Difference between revisions of "How to Setup and configure Nagios"

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::::::::: <u>'''Version 0.6'''</u>
+
::::::::: <u>'''Version 0.7'''</u>
  
  
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== 2.0 Server Installation (using tarball) ==
 
== 2.0 Server Installation (using tarball) ==
 
  
 
This guide will provide you with instructions on how to install Nagios from source (code) on Fedora 13 and have it monitoring your local and client machines.
 
This guide will provide you with instructions on how to install Nagios from source (code) on Fedora 13 and have it monitoring your local and client machines.
Line 47: Line 46:
  
 
* Monitor Nagios clients
 
* Monitor Nagios clients
 
  
 
'''2.2 Prerequisites'''
 
'''2.2 Prerequisites'''
Line 104: Line 102:
  
 
<code>wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.15.tar.gz  </code>
 
<code>wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.15.tar.gz  </code>
 
  
 
'''2.5 Compile and Install Nagios'''
 
'''2.5 Compile and Install Nagios'''
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4. Install binaries, init script, sample config files and set permissions on the external command directory.
 
4. Install binaries, init script, sample config files and set permissions on the external command directory.
  
<pre>Note: you have to be root to issue the following commands.</pre>
+
<pre>Note: You have to be root to issue the following commands.</pre>
  
 
<code>make install </code>
 
<code>make install </code>
Line 137: Line 134:
  
 
<pre>Note: DO NOT start Nagios yet</pre>
 
<pre>Note: DO NOT start Nagios yet</pre>
 
  
 
'''2.6 Customize Configuration'''
 
'''2.6 Customize Configuration'''
Line 145: Line 141:
 
<code>vi /usr/local/nagios/etc/objects/contacts.cfg </code>
 
<code>vi /usr/local/nagios/etc/objects/contacts.cfg </code>
  
<pre>Note: this will be changed to Chris Tyler’s email.</pre>
+
<pre>
 +
define contact{
  
 +
  contact_name    nagiosadmin                ; Short name of user
 +
 +
  use            generic-contact            ; Inherit default values from generic-contact template(defined above)
 +
 +
  alias          Nagios Admin                ; Full name of user
 +
 +
  email          email@learn.senecac.on.ca  ; *****CHANGE THIS TO YOUR EMAIL ADDRESS *****
 +
 +
        }
 +
</pre>
  
 
'''2.7 Configure the Web Interface'''
 
'''2.7 Configure the Web Interface'''
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3. Restart Apache to make the new settings take effect.
 
3. Restart Apache to make the new settings take effect.
 +
 
<code>service httpd restart</code>
 
<code>service httpd restart</code>
 
  
 
'''2.8 Compile and Install the Nagios Plugins'''
 
'''2.8 Compile and Install the Nagios Plugins'''
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<code>make install</code>
 
<code>make install</code>
 
  
 
'''2.9 Start Nagios'''
 
'''2.9 Start Nagios'''
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3. If there are no errors, start Nagios. If you got errors, please check nagios.cfg file in step 2, and try it again.
 
3. If there are no errors, start Nagios. If you got errors, please check nagios.cfg file in step 2, and try it again.
 +
 
<code>service nagios start  </code>
 
<code>service nagios start  </code>
 
  
 
'''2.10 Modify SELinux Settings'''
 
'''2.10 Modify SELinux Settings'''
Line 228: Line 234:
  
 
<code>chcon -R -t httpd_sys_content_t /usr/local/nagios/share/  </code>
 
<code>chcon -R -t httpd_sys_content_t /usr/local/nagios/share/  </code>
 
  
 
'''2.11 Login to the Web Interface'''
 
'''2.11 Login to the Web Interface'''
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Click on the "Service Detail" navigational bar link to see details of what's being monitored on your local machine. It will take a few minutes for Nagios to check all the services associated with your machine, as the checks are spread out over time.
 
Click on the "Service Detail" navigational bar link to see details of what's being monitored on your local machine. It will take a few minutes for Nagios to check all the services associated with your machine, as the checks are spread out over time.
 
  
 
'''2.12 Open Port 5666 on Firewall'''
 
'''2.12 Open Port 5666 on Firewall'''
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<code>service iptables save</code>
 
<code>service iptables save</code>
 
  
 
'''2.13 You're Done'''
 
'''2.13 You're Done'''
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1. Create a Nagios_NRPE folder.
 
1. Create a Nagios_NRPE folder.
 
  
 
<code>mkdir -p ~/Nagios/Nagios_NRPE</code>
 
<code>mkdir -p ~/Nagios/Nagios_NRPE</code>
Line 310: Line 312:
 
2. Add the following at the end of the file:
 
2. Add the following at the end of the file:
  
<pre>define command{         
+
<pre>
 +
define command{         
  
command_name check_nrpe         
+
              command_name check_nrpe         
  
command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
+
              command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
  
 
         }
 
         }
Line 328: Line 331:
  
 
<code>vi /usr/local/nagios/etc/objects/linux-box-remote.cfg</code>
 
<code>vi /usr/local/nagios/etc/objects/linux-box-remote.cfg</code>
 
  
 
<pre>Note: Information below is just an example of the template file.</pre>
 
<pre>Note: Information below is just an example of the template file.</pre>
Line 345: Line 347:
 
           notification_options  d,r
 
           notification_options  d,r
 
           contact_groups        admins
 
           contact_groups        admins
           register              0     ; DONT REGISTER THIS - ITS A TEMPLATE
+
           register              0                     ; DO NOT REGISTER THIS - ITS A TEMPLATE
 
           }
 
           }
  
 
define host{
 
define host{
           use       linux-box-remote    ; Inherit default values from a template
+
           use         linux-box-remote    ; Inherit default values from a template
           host_name Centos5   ; The name we're giving to this server
+
           host_name   Centos5             ; The name we're giving to this server
           alias     Centos5 ; A longer name for the server
+
           alias       Centos5             ; A longer name for the server
           address   142.204.133.90   ; IP address of the server
+
           address     142.204.133.90       ; IP address of the server
 
           }
 
           }
  
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<code>service nagios restart</code>
 
<code>service nagios restart</code>
 
  
 
== 4.0 Server Installation (using yum utility)==
 
== 4.0 Server Installation (using yum utility)==
Line 422: Line 423:
 
Make sure you've installed the following packages on your Fedora 13 installation before continuing.
 
