他のサーバーのリソース監視する方法

他のサーバーのリソース監視する方法

Modified: 28 May 2006

ネットワーク上の他のLinuxサーバーのリソース監視をするには、nrpe(Nagios Remote Plugin Executer)というリソース監視ツールを監視対象のサーバーにインストールする必要があります。

ここの解説を参考に実験しました。
http://anabuki.dip.jp/tips/nagios.htm

nrpeのダウンロードとインストール
リモートサーバーの設定
NAGIOSサーバー側の設定
動作チェックや確認

nrpeのダウンロードとインストール　

以下からダウンロードします。

http://www.nagiosexchange.org/NRPE.77.0.html?&tx_netnagext_pi1[p_view]=126

以下のように、解凍してMakeします。

# tar zxvf nrpe-2.0.tar.gz
# cd nrpe-2.0
# ./configure
# make all

OpenSSLのライブラリがない場合エラーになりますので、エラーになる場合は、インストールする必要があります。（２．０のとき）
# yum install openssl
# yum install openssl-devel
参考にしたページにも書いてありますが、実は、2.0 では、以下のエラーが出てうまくいかなかったので、1.9 で行いました。
CHECK_NRPE: Error - Could not complete SSL handshake
以下に回避方法の説明がありましたが。
http://www.nagios.org/faqs/viewfaq.php?faq_id=191

リモートサーバーの設定　

前もって、Pluginを、以下からダウンロードし、

http://www.nagios.org/download/

以下の手順でリモートサーバーにもインストールします。

# tar zxvf nagios-plugins-1.4.2.tar.gz
# cd nagios-plugins-1.4.2
# ./configure 
# make
# make install

次に、nrpeのモジュールをインストールします。

# cp src/nrpe /usr/local/nagios/libexec/
# cp nrpe.cfg /usr/local/nagios/etc/

設定ファイル（"/usr/local/nagios/etc/nrpe.cfg"）を以下のように変更します。

#############################################################################
# Sample NRPE Config File 
# Written by: Ethan Galstad (nagios@nagios.org)
# 
# Last Modified: 03-05-2003
#
# NOTES:
# This is a sample configuration file for the NRPE daemon.  It needs to be
# located on the remote host that is running the NRPE daemon, not the host
# from which the check_nrpe client is being executed.
#############################################################################



# PORT NUMBER
# Port number we should wait for connections on.
# NOTE: This must be a non-priviledged port (i.e. > 1024).
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

server_port=5666



# SERVER ADDRESS
# Address that nrpe should bind to in case there are more than one interface
# and you do not want nrpe to bind on all interfaces.
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

#server_address=192.168.1.1



# ALLOWED HOST ADDRESSES
# This is a comma-delimited list of IP address of hosts that are allowed
# to talk to the NRPE daemon.
#
# NOTE: The daemon only does rudimentary checking of the client's IP
#       address.  I would highly recommend adding entries in your
#       /etc/hosts.allow file to allow only the specified host to connect
#       to the port you are running this daemon on.
#
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

allowed_hosts=127.0.0.1



# NRPE USER
# This determines the effective user that the NRPE daemon should run as.  
# You can either supply a username or a UID.
# 
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

nrpe_user=nagios



# NRPE GROUP
# This determines the effective group that the NRPE daemon should run as.  
# You can either supply a group name or a GID.
# 
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

nrpe_group=nagios



# COMMAND ARGUMENT PROCESSING
# This option determines whether or not the NRPE daemon will allow clients
# to specify arguments to commands that are executed.  This option only works
# if the daemon was configured with the --enable-command-args configure script
# option.  
#
# *** ENABLING THIS OPTION IS A SECURITY RISK! *** 
# Read the SECURITY file for information on some of the security implications
# of enabling this variable.
#
# Values: 0=do not allow arguments, 1=allow command arguments

dont_blame_nrpe=0



# DEBUGGING OPTION
# This option determines whether or not debugging messages are logged to the
# syslog facility.
# Values: 0=debugging off, 1=debugging on

debug=0



# COMMAND TIMEOUT
# This specifies the maximum number of seconds that the NRPE daemon will
# allow plugins to finish executing before killing them off.

command_timeout=60



# INCLUDE CONFIG FILE
# This directive allows you to include definitions from an external config file.

#include=<somefile.cfg>



# INCLUDE CONFIG DIRECTORY
# This directive allows you to include definitions from config files (with a
# .cfg extension) in one or more directories (with recursion).

#include_dir=<somedirectory>
#include_dir=<someotherdirectory>



# COMMAND DEFINITIONS
# Command definitions that this daemon will run.  Definitions
# are in the following format:
#
# command[<command_name>]=<command_line>
#
# When the daemon receives a request to return the results of <command_name>
# it will execute the command specified by the <command_line> argument.
#
# Unlike Nagios, the command line cannot contain macros - it must be
# typed exactly as it should be executed.
#
# Note: Any plugins that are used in the command lines must reside
# on the machine that this daemon is running on!  The examples below
# assume that you have plugins installed in a /usr/local/nagios/libexec
# directory.  Also note that you will have to modify the definitions below
# to match the argument format the plugins expect.  Remember, these are
# examples only!

