DATACENTER MANAGEMENT NAGIOS CONFIGURATION

Submitted By

Pankaj U. Rane (120851923024)

P.Venkatesh(120851923027)

Install and configure Nagios on Fedora Core 8 (VM or Physical Machine)

Monitor the following:

>> Local Machine

>> Remote Linux Machine (preferably Fedora) – Hostname to be displayed as “LINUX1”

>> Remote Windows Machine – Hostname to be displayed as “WIN1”

>> Remote Website – Name to be displayed as “MYWEBSITE”

*** MONITORING THE WINDOWS MACHINE***

To achieve this , we need to install an agent on the WINDOWS Machine.

Agent acts as a proxy between the Nagios Plugin that does the monitoring and the

actual service or attribute of the windows machine.

Client used for this user manual is NSClient++

The check_nt plugin will be used to communicate with the NSClient++

Steps involved:

Perform first-time pre-requisite.

Install monitoring agent on the Windows Machine.

Create new host and service definitions for monitoring the Windows Machine.

Restart the Nagios daemon.

Download the NSClient++ installer package from www.nsclient.org to the target

machine you wish to install it on.

Run the NSClient++ MSI installer package to initiate the installation. The welcome

screen will appear. Click Next to continue to the next step.

Read through the End User License Agreement.

Once you have agreed to itsterms, check the acceptance box and click Next to

continue.

You may customize the installation options on the next screen if you wish. No

changes are required for an working installation of the agent. Click Next to continue.

If an existing NSClient++ installation exists on the target machine, you will have the

option of using the old configuration file. This option is not enable if this is the first

time you are installing the client. Click Next to continue.

In the next step you will need to configure the NSClient++ agent. These steps

are important! Make sure you: Enter the IP address of the Nagios XI or Nagios

Core server in the Allowed hosts box.

Enter a password in the NSClient password box that will be required for

communication between the Nagios server and the Windows machine.

Check the following boxes in the Modules to load section:

Enable common check plugins Enable , nsclient server (check_nt) , NRPE server

and WMI checks. Click Next to continue.

Click the Install button on the next screen to begin the installation.

When the installation completes, make sure to check the Start service option and click

Finish to complete the setup.

The NSClient++ agent will now be running as a service, which means the Windows

machine is ready to be monitored with Nagios.

And now to Start->Run->cmd->services.msc and click on NSClient++ and select

the Logon tab and enable “Allow service to interact with desktop” and click “OK”

and Restart the NSClient++ service.

NOW CONFIGURE FEDORA TO MONITOR WINDOWS

#nano /usr/local/nagios/etc/nagios.cfg

# Definitions for monitoring a Windows Machine

cfg_file=/usr/local/nagios/etc/objects/windows.cfg

uncomment the cfg_file and save nagios.cfg

*** NAGIOS SERVER INSTALLATION***

Before installing Nagios server check the pre-requistives :

apache - #yum list installed | grep httpd

php - #yum list installed | grep php

gcc compiler - # yum list installed | grep gcc

GD Development libraries - # yum list installed | grep gcc

net-snmp - # yum list installed | grep net-snmp (if not installed #yum install net-snmp)

Server Installation of Nagios :

Step1 : Create and manage account and group

a) Make sure you are in “root”

b) Create a new nagios user and give it a password

#whoami

root

#cat /etc/passwd

#useradd –m nagios ( -m : To create a user in home dir)

#ls /home/

nagios

#passwd nagios ( Set the password the nagios user)

c) Check if a group exist with the nagios name.

#cat /etc/group

#cat /etc/group | cut –d”:” –f1 | sort –u | less

nagios

d) Create a new nagcmd group for allowing external commands to be submitted through the

web interface.

#groupadd nagcmd

#cat /etc/group | grep nagcmd

nagcmd:x:502

e) Add both the nagios user and the apache user to the group.