Make sure you've installed the following packages on your Fedora 13 installation before continuing.
  
<pre>Note: you have to be root to install the following packages.</pre>
+
<pre>Note: You have to be root to install the following packages.</pre>
  
 
1. Install the following packages using yum install utility.
 
1. Install the following packages using yum install utility.
Line 434: Line 435:
 
<code>yum -y install nrpe </code>
 
<code>yum -y install nrpe </code>
  
 
 
'''4.2 Create Account Information'''
 
'''4.2 Create Account Information'''
  
1. While you still have root privilages from a previous step, create a new nagios user account and give it a password.
+
1. While you still have root privileges from a previous step, create a new nagios user account and give it a password.
  
 
<code>useradd -m nagios </code>
 
<code>useradd -m nagios </code>
Line 450: Line 450:
  
 
<code>usermod -a -G nagcmd apache </code>
 
<code>usermod -a -G nagcmd apache </code>
 
 
   
 
   
 
'''4.3 Configure the Web Interface'''
 
'''4.3 Configure the Web Interface'''
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1. Create a nagiosadmin account for logging into the Nagios web interface.
 
1. Create a nagiosadmin account for logging into the Nagios web interface.
  
<code>htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin </code>
+
<code>htpasswd -c /etc/nagios/htpasswd.users nagiosadmin </code>
  
 
Type the password: (your password is here)
 
Type the password: (your password is here)
  
 
<pre>Note: When you have installed all the required plugins,  using the “yum” utility, you will have to exhibit due diligence by
 
<pre>Note: When you have installed all the required plugins,  using the “yum” utility, you will have to exhibit due diligence by
ensuring that  the “ check_nrpe” plugin and check_nagios plugin is located in the /usr/lib64/nagios/plugins directory. If the  
+
ensuring that  the “check_nrpe” plugin and check_nagios plugin are located in the /usr/lib64/nagios/plugins directory. If the  
check_nrpe plugin is not present you will have either copy it from a compatible machine that holds it on the its system, or try  
+
check_nrpe plugin is not present you will have to either copy it from a compatible machine that already contains the appropriate
uninstalling the previous installation of the nagios plugins and proceed to re-installing the plugins again, using yum install. </pre>
+
or required plugin(s),or try uninstalling the previous installation of the nagios plugins and proceed to re-installing the plugins,
 +
using yum install. </pre>
  
Here is view of what your configuration files should like, in order to have successfully installed and configured version of Nagios.  The following lines were either added or modified for the nagios.cfg file on the monitoring host.
+
'''4.4 Nagios Configuration File'''
  
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Need add the info !!!!!!!!!!!!!!!!!!!!!!
+
<pre>
 
+
Note: Here is view of what your configuration files should look like, in order to have successfully installed and configured version of
'''4.4 Nagios Configuration File'''
+
Nagios. The following lines were either added or modified for the nagios.cfg file on the Nagios monitoring host.
 +
</pre>
  
 
1. Open nagios.cfg and edit it with your favourite editor.
 
1. Open nagios.cfg and edit it with your favourite editor.
Line 478: Line 479:
 
#Definitions for monitoring the local (Linux) host
 
#Definitions for monitoring the local (Linux) host
  
<code>cfg_file=/etc/nagios/objects/localhost.cfg</code>
+
  cfg_file=/etc/nagios/objects/localhost.cfg
  
 
#Definitions for monitoring a Remote (Linux) machine
 
#Definitions for monitoring a Remote (Linux) machine
  
<code>cfg_file=/etc/nagios/objects/linux-remote.cfg</code>
+
  cfg_file=/etc/nagios/objects/linux-remote.cfg
  
 
#Definitions for monitoring second Remote (Linux) machine
 
#Definitions for monitoring second Remote (Linux) machine
  
<code>cfg_file=/etc/nagios/objects/linux-romania.cfg</code>
+
  cfg_file=/etc/nagios/objects/linux-romania.cfg
  
 
</pre>
 
</pre>
Line 498: Line 499:
 
</pre>
 
</pre>
 
   
 
   
<code>#Allowed_hosts=127.0.0.1</code> is typically altered on the Remote host ONLY changes in IP address that allows a host to access the nrpe daemon system depends on an entities/organizations network requirements.
+
<code>#Allowed_hosts=127.0.0.1</code> is typically altered on the Remote host ONLY changes in IP address that allows a host to access the nrpe daemon system depends on an entity/organizations network requirements.
  
 
<pre>
 
<pre>
Line 508: Line 509:
 
<code>command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20</code>
 
<code>command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20</code>
  
<code>command[check_hda1]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /dev/$</code>
+
<code>command[check_hda1]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /dev/hda1</code>
  
<code>command[check_zombie_procs]=/usr/lib64/nagios/plugins/check_procs -w 5 -c 10 -s$</code>
+
<code>command[check_zombie_procs]=/usr/lib64/nagios/plugins/check_procs -w 5 -c 10 -s Z</code>
  
 
<code>command[check_total_procs]=/usr/lib64/nagios/plugins/check_procs -w 700 -c 900</code>
 
<code>command[check_total_procs]=/usr/lib64/nagios/plugins/check_procs -w 700 -c 900</code>
  
<pre>Note: If you're running the NRPE daemon as a standalone daemon you'll need to restart it. If you're running it under the  
+
<pre>Note: If you're running the NRPE daemon as a standalone daemon you'll need to restart it (using the command service nrpe restart). </pre>
inetd/xinetd superserver you don't need to do anything more.</pre>
 
  
 
'''4.5 Create a command definition'''
 
'''4.5 Create a command definition'''
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check_nrpe plugin. Open the sample commands.cfg file for editing...</pre>
 
check_nrpe plugin. Open the sample commands.cfg file for editing...</pre>
  
<code>vi /usr/local/nagios/etc/commands.cfg</code>
+
<code>vi /etc/nagios/objects/commands.cfg</code>
  
 
and add the following definition to the file:
 
and add the following definition to the file:
Line 528: Line 528:
 
<code>define command{</code>
 
<code>define command{</code>
  
<code>       command_name    check_nrpe</code>
+
<code>               command_name    check_nrpe</code>
  
<code>       command_line /usr/lib64/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -c $ARG1$</code>
+
<code>               command_line /usr/lib64/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -c $ARG1$</code>
  
 
<code>}</code>
 
<code>}</code>
Line 536: Line 536:
 
You are now ready to start adding services that should be monitored on the remote machine to the Nagios configuration...
 
