Nagios Monitoring server (CentOS 6.x)
Install Required Dependencies
We need to install Aapche, PHP and some libraries before installing Nagios.
[root@greenhat]# yum install -y httpd php gcc glibc glibc-common
gd gd-devel make net-snmp
Create Nagios User and Group
Create a new nagios user and nagcmd group
account and set a password.
[root@greenhat]# useradd nagios
[root@greenhat]# groupadd nagcmd
Next, add both the nagios user
and the apache user to the nagcmd group.
[root@greenhat]# usermod -G nagcmd nagios
[root@greenhat]# usermod -G nagcmd apache
Download Nagios Core 4.1.1 and Nagios Plugin 2.1
Create a directory for your Nagios installation
and all its future downloads.
[root@greenhat]# mkdir ~/nagios
[root@greenhat]# cd ~/nagios
Now download latest Nagios Core 4.1.1 and Nagios
plugins 2.1 packages with wget command.
[root@greenhat nagios~]# wget
https://assets.nagios.com/downloads/nagioscore
/releases/nagios 4.1.1.tar.gz
[root@greenhat nagios~]# wget
http://www.nagios-plugins.org/download/nagios-plugins-2.1.1.tar.gz
Extract Nagios Core and its Plugins
We need to extract downloaded package with tar command as
follows.
[root@greenhat nagios~]# tar xvf
nagios-4.1.1.tar.gz
[root@greenhat nagios~]# tar xvf
nagios-plugins-2.1.1.tar.gz
When you extract these tarballs with tar
command, two new folders will appear in that directory. Now, first we will configure Nagios
Core and to do so we need to go to Nagios directory
and run configure file.
[root@greenhat nagios~]# cd nagios-4.1.1
[root@greenhat nagios-4.1.1 ]# ./configure
--with-command-group=nagcmd
[root@greenhat nagios-4.1.1 ]# make all
[root@greenhat nagios-4.1.1 ]# make install
[root@greenhat nagios-4.1.1 ]# make install-init
[root@greenhat nagios-4.1.1 ]# make install-command mode
[root@greenhat nagios-4.1.1 ]# make install-config
Customizing Nagios Configuration
Open the “contacts.cfg” file with your
choice of editor and set the email address associated with the nagiosadmin contact definition to receiving email alerts.
[root@greenhat]# vi
/usr/local/nagios/etc/objects/contacts.cfg
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”.
[root@greenhat nagios-4.1.1 ]# 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.
[root@greenhat nagios-4.1.1]# htpasswd -s -c
/usr/local/nagios/etc/htpasswd.users nagiosadmin
Restart Apache to make the
new settings take effect.
[root@greenhat]# service httpd restart
Compile and Install Nagios Plugin
We have downloaded nagios plugins in ~/nagios,
Go there and configure and install it as directed below.
[root@greenhat nagios]# cd ~/nagios
[root@greenhat nagios]# cd
nagios-plugins-2.1.1
[root@greenhat nagios]# ./configure --with-nagios-user=nagios
--with-nagios-group=nagios
[root@greenhat nagios]# make
[root@greenhat nagios]# make install
Verify Nagios Configuration Files
Now we are all done with Nagios
configuration and it time to verify it by following
command.
[root@greenhat nagios]#
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Note: If it gives the following output then all configuration is
right.
Total Warnings: 0
Total Errors: 0
Add Nagios Services to System Startup
[root@greenhat]# chkconfig nagios on
[root@greenhat]# service nagios start
Login to the Nagios Web Interface
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.
Add Hosts
In the objects folder
we add our hosts/clients. Firstly we create host filename in object folder for
linux.
[root@greenhat]#vi
/usr/local/nagios/etc/objects/host.cfg
In this host file we
add our host name, address and its defined services which have to be monitor by
nagios.
E.g
define host{
use
linux-server
host_name
myhost
address
10.100.200.191
}
define service{
use
generic-service
host_name
myhost
service_description
Disk check
check_command
check_nrpe!check_sda3 }
Add Host in nagios
When we create host,
then we add its config file in nagios.cfg.
[root@greenhat ]#cd
/usr/local/nagios/etc/nagios.cfg
Add the hosts file in
nagios. e.g.
cfg_file=/usr/local/nagios/etc/objects/host.cfg
Restart the nagios
services and see the host in the nagios web interface
Remote Linux Host (Client)
Please use the below instructions to install Nagios
Plugins and NRPE daemon on the Remote Linux
Host.
Install Required Dependencies
We need to install required libraries like gcc, glibc, glibc-common and GD and
its development libraries before installing.
[root@greenhat]# yum install -y gcc glibc glibc-common gd gd-devel
make net-snmp openssl-devel
Create Nagios User
Create a new nagios user account and set a
password.
[root@greenhat]# useradd nagios
[root@greenhat]# passwd nagios
Install
the Nagios Plugins
Create a directory for installation and all
its future downloads.
[root@greenhat]# mkdir /root/nagios
[root@greenhat]# cd /root/nagios
Now download latest Nagios Plugins 2.1 package
with wget command.
[root@greenhat nagios~]# wget
http://www.nagios-plugins.org/download/nagios-plugins-2.1.1.tar.gz
Extract
Nagios Plugins
Run the following tar command
to extract the source code tarball.
[root@greenhat nagios~]# tar xvf
nagios-plugins-2.1.1.tar.gz
Compile and Install Nagios Plugins
Next, compile and install using following
commands
[root@greenhat nagios]# cd
nagios-plugins-2.1.1
[root@greenhat nagios]# ./configure
[root@greenhat nagios]# make
[root@greenhat nagios]# make install
Set the permissions on the plugin directory.