#usermod –a –G nagcmd nagios

#usermod –a –G nagcmd apache

#cat /etc/group | grep nagcmd

nagcmd:x:502:nagios,apache

f) Download Nagios and Plugin Source Code.

nagios-3.4.1.tar.gz

nagios-plugins-1.4.16

g) Compile and install nagios

i) Extract the nagios source code tarball.

#tar xzf nagios-3.4.1.tar.gz

#ls –l

nagios-3.4.1

#cd nagios-3.4.1

nagios>#ls

ii) Run the nagios configure script, passing the name of the group you created earlier.

nagios>#./configure - -with-command-group=nagcmd

iii) Compile the nagios source code

nagios>#make all

iv) Install binaries , init scripts , sample config files and set permissions on the external

command directory.

nagios># make install

nagios># make install-init

nagios># make install-config

nagios># make install-commandmode

v) Configuration customization

#nano /usr/local/nagios/etc/objects/contact.cfg

Define contact {

email pankaj.rane2k8@gmail.com ; (Note: should be type in single line)

and save contact.cfg

vi) Configure the web interface

a) Install the nagios web config file in the Apache conf.d directory.

nagios># make install-webconf

b) Install the classic theme for the nagios web interface

nagios># make install-classicui

c) Create a nagiosadmin account for loggin into the nagios web interface.

Note : Remember the password of nagiosadmin

We will use the htpasswd for this , htpasswd is used to create and update the flat-files used to

store usernames and passwords for basic authentication of HTTP users.

#htpasswd –c /usr/local/nagios/etc/htpasswd.users

nagiosadmin

New passwd:nagiosadmin123

Re-type passwd:nagiosadmin123

#service httpd restart

#cd .. ( come out of nagios folder)

#ls –l

#tar xzf nagios-plugin.tar.gz

#cd nagios-plugin

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

#make

#make install

d) Start Nagios

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

#chkconfig - -add nagios

#chkconfig nagios on

The chkconfig command updates and queries runlevel information for system services.

Verify the sample nagios configuration files.

nagios-plugin>#/usr/local/nagios/bin/nagios –v /usr/local/nagios/etc/nagios.cfg

0 warnings

0 Errors

#service nagios start

SE-linux is in enforcing mode make it disabled.

#getenforce

Permissive

#setenforce 0 - To disable

Go to browser http://localhost/nagios/

Username : nagiosadmin

Password:nagiosadmin123

*** MONITORING THE REMOTE LINUX MACHINE***

How to?

Use the NRPE daemon to execute Nagios plugins on the remote server and report back to the

monitoring host server.NRPE-Nagios Remote Plugin Executor.

Step1: Remote server installation and setup ( Nagios client)

Check openssl-devel is installed

#yum list installed | grep openssl-devel

Create nagios user account on remote server to be monitored

#useradd nagios

#passwd nagios

New passwd:Password1234

Download and install Nagios Plugin nagios-plugin-1.4.16.tar.gz

#tar xzf nagios-plugin-1.4.16.tar.gz

#cd nagios-plugin-1.4.16

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

#make

#make install

Change the permissions on the plugins directory and the plugins to the nagios user.

nagios-plugin>#chown nagios.nagios /usr/local/nagios/

nagios-plugin>#chown nagios.nagios /usr/local/nagios/libexec/

Install xinetd package

nagios-plugin>#yum install xinetd

#cd . .