You are now ready to start adding services that should be monitored on the remote machine to the Nagios configuration...
  
'''4.6 Edit localhost.cfg file'''
+
'''4.6 Edit the localhost.cfg file located in the /etc/nagios/objects directory'''
  
<pre>Note: The localhost .cfg file can be created from one of the templates.cfg files located in the /etc/nagios/objects  
+
<pre>Note: The localhost.cfg file can be created from one of the templates.cfg files located in the /etc/nagios/objects  
 
directory, here is a  brief view of how your localhost.cfg file should appear</pre>
 
directory, here is a  brief view of how your localhost.cfg file should appear</pre>
  
Line 546: Line 546:
 
define host{
 
define host{
  
      use                    linux-server    ; Name of host template$
+
            use                    linux-server    ; Name of host template$
  
                                              ; This host definition $
+
                                                    ; This host definition $
  
                                              ; in (or inherited by) $
+
                                                    ; in (or inherited by) $
  
        host_name              localhost
+
            host_name              localhost
  
        alias                  chile  #Example machine in this scenario
+
            alias                  chile  #Example machine in this scenario
  
        check_interval          5
+
            check_interval          5
  
        retry_interval          1
+
            retry_interval          1
  
        max_check_attempts   10
+
            max_check_attempts     10
  
        check_command          check-host-alive
+
            check_command          check-host-alive
  
        notification_period    24x7
+
            notification_period    24x7
  
        notification_interval  24x7
+
            notification_interval  24x7
  
        notification_options    d,r
+
            notification_options    d,r
  
        contact_groups          admins
+
            contact_groups          admins
  
        address                127.0.0.1
+
            address                127.0.0.1
  
 
}
 
}
Line 581: Line 581:
 
1. Edit contacts.cfg file is pretty straight forward and easy to decipher.
 
1. Edit contacts.cfg file is pretty straight forward and easy to decipher.
  
<code>vi /usr/local/nagios/etc/objects/contacts.cfg</code>
+
<code>vi /etc/nagios/objects/contacts.cfg</code>
  
 
<pre>
 
<pre>
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define contact{
 
define contact{
  
  contact_name    nagiosadmin ; Short name of user
+
              contact_name    nagiosadmin                 ; Short name of user
  
  use generic-contact   ; Inherit default values from generic-contact template(defined above)
+
              use             generic-contact             ; Inherit default values from generic-contact template(defined above)
  
  alias     Nagios Admin           ; Full name of user
+
              alias           Nagios Admin                 ; Full name of user
  
  email     email@learn.senecac.on.ca     ; ß CHANGE THIS TO YOUR EMAIL ADDRESS ******
+
              email           email@learn.senecac.on.ca   ; ß CHANGE THIS TO YOUR EMAIL ADDRESS ******
  
 
         }
 
         }
Line 609: Line 609:
 
<pre>Note: ScriptAlias directory path will differ based on what version of OS (Operating System) you are running on your machine.</pre>
 
<pre>Note: ScriptAlias directory path will differ based on what version of OS (Operating System) you are running on your machine.</pre>
  
1. Edit nagios.cfg file.
+
1. Edit nagios.cfg file located in apache (httpd) config files directory.
  
 
<code>vi /etc/httpd/conf.d/nagios.cfg </code>
 
<code>vi /etc/httpd/conf.d/nagios.cfg </code>
  
 
<pre>Note: The current machine has Fedora 13, however, for a machine running Fedora 12 it may differ eg. ScriptAlias /nagios
 
<pre>Note: The current machine has Fedora 13, however, for a machine running Fedora 12 it may differ eg. ScriptAlias /nagios
/cgi-bin “/usr/lib64/nagios/cgi-bin/”
+
/cgi-bin “/usr/lib64/nagios/cgi-bin/” It's important that these directory paths exist and contain the appropriate content.
 
 
It's important that these directory paths exist and contain the appropriate content.
 
 
</pre>
 
</pre>
 
   
 
   
Line 680: Line 678:
 
<code></Directory></code>
 
<code></Directory></code>
  
'''4.9 Installation On Arm 4-1'''
+
'''4.9 Note: This section highlights a brief snippet of two critical detailed steps REQUIRED for the installation and successful configuration of a Remote host (on an ARM machine) Cdot-guru-4-1 (Utilize the installation steps (5.0) that follow this section).'''
  