[root@greenhat nagios]# chown
nagios.nagios /usr/local/nagios
[root@greenhat nagios]# chown -R
nagios.nagios /usr/local/nagios/libexec
[root@greenhat nagios]# yum install
xinetd
Install NRPE Plugin
Download latest NRPE Plugin 2.15 packages
with wget command.
[root@greenhat]# cd /root/nagios
[root@greenhat]# wget http://liquidtelecom.dl.sourceforge.net/project/nagios/nrpe-2.x/nrpe-2.15/nrpe-2.15.tar.gz
[root@greenhat]# tar xzf
nrpe-2.15.tar.gz
[root@greenhat]# cd nrpe-2.15
[root@greenhat]# ./configure
[root@greenhat]# make all
[root@greenhat]# make install-plugin
[root@greenhat]# make install-daemon
[root@greenhat]# make install-daemon-config
Install the NRPE daemon under xinetd as a
service.
[root@greenhat]# make install-xinetd
Now open /etc/xinetd.d/nrpe file and add the localhost and IP
address of the Nagios Monitoring Server.
only_from = 127.0.0.1 localhost <nagios_ip_address>
Next, open /etc/services file
add the following entry for the NRPE daemon at the bottom of
the file.
nrpe
5666/tcp
NRPE
Restart the xinetd service.
[root@greenhat]# service xinetd restart
Verify NRPE Daemon Locally
Run the following command to verify the NRPE
daemon working correctly under xinetd.
[root@greenhat]# netstat -at | grep nrpe
tcp
0 0
*:nrpe
*:*
LISTEN
[root@greenhat]# /usr/local/nagios/libexec/check_nrpe -H
localhost
You will get a following string on the screen,
it shows you what version of NRPE is installed:
NRPE v2.15
Configure Firewall Rules
[root@greenhat]# iptables -A INPUT -p tcp -m tcp --dport 5666 -j
ACCEPT
Run the following command to save the new
iptables rule so it will survive at system reboots.
[root@greenhat]# service iptables save
Add port 5666 as trusted port in the firewall, if the firewall
enabled.
Customize
NRPE commands
The default NRPE configuration file that got
installed has several command definitions that will be used to monitor this
machine.
[root@greenhat]# vi
/usr/local/nagios/etc/nrpe.cfg
By default all service remain same as it is but the disk service
path/command should be changed. e.g
command[check_sda5]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p
/dev/sda5
By default memory and bandwidth command doesn’t exist but we can use scritps to helps nagios to monitor the required statistics.
For Bandwidth
http://greenwhitehat.blogspot.com/2016/03/add-bandwidth-plugin-in-nagios.html
For Memory
http://greenwhitehat.blogspot.com/2016/03/add-memory-plugin-in-nagios.html
On Nagios Monitoring Server
Install NRPE Plugin
Go to the nagios download directory and
download latest NRPE Plugin with wget command.
[root@greenhat]# cd /root/nagios
[root@greenhat]# wget
http://garr.dl.sourceforge.net/project/nagios/nrpe-2.x/nrpe-2.15/nrpe-2.15.tar.gz
[root@greenhat]# tar -xzf
nrpe-2.15.tar.gz
[root@greenhat]# cd nrpe-2.15
[root@greenhat]# ./configure
[root@greenhat]# make all
[root@greenhat]# make install-daemon
Verify NRPE Daemon Remotely
Make sure that the check_nrpe plugin
can communicate with the NRPE daemon on the remote Linux host.
Add the IP address in the command below with the IP address of
your Remote Linux host.
[root@greenhat]# /usr/local/nagios/libexec/check_nrpe -H <remote_linux_ip_address>
Now NRPE command definition needs to be
created in commands.cfg file.
[root@greenhat]# vi /usr/local/nagios/etc/objects/commands.cfg
define command{
command_name
check_nrpe
command_line
$USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
}
[root@greenhat]# service nagios restart
That’s it. Now go to Nagios Monitoring
Web interface at “http://Your-server-IP-address/nagios” or “http://FQDN/nagios” and
provide the username “nagiosadmin” and password. Check that
the Remote Linux Host was added and is being monitored.
We need to install Aapche, PHP and some libraries before installing Nagios.
[root@greenhat]# yum install -y httpd php gcc glibc glibc-common
gd gd-devel make net-snmp
Create Nagios User and Group
Create a new nagios user and nagcmd group account and set a password.
[root@greenhat nagios~]# wget https://assets.nagios.com/downloads/nagioscore
/releases/nagios 4.1.1.tar.gz
When you extract these tarballs with tar
command, two new folders will appear in that directory. Now, first we will configure Nagios
Core and to do so we need to go to Nagios directory
and run configure file.
Open the “contacts.cfg” file with your choice of editor and set the email address associated with the nagiosadmin contact definition to receiving email alerts.
Add Hosts
use generic-service
service_description Disk check
check_command check_nrpe!check_sda3 }
Install Required Dependencies
[root@greenhat]# mkdir /root/nagios
command[check_sda5]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/sda5
By default memory and bandwidth command doesn’t exist but we can use scritps to helps nagios to monitor the required statistics.
For Bandwidth
http://greenwhitehat.blogspot.com/2016/03/add-bandwidth-plugin-in-nagios.html For Memory
http://greenwhitehat.blogspot.com/2016/03/add-memory-plugin-in-nagios.html
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