Nagios利用NRPE监控Linux主机
一、简介
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
详细的介绍NRPE的工作原理
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。
二、被监控端安装Nagios-plugins插件和NRPE
1、添加nagios用户
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[[email protected] ~] # useradd -s /sbin/nologin nagios
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2、安装nagios-plugins,因为NRPE依赖此插件
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[[email protected] ~] # yum -y install gcc gcc-c++ make openssl openssl-devel
[[email protected] ~] # tar xf nagios-plugins-2.0.3.tar.gz
[[email protected] ~] # cd nagios-plugins-2.0.3
[[email protected] nagios-plugins-2.0.3] # ./configure --with-nagios-user=nagios --with-nagios-group=nagios
[[email protected] nagios-plugins-2.0.3] # make && make install
#注意:如何要监控mysql 需要添加 --with-mysql |
3、安装NRPE
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[[email protected] ~] # tar xf nrpe-2.15.tar.gz
[[email protected] ~] # cd nrpe-2.15
[[email protected] 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
[[email protected] nrpe-2.15] # make all
[[email protected] nrpe-2.15] # make install-plugin
[[email protected] nrpe-2.15] # make install-daemon
[[email protected] nrpe-2.15] # make install-daemon-config
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4、配置NRPE
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[[email protected] ~] # grep -v '^#' /usr/local/nagios/etc/nrpe.cfg |sed '/^$/d'
log_facility=daemon pid_file= /var/run/nrpe .pid
server_port=5666 #监听的端口
nrpe_user=nagios nrpe_group=nagios allowed_hosts=192.168.0.105 #允许的地址通常是Nagios服务器端
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 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
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5、启动NRPE
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#以守护进程的方式启动 [[email protected] ~] # /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d
[[email protected] ~] # netstat -tulpn | grep nrpe
tcp 0 0 0.0.0.0:5666 0.0.0.0:* LISTEN 22597 /nrpe tcp 0 0 :::5666 :::* LISTEN 22597 /nrpe
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有两种方式用于管理nrpe服务,nrpe有两种运行模式:
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-i # Run as a service under inetd or xinetd
-d # Run as a standalone daemon
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可以为nrpe编写启动脚本,使得nrpe以standard alone方式运行:
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[[email protected] ~] # cat /etc/init.d/nrped
#!/bin/bash # chkconfig: 2345 88 12 # description: NRPE DAEMON 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
[[email protected] ~] # chmod +x /etc/init.d/nrped
[[email protected] ~] # chkconfig --add nrped
[[email protected] ~] # chkconfig nrped on
[[email protected] ~] # service nrped start
Starting NRPE daemon... done .
[[email protected] ~] # netstat -tnlp
Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID /Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1031 /sshd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1108 /master tcp 0 0 0.0.0.0:5666 0.0.0.0:* LISTEN 22597 /nrpe tcp 0 0 :::22 :::* LISTEN 1031 /sshd tcp 0 0 ::1:25 :::* LISTEN 1108 /master tcp 0 0 :::5666 :::* LISTEN 22597 /nrpe
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三、监控端安装NRPE
1、安装NRPE
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[[email protected] ~] # tar xf nrpe-2.15.tar.gz
[[email protected] ~] # cd nrpe-2.15
[[email protected] 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
[[email protected] nrpe-2.15] # make all
[[email protected] nrpe-2.15] # 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 [[email protected] ~] # cd /usr/local/nagios/libexec/
[[email protected] libexec] # ll -d check_nrpe
-rwxrwxr-x. 1 nagios nagios 76769 9月 28 08:07 check_nrpe |
2、check_nrpe的用法
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[[email protected] libexec] # ./check_nrpe -h
NRPE Plugin for Nagios
Copyright (c) 1999-2008 Ethan Galstad ([email protected]) Version: 2.15 Last Modified: 09-06-2013 License: GPL v2 with exemptions (-l for more info)
SSL /TLS Available: Anonymous DH Mode, OpenSSL 0.9.6 or higher required
Usage: check_nrpe -H <host> [ -b <bindaddr> ] [-4] [-6] [-n] [-u] [-p <port>] [-t <timeout>] [-c < command >] [-a <arglist...>]
Options: -n = Do no use SSL
-u = Make socket timeouts return an UNKNOWN state instead of CRITICAL
<host> = The address of the host running the NRPE daemon
<bindaddr> = bind to local address
-4 = user ipv4 only
-6 = user ipv6 only
[port] = The port on which the daemon is running (default=5666)
[timeout] = Number of seconds before connection times out (default=10)
[ command ] = The name of the command that the remote daemon should run
[arglist] = Optional arguments that should be passed to the command . Multiple
arguments should be separated by a space. If provided, this must be
the last option supplied on the command line.