<pre>Note: nrpe daemon/ nrpe addon & required plugins</pre>
+
<pre>Using the 'yum utility' install the nrpe daemon/ nrpe addon & required plugins</pre>
  
 
The nrpe.d directory is located in /etc/nagios/nrpe.d
 
The nrpe.d directory is located in /etc/nagios/nrpe.d
Line 694: Line 692:
 
<code>vi /etc/nagios/nrpe.cfg</code>
 
<code>vi /etc/nagios/nrpe.cfg</code>
  
<code>allowed_hosts=<IP Address to that of the monitoring hosts> </code>
+
Note: Hong Kong has two NICs so the allowed_hosts entry would be entered twice with the two corressponding IPs for both NICs
 +
 
 +
<code>allowed_hosts=<Both the External & Internal IP Address for the monitoring hosts> </code>
  
 
comment out the line:
 
comment out the line:
Line 706: Line 706:
 
== 5.0 Setting up the Remote Host (using yum utility) ==
 
== 5.0 Setting up the Remote Host (using yum utility) ==
  
<pre>Note: This part will show how to setup the remote hosst with the nrpe daemon/nrpe addon & required plugins.</pre>
+
<pre>Note: This section will show how to setup the remote host with the nrpe daemon/nrpe addon & required plugins.</pre>
  
 
1. To install the nrpe daemon and nagios plugins run the following commands.
 
1. To install the nrpe daemon and nagios plugins run the following commands.
Line 718: Line 718:
 
<code>vi /etc/nagios/nrpe.cfg</code>
 
<code>vi /etc/nagios/nrpe.cfg</code>
  
Add an allowed_hosts  IP Address to nrpe.cfg file  eg. 142.204.133.123 (chile’s IP Address):
+
Add an allowed_hosts  IP Address to nrpe.cfg file  eg. 142.204.133.123 (chile’s IP Address), but for future configurations Hong Kong's IP Address will be used:
  
 
<code> Allowed_hosts=142.204.133.123 </code>
 
<code> Allowed_hosts=142.204.133.123 </code>
Line 731: Line 731:
 
</pre>
 
</pre>
  
4. Add a firewall rule to the INPUT chain  
+
4. Add a firewall rule to the INPUT chain - CAVEAT: The ARM machines do not utilize iptables, so the line below may not be required.
  
 
<code>iptables -I INPUT -p tcp -m tcp --dport 5666 -j ACCEPT</code>
 
<code>iptables -I INPUT -p tcp -m tcp --dport 5666 -j ACCEPT</code>
Line 773: Line 773:
  
 
<code>/usr/local/nagios/libexec/check_nrpe -H localhost -c check_zombie_procs</code>
 
<code>/usr/local/nagios/libexec/check_nrpe -H localhost -c check_zombie_procs</code>
 +
 +
8. At this point your installation and configuration of both the Nagios monitoring host and Remote host should be completed successfully. First ensure that your apache server and nagios is running on the corresponding monitoring host. To achieve a Frontend (GUI) view of Nagios functionality, go to your browser address field and type in the url-> http://<ip address of monitoring host goes here>/nagios. At the authentication prompt enter the username and password you set during the installation process.
 +
 +
== 5.1 Additional Details ==
 +
 +
<pre>This section will discuss some additional initiatives that were implemented on the Nagios Remote host. Due to the inability to obtain
 +
a plugin that is capable of monitoring mounted devices (on ARM machines) upon boot. A supplemental perl script was identified and
 +
utilize for this purpose. The check_mounted_disks script was conveniently added to /etc/init.d directory, and a few symlinks
 +
(soft links)were linked to appropriate runlevels on the ARM system. Once the system is rebooted the aforementioned script will
 +
execute automatically and perform a verification check of all devices that should be mounted on boot.</pre>
 +
 +
1. Symlinks were created using the command syntax.
 +
 +
<code>
 +
ln -s /etc/init.d/check_mounted_disks /etc/rc/rc2.d/S50check_mounted_disks
 +
     
 +
ln -s /etc/init.d/check_mounted_disks /etc/rc/rc2.d/K50check_mounted_disks</code>
 +
 +
2. When the check_mounted_disks script is executed on the command line, the following results are exhibited on the display monitor:
 +
 +
<code>
 +
[root@cdot-guru-4-1/]#./check_mounted_disks
 +
"OK: All disks are mounted and persistent"</code>
  
 
== 6.0 IRC Notification Bot Configuration (Server configuration) ==
 
== 6.0 IRC Notification Bot Configuration (Server configuration) ==
Line 884: Line 907:
  
 
== 7.0 Client Installation ==
 
== 7.0 Client Installation ==
 
  
 
'''7.1 Create Account Information on Client Machine'''
 
'''7.1 Create Account Information on Client Machine'''
Line 944: Line 966:
 
<code>yum -y install openssl-devel</code>
 
<code>yum -y install openssl-devel</code>
  
 
 
3. Instal Plugins:
 
3. Instal Plugins:
  

Latest revision as of 21:03, 17 December 2010

Version 0.7


1.0 About Nagios

Nagios logo.png

Nagios is a system and network monitoring application. It watches hosts and services that you specify, and provides critical notifications to administrators, when the system/network performance is being negatively impacted.

Nagios was originally designed to run under Linux, but it possessess the capability of being compatible with a host of other OSs as well.

Some of the many features of Nagios include:

  • Monitoring of network services (SMTP, POP3, HTTP, NNTP, PING, etc.)
  • Monitoring of host resources (processor load, disk usage, etc.)
  • Simple plug-in design that allows users to easily develop their own service checks
  • Parallelized service checks
  • Ability to define network host hierarchy using "parent" hosts, allowing detection of and distinction between hosts that are down and those that are unreachable
  • Contact notifications when service or host problems occur and get resolved (via email, pager, or user-defined method)
  • Ability to define event handlers to be run during service or host events for proactive problem resolution
  • Automatic log file rotation
  • Support for implementing redundant monitoring hosts
  • Optional web interface for viewing current network status, notification and problem history, log file, etc.

2.0 Server Installation (using tarball)

This guide will provide you with instructions on how to install Nagios from source (code) on Fedora 13 and have it monitoring your local and client machines.

2.1 Features available after instalation

  • Nagios and the all plugins will be installed underneath /usr/local/nagios
  • Nagios will be configured to monitor a few aspects of your local system (CPU load, disk usage, etc.)
  • Monitor Nagios clients

2.2 Prerequisites

During portions of the installation you will need to have root access to your machine.

Note: root password is **********

Make sure you've installed the following packages on your Fedora 13 installation before continuing.