# The following examples use hardcoded command arguments...

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_disk1]=/usr/local/nagios/libexec/check_disk -w 20 -c 10 -p /dev/sda1
command[check_disk2]=/usr/local/nagios/libexec/check_disk -w 20 -c 10 -p /dev/sda2
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 

# The following examples allow user-supplied arguments and can
# only be used if the NRPE daemon was compiled with support for 
# command arguments *AND* the dont_blame_nrpe directive in this
# config file is set to '1'...

#command[check_users]=/usr/local/nagios/libexec/check_users -w $ARG1$ -c $ARG2$
#command[check_load]=/usr/local/nagios/libexec/check_load -w $ARG1$ -c $ARG2$
#command[check_disk]=/usr/local/nagios/libexec/check_disk -w $ARG1$ -c $ARG2$ -p $ARG3$
#command[check_procs]=/usr/local/nagios/libexec/check_procs -w $ARG1$ -c $ARG2$ -s $ARG3$
#

実行ユーザを作ります。

# useradd -d /usr/local/nagios nagios

"/etc/services"に以下を追加します。

nrpe            5666/TCP                        # NRPE

"/etc/xinetd.d/nrpe"を作成します。

service nrpe
{
        flags 			= REUSE
        log_on_failure 	+= USERID
        port 				= 5666
        socket_type 		= stream
        protocol 			= tcp
        user 				= nagios
        server 			= /usr/local/nagios/libexec/nrpe
        server_args 		= -c /usr/local/nagios/etc/nrpe.cfg --inetd
        type 				= UNLISTED
        wait 				= no
}

"xinetd"を再起動します。

# service xinetd restart

NAGIOSサーバー側の設定　

チェックコマンド（プラグイン）をコピー（インストール）します。
# cp src/check_nrpe  /usr/local/nagios/libexec/ 
"/etc/services"に以下を追加します。
nrpe            5666/TCP                        # NRPE
"/usr/local/nagios/etc/checkcommands.cfg"に、以下を追加します。
# 'check_nrpe' command definition
define command{
        command_name    check_nrpe
        command_line    $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
        }
"/usr/local/nagios/etc/services.cfg"に、以下を追加します。
### Resource monitor ###
define service{
        use                     generic-service1
        host_name               recipebase
        service_description     HDD
        check_command           check_nrpe!check_disk1
        }
nagiosを再起動します。
# service nagios restart

動作チェックや確認　

リモート側の動作確認

"/usr/local/nagios/etc/nrpe.cfg"で設定したチェックコマンドの実行を確認します。

# /usr/local/nagios/libexec/check_users -w 5 -c 10
USERS OK - 1 users currently logged in |users=1;5;10;0
# /usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
OK - load average: 0.04, 0.02, 0.00|load1=0.040;15.000;30.000;0; load5=0.020;10.000;25.000;0; load15=0.000;5.000;20.000;0; 
# /usr/local/nagios/libexec/check_disk -w 20 -c 10 -p /dev/sda1
DISK OK - free space: /boot 58 MB (59%);| /boot=40MB;78;88;0;98
# /usr/local/nagios/libexec/check_disk -w 20 -c 10 -p /dev/sda2
DISK OK - free space: / 722 MB (21%);| /=2707MB;3408;3418;0;3428
# /usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z
PROCS OK: 0 processes with STATE = Z
# /usr/local/nagios/libexec/check_procs -w 150 -c 200
PROCS OK: 72 processes
#

ポートが開いていることを確認します。

# netstat -ln
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State      
tcp        0      0 0.0.0.0:2049                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:5666                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:901                 0.0.0.0:*                   LISTEN
　　　　：
#

エラーが出る場合
データがうまく取得できない場合、以下のエラー表示になります。

CHECK_NRPE: Error receiving data from host.

"/usr/local/nagios/etc/nrpe.cfg"を開いて、"debug=1"にして、"tail /var/log/messages"を確認します。

私の場合、以下のようなエラーが出たりしました。

Jan  8 00:55:32 host nrpe[18690]: Unable to open config file '/usr/local/nagios/etc/nrpe.cfg' for reading 
Jan  8 00:55:32 host nrpe[18690]: Config file '/usr/local/nagios/etc/nrpe.cfg' contained errors, bailing out...

Jan  8 01:00:34 host nrpe[18755]: No variable value specified in config file '/usr/local/nagios/etc/nrpe.cfg' - Line 110 
Jan  8 01:00:34 host nrpe[18755]: Config file '/usr/local/nagios/etc/nrpe.cfg' contained errors, bailing out...