description TotalProcesses
check_command check_nrpe!check_total_procs
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
define service{
host_name cactitest
service_description CurrentUsers
check_command check_nrpe!check_users
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
define service{
host_name cactitest
service_description CheckZombie Procs
check_command check_nrpe!check_zombie_procs
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
define service{
host_name cactitest
service_description CheckMysql Status
check_command check_nrpe!check_mysql_status
max_check_attempts 5
normal_check_interval 3
retry_check_interval 2
check_period 24x7
notification_interval 10
notification_period 24x7
notification_options w,u,c,r
contact_groups dba
}
7.3 在nagios.cfg加载servers.cfg等配置文件
在nagios.cfg里面配置
cfg_file=/usr/local/nagios/etc/servers.cfg
同时添加新的主机或者服务配置cfg文件，都需要在nagios.cfg里面配置一下，然后重启nagios才能生效，如下所示：
[root@test_db2 nagios]# grep -v '^#'/usr/local/nagios/etc/nagios.cfg |sed '/^$/d' |grep cfg_file
cfg_file=/usr/local/nagios/etc/objects/commands.cfg
cfg_file=/usr/local/nagios/etc/objects/contacts.cfg
cfg_file=/usr/local/nagios/etc/contactgroups.cfg
cfg_file=/usr/local/nagios/etc/objects/timeperiods.cfg
cfg_file=/usr/local/nagios/etc/objects/templates.cfg
cfg_file=/usr/local/nagios/etc/hosts.cfg
cfg_file=/usr/local/nagios/etc/servers.cfg
cfg_file=/usr/local/nagios/etc/hostgroups.cfg
cfg_file=/usr/local/nagios/etc/objects/localhost.cfg
[root@test_db2 nagios]#
8，之后在页面就可以看到监控效果了