  • Apache
  • PHP
  • GCC compiler
  • GD development libraries
Note: you have to be root to install the following packages.

yum install httpd php

yum install gcc glibc glibc-common

yum install gd gd-devel


2.3 Create Account Information

1. While you still have root privilages from a previous step, create a new nagios user account and give it a password.

useradd -m nagios

passwd **********

2. Create a new nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user to the group.

groupadd nagcmd

usermod -a -G nagcmd nagios

usermod -a -G nagcmd apache


2.4 Download Nagios and the Plugins

1. Create a directory for storing the downloads.

mkdir ~/nagios/downloads

cd ~/nagios/downloads

Download the source code tarballs of both Nagios and the Nagios plugins (visit http://www.nagios.org/download/ for links to the latest versions).

wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.2.3.tar.gz

wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.15.tar.gz

2.5 Compile and Install Nagios

1. Extract the Nagios source code tarball.

cd ~/nagios/downloads

tar xzf nagios-3.2.3.tar.gz

cd nagios-3.2.3

2. Run the Nagios configure script, passing the name of the group you created earlier, using the following command:

./configure --with-command-group=nagcmd

3. Compile the Nagios source code.

make all

4. Install binaries, init script, sample config files and set permissions on the external command directory.

Note: You have to be root to issue the following commands.

make install

make install-init

make install-config

make install-commandmode

Note: DO NOT start Nagios yet

2.6 Customize Configuration

Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you'd like to use for receiving alerts.

vi /usr/local/nagios/etc/objects/contacts.cfg

define contact{

  contact_name    nagiosadmin                 ; Short name of user

  use             generic-contact             ; Inherit default values from generic-contact template(defined above)

  alias           Nagios Admin                ; Full name of user

  email           email@learn.senecac.on.ca   ; *****CHANGE THIS TO YOUR EMAIL ADDRESS *****

        }

2.7 Configure the Web Interface

1. Install the Nagios web config file in the Apache conf.d directory.

cd /home/nagios/downloads/nagios-3.2.3

Note: you have to be root to issue the following command. 

make install-webconf

2. Create a nagiosadmin account for logging into the Nagios web interface.

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Type the password: **********

3. Restart Apache to make the new settings take effect.

service httpd restart

2.8 Compile and Install the Nagios Plugins

1. Extract the Nagios plugins source code tarball.

cd ~/downloads

tar xzf nagios-plugins-1.4.15.tar.gz

cd nagios-plugins-1.4.15

2. Compile and install the plugins.

./configure --with-nagios-user=nagios --with-nagios-group=nagios

make

Note: you have to be root to issue make install command.

make install

2.9 Start Nagios

1. Add Nagios to the list of system services and have it automatically start when the system boots.

chkconfig --add nagios

chkconfig nagios on

2. Verify the sample Nagios configuration files.

/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

You have to have no warnings or errors:

Total Warnings: 0
Total Errors: 0

3. If there are no errors, start Nagios. If you got errors, please check nagios.cfg file in step 2, and try it again.

service nagios start

2.10 Modify SELinux Settings

Fedora ships with SELinux (Security Enhanced Linux) installed and in Enforcing mode by default. This can result in "Internal Server Error" messages when you attempt to access the Nagios CGIs.

1. See if SELinux is in Enforcing mode.

getenforce

2. Put SELinux into Permissive mode.

setenforce 0

3. To make this change permanent, you'll have to modify the settings in /etc/selinux/config and reboot. Instead of disabling SELinux or setting it to permissive mode, you can use the following command to run the CGIs under SELinux enforcing/targeted mode:

chcon -R -t httpd_sys_content_t /usr/local/nagios/sbin/

chcon -R -t httpd_sys_content_t /usr/local/nagios/share/

2.11 Login to the Web Interface

You should now be able to access the Nagios web interface at the URL below. You'll be prompted for the username (nagiosadmin) and password you specified earlier. For a password that you configured please refere to the section 2.7, step 2.

http://localhost/nagios/

Click on the "Service Detail" navigational bar link to see details of what's being monitored on your local machine. It will take a few minutes for Nagios to check all the services associated with your machine, as the checks are spread out over time.

2.12 Open Port 5666 on Firewall

Make sure your machine's firewall rules are configured to allow access to the web server if you want to access the Nagios interface remotely.

1. Create a rule for iptables.

iptables -I INPUT -p tcp -m tcp ---dport 5666 -j ACCEPT

2. Save the new iptables rule so it will survive machine reboots.

service iptables save

2.13 You're Done

Congratulations! You sucessfully installed Nagios. Your journey into monitoring is just beginning. You have just completed the basic configuration of the Nagios Server. You'll no doubt want to monitor more than just your local machine, so keep reading and you will find how to configure the client machine with some modifications on Nagios server. If you did everything as per specifications, the following page will be displayed upon initial access of the Nagios Server GUI:


Nagios

3.0 Additional Server configuration

3.1 Downlad and Install NRPE Plugin for Nagios Server

1. Create a Nagios_NRPE folder.

mkdir -p ~/Nagios/Nagios_NRPE

cd ~/Nagios/Nagios_NRPE

2. Save file to directory ~/Nagios

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

3. Extract the Files:

tar -xzf nrpe-2.12.tar.gz

cd nrpe-2.12

3.2 Compile and Configure NRPE

Note: you have to be root to issue make install command.

./configure

make all

make install-plugin

3.3 Test Connection to NRPE daemon on Remote Server

Make sure that the NRPE on your Nagios server can talk to the NRPE daemon on the remote server we want to monitor. Replace “<IP of Remote Server>” with the remote servers IP address.

/usr/local/nagios/libexec/check_nrpe -H 142.204.133.90 NRPE v2.12

3.4 Create NRPE Command Definition

Note: The command.cfg file does not exist in /usr/local/nagios/etc/ directory so 
it has to be created, and the script block has to be added to the aformentioned file.

1. A command definition needs to be created in order for the check_nrpe plugin to be used by nagios.

vi /usr/local/nagios/etc/objects/commands.cfg

2. Add the following at the end of the file:

define command{         

              command_name check_nrpe         

              command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$

         }

3.5 Create host and service definitions

You'll need to create some object definitions in order to monitor the remote Linux/Unix machine. These definitions can be placed in their own file or added to an already exiting object configuration file.