Note: This plugin requires that you have the NRPE daemon running on the remote host. You must also have configured the daemon to associate a specific plugin command
with the [ command ] option you are specifying here. Upon receipt of the
[ command ] argument, the NRPE daemon will run the appropriate plugin command and
send the plugin output and return code back to *this* plugin. This allows you
to execute plugins on remote hosts and 'fake' the results to make Nagios think
the plugin is being run locally. |
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通过NRPE监控远程Linux主机要使用chech_nrpe插件进行,其语法格式如下: check_nrpe -H <host> [-n] [-u] [-p <port>] [-t <timeout>] [-c < command >] [-a <arglist...>]
[[email protected] libexec] # ./check_nrpe -H 192.168.0.81
NRPE v2.15 |
3、定义命令
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[[email protected] ~] # cd /usr/local/nagios/etc/objects/
[[email protected] objects] # vim commands.cfg
#增加到末尾行 define command {
command_name check_nrpe
command_line $USER1$ /check_nrpe -H "$HOSTADDRESS$" -c "$ARG1$"
} |
4、定义服务
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[[email protected] objects] # cp windows.cfg linhost.cfg
[[email protected] objects] # grep -v '^#' linhost.cfg |sed '/^$/d'
define host{ use linux-server
host_name linhost
alias My Linux Server
address 192.168.0.81
}
define service{ use generic-service
host_name linhost
service_description CHECK USER
check_command check_nrpe!check_users
}
define service{ use generic-service
host_name linhost
service_description Load
check_command check_nrpe!check_load
}
define service{ use generic-service
host_name linhost
service_description SDA1
check_command check_nrpe!check_hda1
}
define service{ use generic-service
host_name linhost
service_description Zombie
check_command check_nrpe!check_zombie_procs
}
define service{ use generic-service
host_name linhost
service_description Total procs
check_command check_nrpe!check_total_procs
}
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这里重点说下,Nagios服务端定义服务的命令完全是根据被监控端NRPE中内置的监控命令,如下图所示
5、启动所定义的命令和服务
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[[email protected] ~] # vim /usr/local/nagios/etc/nagios.cfg
#增加一行 cfg_file= /usr/local/nagios/etc/objects/linhost .cfg
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6、配置文件语法检查
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[[email protected] ~] # service nagios configtest
Nagios Core 4.0.7 Copyright (c) 2009-present Nagios Core Development Team and Community Contributors Copyright (c) 1999-2009 Ethan Galstad Last Modified: 06-03-2014 License: GPL Website: http: //www .nagios.org
Reading configuration data... Read main config file okay...
Read object config files okay...
Running pre-flight check on configuration data... Checking objects... Checked 20 services.
Checked 3 hosts.
Checked 2 host groups .
Checked 0 service groups .
Checked 1 contacts.
Checked 1 contact groups .
Checked 26 commands.
Checked 5 time periods.
Checked 0 host escalations.
Checked 0 service escalations.
Checking for circular paths...
Checked 3 hosts
Checked 0 service dependencies
Checked 0 host dependencies
Checked 5 timeperiods
Checking global event handlers... Checking obsessive compulsive processor commands... Checking misc settings... Total Warnings: 0 Total Errors: 0 Things look okay - No serious problems were detected during the pre-flight check
Object precache file created:
/usr/local/nagios/var/objects .precache
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7、重新启动nagios服务
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[[email protected] ~] # service nagios restart
Running configuration check... Stopping nagios: done .
Starting nagios: done .
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8、打开Nagios web监控页面
1)首先点击【Hosts】查看监控主机状态是否为UP
2)其次点击【Services】查看各监控服务的状态是否为OK
注意:在监控新添加的主机linhost;出现状态为CRITICAL,提示没有那个文件或目录。下面是解决办法
在监控Linhost主机时出现一个CRITICAL的警告,查找解决办法
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###被监控端修改NRPE配置文件并重启NRPE服务 [[email protected] etc] # vim nrpe.cfg
command [check_sda1]= /usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/sda1
[[email protected] etc] # service nrped restart
###监控端修改linhost.cfg配置文件并重启nagios和httpd服务 [[email protected] objects] # vim linhost.cfg
#注释:原来这里是hda1,现在修改成sda1 define service{ use generic-service
host_name linhost
service_description SDA1
check_command check_nrpe!check_sda1
}
[[email protected] ~] # service nagios restart
Running configuration check... Stopping nagios: done .
Starting nagios: done .
[[email protected] ~] # service httpd restart
停止 httpd: [确定] 正在启动 httpd: [确定] |
再次点击【services】即为刷新页面,查看如下图所示:
时间:2014-12-26
更新一个监控httpd服务的错误
今天在看日志的时候,在nginx的错误日志中发现很多一样的错误日志,起初是因为其它php程序的bug呢,后来跟开发人员讨论,排除了这个问题,于是就到Google上搜索,才知道原来是监控上配置文件的问题?
错误日志截图:
http://forum.joomla.org/viewtopic.php?t=666220
本文转自zys467754239 51CTO博客,原文链接:http://blog.51cto.com/467754239/1558897,如需转载请自行联系原作者