Download nrpe-2.13.tar.gz

#tar zxf nrpe-2.13.tar.gz

#cd nrpe-2.13

#./configure

#make all

#make install-plugin

#make install-daemon

#make install-daemon-config

#make install-xinetd

POST NRPE Configuration

Edit xinetd NRPE Entry:

Add nagios monitoring server to the “only_from” directive:

nrpe>#nano /etc/xinetd.d/nrpe

only_from = 127.0.0.1 192.168.145.132

EDIT SERVICES FILE ENTRY

Add entry for nrpe daemon:

nrpe>#nano /etc/services

go to bottom and write

nrpe 5666/tcp #NRPE

and save services

Restart xinetd and set to start at boot

nrpe>#chkconfig xinetd on

nrpe>#service xinetd start

#netstat –antp | grep 5666

If you can‟t see the service disable SE Linux

#nano /etc/selinux/config

Set to be disabled , if it is permissive - Restart the system

#service xinetd restart

#netstat –antp | grep 5666

Check NRPE daemon is functioning

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

NRPE v2.13

#/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/sda1

Disk OK – free space:/boot 167MB(93% inode=99%);

-w 20% (Warning)

-c 10% (Critical Warning)

-p /dev/sda1 (Parameter passing primary storage)

***NOW GO TO NAGIOS SERVER***

Download NRPE into the server, compile and configure NRPE

#tar xzf nrpe.tar.gz

#cd nrpe

nrpe>#./configure

nrpe>#make all

nrpe>#make install-plugin

CREATE NRPE COMMAND DEFINITION

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

nagios.

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

#######################################

# NRPE CHECK COMMAND

# Command to use NRPE to check remote host

######################################

define command{

command_name check_nrpe

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

}

#######################################

# CHECK WEBSITE RESPONSE

# Command to check public service

######################################

# „check_website_response‟ command definition

define command{

command_name check_website_response

command_line $USER1$/check_website_response.sh –u $ARG1$ -w $ARG2$ -c $ARG3$

}

And save the commands.cfg

Create new linux-box-remote object template file:

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

define host {

name linux-box-remote ; None 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 TIS-IT IS A TEMPLATE

}

define host{

use linux-box-remote ; Inherit default values from template

host_name LINUX1 ; Remote Linux Server

alias Fedora ; Alias Name

address 192.168.145.134 ; IP

}

define service{

use generic-service

host_name fc8

service_description CPULoad

check_command check_nrpe!check_load

}

Save linux-box-remote.cfg

ACTIVATE the linux-box-remote.cfg template

#nano /usr/local/nagios/etc/nagios.cfg

# Definitions for monitoring remote Linux machine

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

save nagios.cfg and exit

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

#service nagios restart

#service httpd restart

Open the browser http://localhost/nagios

Username: nagiosadmin

Password:Password123

Click on host

*** MONITORING PUBLICLY AVAILABLE SERVICES***

Examples of Pubic Services – HTTP , POP3 , IMAP etc

#cd /usr/local/nagios/libexec

(All the commands are stored in this path)

Copy check_website_response.sh to /usr/local/nagios/libexec

Add the following lines to nagios.cfg

# Definitions for monitoring Public Service

Cfg_file=/usr/local/nagios/etc/objects/publichost.cfg

Add the following to the /usr/local/nagios/etc/objects/commands.cfg

# „check_website_response‟ command definition

Define command {

Command_name check_website_response

Command_line $USER1$/check_website_response.sh –u $ARG1$ -w $ARG2$ -c

$ARG3$

}

#cd /usr/local/nagios/libexec

libexec>#ls –l check_website_response.sh

#chmod 755 check_website_response.sh

#./ check_website_response.sh

# check_website_response.sh –w 1000 –c 2000 –u http://192.168.1.181/

RESPONSE:OK

Create the file publichost.cfg under the path /usr/local/nagios/etc/objects

define host {

use generic-host ; Inherit default values from a template

host_name MYWEBSITE ; Website Name

max_check_attempts 3

contact_groups admins

}

define service {

host_name MYWEBSITE

service_description Website Response : www.mywebsite.in

check_command check_website_response!"http://192.168.1.181/"!1000!2000

max_check_attempts 5

check_interval 1

retry_interval 1

check_period 24x7

}

Save publichost.cfg

TESTING

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

#service nagios restart

Go to browser http://localhost/nagios

Username: nagiosadmin

Password:Password123

Click on Host and Services