Nagios - Monitoring tool on CentOS 6.4 Script (1-4)

Nagios - Monitoring tool on CentOS 6.4

Part 1 Nagios Startup

Part 2 How to monitor Devices (1)

       Linux & Windows servers

Part 3 How to monitor Devices (2)

       Cisco Router & Web server

Part 4 Nagios Visualization 
       Nagiosgraph, NDOUtils with MySQL

Part 5 Nagios Notification & Security

Chapter 1 Network Monitoring Structure

Chapter 2  Testing Environment

1.NMS – Nagios (CentOS 6.4)

l IP Address: 192.168.80.6

l Hostname: client.chul.com

l Need to install and start Nagios service with Web server Apache

2. Managed Devices

1) Linux Server – 192.168.80.5 (CentOS 6.4)

l Need to install nagios-plugins & nrpe package and start nrpe with Xinetd

l Hostname: server.chul.com

2)Windows Server 2008 -  192.168.80.48

l Need to install NSClient++ file and start NSClient++ service

3) Cisco Router -  DHCP

l Configure snmp service and activate SNMP service

4) Apache web server on Linux server

 Need to start web server on Linux sever -  192.168.80.5

Chapter 3 Nagios Installation

1. Package installation

Download rpmforge-release and epel-release from rpmfind.net

# rpm –ivh rpmforge-*; rpm –ivh epel*

# rpm –qa | grep nagios

•      nagios-common-3.4.4-1.el6.i686

•      nagios-3.4.4-1.el6.i686

•      nagios-nrpe-2.14-1.el6.rf.i686

•      nagios-plugins-all-1.4.16-5.el6.i686

•      nagios-plugins-1.4.16-5.el6.i686

•      nagios-devel-3.4.4-1.el6.i686

•      nagios-nsca-2.7.2-4.el6.rf.i686

•      nagios-plugins-nrpe-2.14-1.el6.rf.i686

•      nagios-nsca-client-2.7.2-4.el6.rf.i686

2. Nagios Configuration

a. Modify username

# vi /etc/nagios/cgi.cfg                                

 authorized_for_all_services=nagios

 authorized_for_all_hosts=nagios

b. Nagios password file

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

   Access Control

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

3. Nagios files in /etc/nagios

nagios.cfg : the primary Nagios configuration file where lot of global parameters

cgi.cfg  :  configuration information for nagios web interface.

resource.cfg : some sensitive information (username, password etc.) to a plugin to

monitor a specific service

contacts.cfg:  all the contacts who needs to be notified

commands.cfg : all the commands to check services

timeperiods.cfg : define the timeperiods with time templetes

templates.cfg : multiple host or service definition similar to use all common templates

localhost.cfg : defines the monitoring for the local host as  sample configuration file

printer.cfg : sample config file for printer

switch.cfg : sample config file for switch

windows.cfg : sample config file for a windows machine

4. Access Nagios server

# service httpd restart ; nagios –v /etc/nagios/nagios.cfg

# service nagios restart ; tail –f /var/log/nagios/nagios.log

 http://localhost/nagios

Chapter 4  Managed Device - Linux Server

1.Linux Server Configuration

a. Structure of connection between NMS and Linux server

1) Nagios Server (check_nrpe) —> Remote host (NRPE deamon) —> check_disk(returns disk space usage)

2) Remote host (NRPE deamon) -> Nagios Server (check_nrpe) 

b. NRPE installation and startup

# yum install nagios-plugins-nrpe nagios-nrpe

# vi /etc/xinetd.d/nrpe

l disable = no

l only_from = 127.0.0.1 192.168.80.6

# service xinetd restart

# vi /etc/services

  nrpe                  5666/tcp     # NRPE

# netstat –at | grep nrpe

# /usr/lib/nagios/plugins/check_nrpe -H localhost

# vi /etc/nagios/nrpe.cfg                             // command checking

2. Nagios Server configuration

a. Installation and service checking

# yum install nagios-nrpe –y

# /usr/lib/nagios/plugins/check_nrpe -H 192.168.80.5

b. Creating server file

# cp localhost.cfg server.cfg

# vi /etc/nagios/objects/server.cfg                 //for host and service definition

§  define host{

use linux-server

host_name  server

    alias               Remote Host

    address         192.168.80.5

    contact_groups  admins

c. Adding server to nagios.cfg

# vi /etc/nagios/nagios.cfg

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

# nagios –v /etc/nagiios/nagios.cfg

# service nagios restart

# service httpd restart

d. Service Access

http://localhost/nagios/

Chapter 5  Managed Device –Windows Server

1. Structure of Windows host with Nagios server

a. Request: Nagios Server (check_nt) --> Remote host (NSClient++) —>                 USEDDISKSPACE
b. Reply: USEDDISKSPACE (returns disk space usage) ->Remote host (NSClient++)  ->Nagios Server (check_nt)

