Nagios 4.1.1: Nagios Core 4.1.1 Installation on Centos 6.7

Nagios Core 4.1.1

This is a guide on installing the latest Nagios Core (4.1.1) on Centos 6.7. Nagios is an open source computer system monitoring, network monitoring and infrastructure monitoring software application. Nagios offers monitoring and alerting services for servers, switches, applications, and services. It alerts the users when things go wrong and alerts them a second time when the problem has been resolved. Nagios Core is the monitoring and alerting engine that serves as the primary application around which hundreds of Nagios projects are built. It serves as the basic event scheduler, event processor, and alert manager for elements that are monitored. It features several APIs that are used to extend its capabilities to perform additional tasks, is implemented as a daemon written in C for performance reasons, and is designed to run native on Linux/*nix systems.

Step 1: Install Required Dependencies

We need to install Apache, PHP and some libraries like gcc, glibc, glibc-common and GD libraries and its development libraries before installing Nagios 4.0.1 with source. And to do so we can use the yum default package installer.

# yum install -y httpd php gcc glibc glibc-common gd gd-devel make net-snmp perl-rrd xinetd openssl-devel package perl-GD* ntp perl-rrd*

Step 2: Create Nagios User and Group so that application will configure the server perfectly.

Create a new "nagios" user and "nagcmd" group account and set a password.

# useradd nagios

# groupadd nagcmd

Next, add both the nagios user and the apache user to the nagcmd group.

Step 3: Add both the nagios user and the apache user to the nagcmd group.

# usermod -G nagcmd nagios

# usermod -G nagcmd www-data (for some if www-data is not theere use apache)

Step 4: Download Nagios Core 4.0.1 and Nagios Plugin 1.5

Create a directory for your
Nagios installation and all its future downloads.

# mkdir /root/nagios

# cd /root/nagios

Nowdownload latest Nagios Core 4.1.1 and the Nagios plugins 2.1.1 packages from the below Links

Nagios 4.1.1 Core Software Download and Installation:

# wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-4.1.1.tar.gz

Nagios Plugins:

# wget https://www.nagios-plugins.org/download/nagios-plugins-2.1.1.tar.gz

Step 5: Installting Nagios Core

We need to extract downloaded package with tar command as follows.

# tar –xvf nagios-4.1.1.tar.gz

When you extract these tar files with tar command, two new folders will appear in that directory.

Step 6: Configure & Install Nagios Core Server Components

Now, first we will configure Nagios Core and to do so we need to go to Nagios directory and run configure file and if everything goes fine, it will show the output in the end as sample output. Please see below.

# cd nagios-4.1.1

#./configure --prefix=/usr/local/nagios --with-nagios-user=nagios --with-nagios-group=nagios --with-command-user=nagios --with-command-group=nagcmd

Output:

General Options:

-------------------------

Nagios executable: nagios

Nagios user/group: nagios,nagios

Command user/group: nagios,nagcmd

Event Broker: yes

Install ${prefix}: /usr/local/nagios

Install ${includedir}: /usr/local/nagios/include/nagios

Lock file: ${prefix}/var/nagios.lock

Check result directory: ${prefix}/var/spool/checkresults

Init directory: /etc/init.d

Apache conf.d directory: /etc/httpd/conf.d

Mail program: /usr/bin/mail

Host OS: nagios.test.com

Web Interface Options:

------------------------

HTML URL: http://localhost/nagios/

CGI URL: http://localhost/nagios/cgi-bin/

Traceroute (used by WAP): /usr/sbin/traceroute

Review the options above for accuracy. If they look okay,

type 'make all' to compile the main program and CGIs

*** Main program, CGIs and HTML files installed ***

Now, after configuring we need to Compile and install all the binaries with make command and make install command will install all the needed libraries in your machine and we can proceed further.

# make all

# make install

Output:

You can continue with installing Nagios as follows (type 'make'
without any arguments for a list of all possible options):

make install-init

- This installs the init script in /etc/rc.d/init.d

make install-commandmode

- This installs and configures permissions on the

directory for holding the external command file

make install-config

- This installs sample config files in /usr/local/nagios/etc

# make install-init

To make nagios work from the command line we need to install command-mode.

# make install-commandmode

Next, install sample nagios files, please run following command.

# make install-config

Output:

/usr/bin/install -c -m 775 -o nagios -g nagios -d /usr/local/nagios/etc

/usr/bin/install -c -m 775 -o nagios -g nagios -d /usr/local/nagios/etc/objects

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/nagios.cfg /usr/local/nagios/etc/nagios.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/cgi.cfg /usr/local/nagios/etc/cgi.cfg

/usr/bin/install -c -b -m 660 -o nagios -g nagios sample-config/resource.cfg /usr/local/nagios/etc/resource.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/templates.cfg /usr/local/nagios/etc/objects/templates.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/commands.cfg /usr/local/nagios/etc/objects/commands.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/contacts.cfg /usr/local/nagios/etc/objects/contacts.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/timeperiods.cfg /usr/local/nagios/etc/objects/timeperiods.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/localhost.cfg /usr/local/nagios/etc/objects/localhost.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/windows.cfg /usr/local/nagios/etc/objects/windows.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/printer.cfg /usr/local/nagios/etc/objects/printer.cfg

/usr/bin/install -c -b -m 664 -o nagios -g nagios sample-config/template-object/switch.cfg /usr/local/nagios/etc/objects/switch.cfg

*** Config files installed ***

Remember, these are *SAMPLE* config files. You'll need to read

the documentation for more information on how to actually define

services, hosts, etc. to fit your particular needs.

Step 8: Install and Configure Web Interface for Nagios

We are done with all configurations in the backend, now we will configure Web Interface For Nagios
with following command. The below command will Configure Web interface for Nagios and a web admin user will be created “nagiosadmin”.