First, create a new template for each different type of host you'll be monitoring. Let's create a new template for Linux boxes.

1. Create new linux-box-remote object template file:

vi /usr/local/nagios/etc/objects/linux-box-remote.cfg

Note: Information below is just an example of the template file.
define host{
          name                  linux-box-remote      ; 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                     ; DO NOT REGISTER THIS - ITS A TEMPLATE
          }

define host{
          use          linux-box-remote     ; Inherit default values from a template
          host_name    Centos5              ; The name we're giving to this server
          alias        Centos5              ; A longer name for the server
          address      142.204.133.90       ; IP address of the server
          }

define service{
          use                 generic-service
          host_name           Centos5
          service_description CPU Load
          check_command       check_nrpe!check_load
          }
define service{
          use                 generic-service
          host_name           Centos5
          service_description Current Users
          check_command       check_nrpe!check_users
          }
define service{
          use                 generic-service
          host_name           Centos5
          service_description /dev/hda1 Free Space
          check_command       check_nrpe!check_hda1
          }
define service{
          use                 generic-service
          host_name           Centos5
          service_description Total Processes
          check_command       check_nrpe!check_total_procs
          }
define service{
          use                 generic-service
          host_name           Centos5
          service_description Zombie Processes
          check_command       check_nrpe!check_zombie_procs
          }

2. Activate the linux-box-remote.cfg template:

vi /usr/local/nagios/etc/nagios.cfg

And add the following lines:

# Definitions for monitoring remote Linux machine

cfg_file=/usr/local/nagios/etc/objects/linux-box-remote.cfg

3. Verify Nagios Configuration Files:

If there are errors, fix them. If everything is fine, restart Nagios.

/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

You have to have no warnings or errors:

Total Warnings: 0

Total Errors: 0

4. Restart Nagios:

service nagios restart

4.0 Server Installation (using yum utility)

4.1 Required packages

Make sure you've installed the following packages on your Fedora 13 installation before continuing.

Note: You have to be root to install the following packages.

1. Install the following packages using yum install utility.

yum -y install httpd gcc glib glibc-common gd gd-devel

yum -y install nagios

yum -y install nagios-plugin-all

yum -y install nrpe

4.2 Create Account Information

1. While you still have root privileges from a previous step, create a new nagios user account and give it a password.

useradd -m nagios

passwd (your password is here)

2. Create a new nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user to the group.

groupadd nagcmd

usermod -a -G nagcmd nagios

usermod -a -G nagcmd apache

4.3 Configure the Web Interface

1. Create a nagiosadmin account for logging into the Nagios web interface.

htpasswd -c /etc/nagios/htpasswd.users nagiosadmin

Type the password: (your password is here)

Note: When you have installed all the required plugins,  using the “yum” utility, you will have to exhibit due diligence by
ensuring that  the “check_nrpe” plugin and check_nagios plugin are located in the /usr/lib64/nagios/plugins directory. If the 
check_nrpe plugin is not present you will have to either copy it from a compatible machine that already contains the appropriate
or required plugin(s),or try uninstalling the previous installation of the nagios plugins and proceed to re-installing the plugins,
using yum install. 

4.4 Nagios Configuration File

Note: Here is view of what your configuration files should look like, in order to have successfully installed and configured version of
Nagios. The following lines were either added or modified for the nagios.cfg file on the Nagios monitoring host.

1. Open nagios.cfg and edit it with your favourite editor.

vi /etc/nagios/nagios.cfg

#Definitions for monitoring the local (Linux) host

  cfg_file=/etc/nagios/objects/localhost.cfg

#Definitions for monitoring a Remote (Linux) machine

  cfg_file=/etc/nagios/objects/linux-remote.cfg

#Definitions for monitoring second Remote (Linux) machine

  cfg_file=/etc/nagios/objects/linux-romania.cfg

2. Open nrpe.cfg and edit it with your favourite editor.

vi /etc/nagios/nrpe.cfg

Note: In the nrpe.cfg  the following lines can be modified to meet the current system needs

#Allowed_hosts=127.0.0.1 is typically altered on the Remote host ONLY changes in IP address that allows a host to access the nrpe daemon system depends on an entity/organizations network requirements.

Note: The following examples use hardcoded command arguments

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_hda1]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /dev/hda1

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 700 -c 900

Note: If you're running the NRPE daemon as a standalone daemon you'll need to restart it (using the command service nrpe restart). 

4.5 Create a command definition

Note: You'll need to create a command definition in one of your Nagios object configuration files in order to use the 
check_nrpe plugin. Open the sample commands.cfg file for editing...

vi /etc/nagios/objects/commands.cfg

and add the following definition to the file:

define command{

command_name check_nrpe

command_line /usr/lib64/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -c $ARG1$

}

You are now ready to start adding services that should be monitored on the remote machine to the Nagios configuration...

4.6 Edit the localhost.cfg file located in the /etc/nagios/objects directory

Note: The localhost.cfg file can be created from one of the templates.cfg files located in the /etc/nagios/objects 
directory, here is a  brief view of how your localhost.cfg file should appear
# Define a host for the local machine

define host{

            use                     linux-server     ; Name of host template$

                                                     ; This host definition $

                                                     ; in (or inherited by) $

            host_name               localhost

            alias                   chile   #Example machine in this scenario

            check_interval          5

            retry_interval          1

            max_check_attempts      10

            check_command           check-host-alive

            notification_period     24x7

            notification_interval   24x7

            notification_options    d,r

            contact_groups          admins

            address                 127.0.0.1

}

4.7 Contacts Configuration File

1. Edit contacts.cfg file is pretty straight forward and easy to decipher.

vi /etc/nagios/objects/contacts.cfg

#CONTACTS################################################################

# Just one contact defined by default - the Nagios admin (that's you)

# This contact definition inherits a lot of default values from the 'generic-contact'

# template which is defined elsewhere.

define contact{

               contact_name    nagiosadmin                  ; Short name of user

               use             generic-contact              ; Inherit default values from generic-contact template(defined above)

               alias           Nagios Admin                 ; Full name of user

               email           email@learn.senecac.on.ca    ; ß CHANGE THIS TO YOUR EMAIL ADDRESS ******

        }

4.8 ScriptAlias NAGIOS.CFG

Note: ScriptAlias directory path will differ based on what version of OS (Operating System) you are running on your machine.