2. 4 steps to install nagios on remote Windows host

a. Install NSClient++ on the remote windows server

    http://sourceforge.net/projects/nscplus

b. Modify the NSClient++ Service

Control Panel -> Administrative Tools -> Services-> NSClientpp

c. Modify the nsclient.ini

§  Edit the C:\Program Files\NSClient++\nsclient.ini

§  allowed_hosts=192.168.80.6

§  port=12489

§  password=Password

d. Start the NSClient++ Service

Control Panel -> Administrative tools -> Services -> Select “NSClientpp (Nagios) 0.3.1.14 2008-03-12 w32″

3. 6 configuration steps on nagios monitoring server

a. Verify check_nt command and windows-server template

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

define command{

command_name    check_nt

command_line       $USER1$/check_nt -H $HOSTADDRESS$ -p 12489 -v $ARG1$ $ARG2$

}

# vi /etc/nagios/objects/templates.cfg                   // windows server template

b. Uncomment windows.cfg in /etc/nagios/nagios.cfg

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

c. Modify /etc/nagios/objects/windows.cfg

define host{

use                 windows-server              ; Inherit default values from a template

host_name           remote-windows-host      ; The name we're giving to this host

alias              Remote Windows Host     ; A longer name

address             192.168.80.48                  ; IP address of the remote windows host

}

d. Define windows services that should be monitored.

Modify /etc/nagios/objects/windows.cfg

Change host_name

e. Enable Password Protection (/etc/nagios/commands.cfg)

define command{

 command_name   check_nt

 command_line      $USER1$/check_nt -H $HOSTADDRESS$ -p 12489 -s Password -v $ARG1$ $ARG2$

}

f. Verify Configuration and Restart Nagios.

# nagios -v  /etc/nagios/nagios.cfg

# /usr/lib/nagios/plugins/check_nrpe –H 192.168.80.48

# service nagios restart

http://localhost/nagios

Chapter 6  Managed Device – Cisco Router

1.Cisco Router Configuration

Router(config)# access-list 5 permit 192.168.80.6

Router(config)# snmp-server community jeong ro 5

Router(config)# snmp-server host 192.168.80.6 jeong

Router(config)# snmp-server enable traps snmp linkdown linkup coldstart warmstart

In the Nagios server

# snmpget -v 1 -c jeong 192.168.80.11 SNMPv2-MIB::sysDescr.0

2. Nagios server configuration

a. Download and install the Nagios plugin from nagios.frank4dd.com/plugins/

# vi /usr/lib/nagios/plugins/contrib/check_snmp_patchlevel.pl

20 use lib "/usr/lib/nagios/plugins/" ;