# make install-webconf

In this step, we will be creating a password for “nagiosadmin”. After executing this command, please
provide a password twice and keep it remember because this password will be used when you login in the Nagios Web interface.

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

New password:

Re-type new password:

Adding password for user nagiosadmin

Step 9: Restart Apache to make the new settings take effect.

# service httpd start

Step 10: Configure and Install Nagios Plugin

We have downloaded nagios plugins in /root/nagios, Go there and configure and install it as directed
below.

# cd /root/nagios

# cd tar –xvf nagios-plugins-2.1.1.tar.gz

# ./configure --with-nagios-user=nagios --with-nagios-group=nagios --with-openssl=/usr/bin/openssl --enable-perl-modules --enable-libtap

# make

# make install

Step 11: Verify Nagios Configuration Files

Now we are all done with Nagios configuration and its time to verify it and to do so please insert
following command. If everything goes smoothly it will show up similar to below output.

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

Output:

Nagios Core 4.1.1

Last Modified: 08-19-2015

License: GPL

Website: https://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 7 services.

Checked 1 hosts.

Checked 1 host groups.

Checked 0 service groups.

Checked 1 contacts.

Checked 1 contact groups.

Checked 7 commands.

Checked 5 time periods.

Checked 0 host escalations.

Checked 0 service escalations.

Checking for circular paths...

Checked 1 hosts

Checked 0 service dependencies

Checked 0 host dependencies

Checked 1 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

Step 12: Restart the Nagios services.

# service nagios restart

To make Nagios work across reboots, we need to add nagios and httpd with chkconfig command.

# chkconfig --add nagios

# chkconfig --level 35 nagios on

# chkconfig --add httpd

# chkconfig --level 35 httpd on

Step 13: Login to the Nagios Web Interface http://yourhostip/nagios

Your nagios is ready to work, please open it in your browser with “http://Your-server-IP-address/nagios” or “http://FQDN/nagios” and Provide the username “nagiosadmin” and password.

Download and Install NRPE

NRPE allows you to remotely execute Nagios plugins on other Linux/Unix machines. This allows you to monitor remote machine metrics (disk usage, CPU load, etc.). NRPE can also communicate with some of the Windows agent addons, so you can execute scripts and check metrics on remote Windows machines as well.

Step 14: First we needed to create the right folders:

# mkdir -p /usr/local/src/nrpe

# cd /usr/local/src/nrpe

Download the files and extract:

# wget http://kent.dl.sourceforge.net/project/nagios/nrpe-2.x/nrpe-2.15/nrpe-2.15.tar.gz

# tar -xf nrpe-2.15.tar.gz

# cd nrpe-2.15

Because of an issue with the openssl library folder we need to use another path than /usr/lib:

#./configure --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib/x86_64-linux-gnu

Now make and make install:

# make all

Next, install the NRPE plugin daemon, and sample daemon config file.

# make install-plugin

# make install-daemon

# make install-daemon-config

Install the NRPE daemon under xinetd as a service.

# make install-xinetd

Next, open /etc/services file add the following entry for the NRPE daemon at the bottom of the file.

# vi /etc/services

nrpe 5666/tcp NRPE

Restart the xinetd service.

# service xinetd restart

Step 15: Verify NRPE Daemon Locally

Run the following command to verify the NRPE daemon working correctly under xinetd.

# netstat -at | grep nrpe

tcp 0 0 *:nrpe *:* LISTEN

Step 16: Verify the NRPE daemon is functioning properly.

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

Output: ( Which shows the NRPE version)

NRPE v2.15

Now we needed to create two configuration files so that we can monitor Linux or Unix machines

Step 17: To add the host:

# cd /usr/local/nagios/etc

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

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

heck_command check-host-alive

notification_period 24x7

notification_interval 30

notification_options d,r

contact_groups admins

}

define host{

use linux-box ; Inherit default values from a template

host_name Testbox ; The name we're giving to this server

alias CentOS 6.7 ; A longer name for the server

address 192.168.1.84 ; IP address of Remote Linux host

}

Step 18 To add the services:

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

define service{

  use   generic-service

host_name   Testbox

service_description CPU Load

check_command check_nrpe!check_load

}

define service{

  use   generic-service

host_name   Testbox

service_description Total Processes

check_command check_nrpe!check_total_procs

}

define service{

  use   generic-service

host_name   Testbox

service_description Current Users

check_command check_nrpe!check_users

}

define service{

  use   generic-service

host_name   Testbox

service_description Root Partition

check_command check_nrpe!check_disk

}

define service{

  use generic-service

host_name   Testbox

service_description Home Partition

check_command check_nrpe!check_disk_home

}

define service{

  use   generic-service

host_name   Testbox

service_description Ping Status

check_command check_ping!10.0,80%!50.0,90%

}

We needed to added this configuration files in nagios.cfg

# vi /usr/local/nagios/nagios.cfg

cfg_file=/usr/local/nagios/etc/hosts.cfg

cfg_file=/usr/local/nagios/etc/services.cfg

Now NRPE commands should definition needs to be created in commands.cfg file.

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

define command{

command_name check_nrpe

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

}

Finally, verify Nagios Configuration files for any errors.

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

# service nagios restart

Now your Nagios server is ready to monitor Linux machines

Also see:

Adding Nagios Linux host to Nagios core server

Adding Windows host to Nagios Core server

Adding MRTG to Nagios Core 4.1.1
Adding Nagios Graph to Nagios core 4.1.1
Fixing the nagios could not find the file nagios.cmd

Keywords: Nagios Core 4.1.1, Nagios Server, Nagios Monitoring Server, Minitor Basic services on Liunx, Linux Monitoring Server

Search This Blog

System Administrator Blog And Scripts