1. Edit nagios.cfg file located in apache (httpd) config files directory.

vi /etc/httpd/conf.d/nagios.cfg

Note: The current machine has Fedora 13, however, for a machine running Fedora 12 it may differ eg. ScriptAlias /nagios
/cgi-bin “/usr/lib64/nagios/cgi-bin/” It's important that these directory paths exist and contain the appropriate content.

ScriptAlias /nagios/cgi-bin/ "/usr/local/sbin/"

<Directory "/usr/local/sbin">

# SSLRequireSSL

Options ExecCGI Indexes

AllowOverride None

Order allow,deny

Allow from all

# Order deny,allow

# Deny from all

# Allow from 127.0.0.1

AuthName "Nagios Access"

AuthType Basic

AuthUserFile /etc/nagios/htpasswd.users

Require valid-user

</Directory>


Alias /nagios "/usr/share/nagios/html"

<Directory "/usr/share/nagios/html">

# SSLRequireSSL

Options Indexes

AllowOverride None

Order allow,deny

Allow from all

# Order deny,allow

# Deny from all

# Allow from 127.0.0.1

AuthName "Nagios Access"

AuthType Basic

AuthUserFile /etc/nagios/htpasswd.users

Require valid-user

</Directory>

4.9 Note: This section highlights a brief snippet of two critical detailed steps REQUIRED for the installation and successful configuration of a Remote host (on an ARM machine) Cdot-guru-4-1 (Utilize the installation steps (5.0) that follow this section).

Using the 'yum utility' install the nrpe daemon/ nrpe addon & required plugins

The nrpe.d directory is located in /etc/nagios/nrpe.d

The nagios plugins are located in directory path /usr/lib/nagios/plugins

1. Ensure that the required plugins are located in current directory paths.

Open nrpe.cfg and edit it with your favourite editor.

vi /etc/nagios/nrpe.cfg

Note: Hong Kong has two NICs so the allowed_hosts entry would be entered twice with the two corressponding IPs for both NICs

allowed_hosts=<Both the External & Internal IP Address for the monitoring hosts>

comment out the line:

#allowed_hosts=127.0.0.1

2. Change ownership on the plugins directory to reflect ownership to nagios.

chown nagios.nagios /usr/lib64/nagios/plugins

5.0 Setting up the Remote Host (using yum utility)

Note: This section will show how to setup the remote host with the nrpe daemon/nrpe addon & required plugins.

1. To install the nrpe daemon and nagios plugins run the following commands.

yum -y install nrpe

yum -y install Nagios-plugins-all

2. Open nrpe.cfg and edit it with your favourite editor.

vi /etc/nagios/nrpe.cfg

Add an allowed_hosts IP Address to nrpe.cfg file eg. 142.204.133.123 (chile’s IP Address), but for future configurations Hong Kong's IP Address will be used:

Allowed_hosts=142.204.133.123

3. Test the nrpe daemon locally using the command:

netstat -at | grep nrpe

Note: The output of the command should look something like this:

 tcp 0 0 *:nrpe *:* LISTEN

4. Add a firewall rule to the INPUT chain - CAVEAT: The ARM machines do not utilize iptables, so the line below may not be required.

iptables -I INPUT -p tcp -m tcp --dport 5666 -j ACCEPT

5. Save the firewall settings so it survives reboot

service iptables save

Note: Files locations after install:

/etc/nagios/ -> contains the nrpe.cfg

/etc/nrpe.d -> contains the daemon

/usr/lib64/nagios/plugins -> contains all plugins added during install

/usr/sbin/nrpe -> contains the nrpe execution file

/usr/share/docs/nrpe-2.12 -> contains the related README, Changelog files and .pdf etc

6. Check to make sure the NRPE daemon is functioning properly. To accomplish this, run the check_nrpe plugin that was installed for testing purposes. The directory make be different depending OS.

/usr/local/nagios/libexec/check_nrpe -H localhost <ip of the Remote host>

Or

/usr/lib64/naigos/plugins/check_nrpe -H localhost <ip of the Remote host>

7. Some of these commands can be executed on the Remote host for testing daemon functionality

/usr/local/nagios/libexec/check_nrpe -H localhost -c check_users

/usr/local/nagios/libexec/check_nrpe -H localhost -c check_load

/usr/local/nagios/libexec/check_nrpe -H localhost -c check_hda1

/usr/local/nagios/libexec/check_nrpe -H localhost -c check_total_procs

/usr/local/nagios/libexec/check_nrpe -H localhost -c check_zombie_procs

8. At this point your installation and configuration of both the Nagios monitoring host and Remote host should be completed successfully. First ensure that your apache server and nagios is running on the corresponding monitoring host. To achieve a Frontend (GUI) view of Nagios functionality, go to your browser address field and type in the url-> http://<ip address of monitoring host goes here>/nagios. At the authentication prompt enter the username and password you set during the installation process.

5.1 Additional Details

This section will discuss some additional initiatives that were implemented on the Nagios Remote host. Due to the inability to obtain
a plugin that is capable of monitoring mounted devices (on ARM machines) upon boot. A supplemental perl script was identified and
utilize for this purpose. The check_mounted_disks script was conveniently added to /etc/init.d directory, and a few symlinks
(soft links)were linked to appropriate runlevels on the ARM system. Once the system is rebooted the aforementioned script will
execute automatically and perform a verification check of all devices that should be mounted on boot.