#./check_snmp_patchlevel.pl -H 192.168.80.11 -g ios –C jeong

b. Configure the plugin and service in Nagios

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

define command{

  command_name    check_snmp_cisco_ios

  command_line    $USER1$/check_snmp_patchlevel.pl -H $HOSTADDRESS$ -g ios

-C $ARG1$

}

c. Configuring the Nagios Version Monitoring Service

# vi /etc/nagios/objects/router.cfg

# vi /etc/nagios/nagios.cfg

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

# nagios –v /etc/nagios/nagios.cfg

# service nagios restart

# service httpd restart

d. Test Router data on Nagios

http://localhost/nagios/

Chapter 7  Managed Device – Webserver

1.Load module in Apache webserver

# grep status /etc/httpd/conf/httpd.conf

LoadModule status_module modules/mod_status.so

ExtendedStatus On

 <Location /server-status>

 SetHandler server-status

 Order deny,allow

 Deny from all

 Allow from 192.168.80.6 127.0.0.1

 </Location>

# service httpd restart

2. Check nagios plugin for webserver in Nagios server

# /usr/lib/nagios/plugins/contrib/check_apachestatus.pl -H 192.168.80.5

3. Configuring the new Nagios Service

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

# check_apachestatus.pl -H  [-p ] [-t ] [-w  -c ] [-V]

define command{

  command_name    check_http_stat

  command_line    $USER1$/contrib/check_apachestatus.pl -H $HOSTADDRESS$ $ARG1$

}

# vi /etc/nagios/objects/webserver.cfg

# vi /etc/nagios/nagios.cfg

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

# nagiios –v /etc/nagios/nagios.cfg

# service nagios resart

http://localhost/nagios

Chapter 8 How to install Nagiosgraph

1.Install Pre packages

# yum install rrdtool perl-GD perl-CGI rrdtool-perl perl-Time-HiRes –y

2. Download and Install nagiosgraph from

http://sourceforge.net/projects/nagiosgraph/files/nagiosgraph

# cd nagiosgraph-1.4.4

# ./install.pl --check-prereq

# ./install.pl --install

3. Adding nagiosgraph to nagios.cfg

# vi /etc/nagios/nagios.cfg

4. Adding command to commands.cfg

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

# command to process nagios performance data for nagiosgraph

define command {

          command_name process-service-perfdata-for-nagiosgraph

          command_line /usr/local/nagiosgraph/bin/insert.pl

}

5. Copy nagiosgraph-apache

# cp /usr/local/nagiosgraph/etc/nagiosgraph-apache.conf /etc/httpd/conf.d/

6. Serive restart

# service httpd restart

# nagios –v /etc/nagios/nagios.cfg

# service nagios restart

7. Access nagiosgraph

http://localhost/nagiosgraph/cgi-bin/showconfig.cgi

8. Define service to the host file

# vi /etc/nagios/objects/server.cfg

define service {

          name nagiosgraph

          action_url /nagiosgraph/cgi-bin/show.cgi?host=$HOSTNAME$&serv ice=$SERVICEDESC$

          register 0

}

define service {

          use generic-service,nagiosgraph

          host_name  server

9. Service restart

# nagios –v /etc/nagios/nagios.cfg

# service nagios restart

10. Check nagiosgraph on Nagios

http://localhost/nagios

Click services

Chapter 9  NDOUtils with MySQL

1. NDOUtils

Have all of Nagios core’s configuration and data written into MySQL database

2. Packages installation

# yum install ndoutils ndoutils-mysql –y

3. Create database for ndoutils on MySQL

mysql> CREATE DATABASE nagios;

mysql> CREATE USER 'ndo'@'localhost' IDENTIFIED BY ‘ndo’;

mysql> GRANT ALL ON nagios.* TO 'ndo'@'localhost';

mysql> flush privileges;

# cd /usr/share/doc/ndoutils-mysql-1.4/db

# perl installdb -u ndo -p ndo -h localhost -d nagios       //load nagios schema

4. Edit nagios.cfg file

# vi /etc/nagios/nagios.cfg

221 event_broker_options=-1

222 broker_module=/usr/lib/nagios/brokers/ndomod.so config_file=/etc/nagios/ndomod.cfg

5. Edit ndo2db.cfg

# vi /etc/nagios/ndo2db.cfg

•      db_host=localhost

•      db_port=3306 .

•      db_name=nagios

•      db_user=ndo

 db_pass=ndo

6. Start ndo service

# service ndo2db start

# ps –ef | grep ndo2db

# nagios –v /etc/nagios/nagios.cfg

# service nagios restart

7. Nagios data on MySQL

# mysql –u ndo –p  –D nagios

a. Retrieve nagios_services table

mysql> select count(1) from nagios_services;

b. Retrieve the content and date/time of the latest ten notifications:

mysql> select start_time, long_output from nagios_notifications ORDER BY start_time DESC LIMIT 10;

c. Retrieve the content and date/time of the latest ten host or service comments:

mysql> select entry_time, comment_data from nagios_commenthistory ORDER BY entry_time DESC LIMIT 10;

d. Count the number of hosts currently in the OK state:

mysql> select COUNT(1) from nagios_hoststatus WHERE current_state=0;