1. Symlinks were created using the command syntax.

ln -s /etc/init.d/check_mounted_disks /etc/rc/rc2.d/S50check_mounted_disks
      
ln -s /etc/init.d/check_mounted_disks /etc/rc/rc2.d/K50check_mounted_disks

2. When the check_mounted_disks script is executed on the command line, the following results are exhibited on the display monitor:

[root@cdot-guru-4-1/]#./check_mounted_disks
"OK: All disks are mounted and persistent"

6.0 IRC Notification Bot Configuration (Server configuration)

Note: please keep in mind this was done on Fedora 13 with Nagios 3.2.3 and NagIRCBot 0.0.30.

1. Download the IRC bot.

wget http://www.vanheusden.com/nagircbot/nagircbot-0.0.30.tgz

2. Unzip the archive.

tar -xvzf nagircbot-0.0.30.tgz

3. Become the root user.

su –

4. Install edition packages.

yum install openssl-devel

yum nstall gcc

5. After unpacking the tarball, in the Makefile you must change the following line:

from:

LDFLAGS+=$(DEBUG) -lssl -lstdc++

to:

Note: only has to be done sometimes, when you getting an error about lcrypto

LDFLAGS+=$(DEBUG) -lssl -lstdc++ -lcrypto

6. When you change the make file from the step 3, issue make/make install.

make

make install

7. Once its installed you can start up nagircbot:

nagircbot -f /var/log/nagios/status.dat -s irc.freenode.net:6667 -c \#seneca-cdot -C -n test22283833 -u NagiosBot -U NagiosIRCBot -I 900

8. Lets examine the command from step 5, which will be the main command for starting nagircbot:


/var/log/nagios/status.dat Points to the log file it will read
irc.freenode.net:6667 IRC server
mathon Channel name
The "-C" flag Allows it to send colored messages
test22283833 IRCnickname
ident/realname The ident and real name string for the bot
The "-I" flag 900 How often to send a message to the channel in this case its 15min (900 seconds)








9. Additional information about Nagios Bot.

Nagios bot options can be queried on the IRC channel. If you open private messages with the bot you can issue and control it by using the following commands:

help gets help
resend resend the last known problems
statistics returns the number of criticals/warnings/etc
reload completely forced reload the nagios status
check check if nagios is still running






10.Congratulations! You just completed the IRC bot configuration.

Nagios IRC Bot

7.0 Client Installation

7.1 Create Account Information on Client Machine

SSH to Iraq machine (142.204.133.98) and issue the following commands:

1. Become the root user.

su -

2. Create a new nagios user account and give it a password.

useradd -m nagios

passwd (your password is here)

3. Create a folder for Nagios plugins.

mkdir ~/downloads

cd ~/downloads

Note: For the next step make sure you are connected to the Internet to download nagios plugins.

4. Download the source code tarball of the NRPE addon (visit http://www.nagios.org/download/ for links to the latest versions).

wget http://osdn.dl.sourceforge.net/sourceforge/nagios/nrpe-2.8.tar.gz

5. Extract the NRPE source code tarball.

tar xzf nrpe-2.8.tar.gz

cd nrpe-2.8

6. Compile the NRPE add-on.

./configure

make all

7. Install the NRPE plug-in.

make install-plugin

7.2 Compile and Configure Nagios Plugins

Note: You need openssl-devel package installed to compile plugins with ssl support.

You have to be root to issue make install commands.

1. Become root user.

su -

2. Install openssl-devel package.

yum -y install openssl-devel

3. Instal Plugins:

./configure --with-nagios-user=nagios --with-nagios-group=nagios

make

make install

4. The permissions on the plugin directory and the plugins will need to be changed to nagios user.

chown nagios.nagios /usr/local/nagios

chown -R nagios.nagios /usr/local/nagios/libexec

5. Package xinted is needed.

yum install xinetd

6. Start xinetd service.

service xinetd start

7.3 Downlad and Install NRPE Daemon

1. Create a forlder ~/Nagios/Nagios_NRPE.

mkdir -p ~/Nagios/Nagios_NRPE

cd ~/Nagios/Nagios_NRPE

Save file to directory ~/Nagios

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

2. Extract the files:

tar -xzf nrpe-2.12.tar.gz

cd nrpe-2.12

7.4 Compile and Configure NRPE

1. Install NRPE:

Note: you have to be root to issue make install command.

./configure

General Options:  
----------------------  
NRPE port:      5666  
NRPE user:      nagios  
NRPE group:     nagios  
Nagios user:    nagios  
Nagios group:   nagios  

make all

make install-plugin

make install-daemon

make install-daemon-config

make install-xinetd

7.5 Post NRPE Configuration

1. Edit Xinetd NRPE entry:

Add Nagios Monitoring server to the “only_from” directive.

vi /etc/xinetd.d/nrpe only_from = 127.0.0.1 <142.204.133.90 >

2. Edit services file entry and add entry for nrpe daemon.

vi /etc/services

nrpe      5666/tcp    # NRPE

3. Restart Xinetd and set to start at boot:

chkconfig xinetd on

service xinetd restart

7.6 Test NRPE Daemon Install

1. Check NRPE daemon is running and listening on port 5666:

netstat -at |grep nrpe

2. Output should be:

tcp    0    0 *:nrpe    *.*    LISTEN

3. Check NRPE daemon is functioning:

/usr/local/nagios/libexec/check_nrpe -H localhost

4. Output should be NRPE version:

NRPE v2.12

7.7 Open Port 5666 on Firewall

Note: Make sure to open port 5666 on the firewall of the remote server so that the Nagios monitoring server can access the NRPE daemon.

1. Create a rule for iptables.

iptables -I INPUT -p tcp -m tcp ---dport 5666 -j ACCEPT

2. Save the new iptables rule so it will survive machine reboots.

service iptables save

7.8 Congratulations

Congratulations! You have successfully completed the configuration of the Nagios Server/Client setup.

8.0 Demonstration

Network map
Host Status Details
System Status Details
Services Detail Pane