AHMED ZBYR

AHMED ZBYR

Biker, EV Enthusiast

Nagios monitors your entire IT infrastructure to ensure systems, applications, services, and business processes are functioning properly. In the event of a failure, Nagios can alert technical staff of the problem, allowing them to begin remediation processes before outages affect business processes, end-users, or customers.

Intro from : https://www.nagios.org/about/

Installation Nagios XI

Here is the link to [Nagios XI 5.2.9](https://assets.nagios.com/downloads/nagiosxi/5/xi-5.2.9.tar.gz

Installation for Nagios for most of the cases is quite staight forward.

tar xzf xi*.tar.gz
cd nagiosxi
./fullinstall

And the script will do all the hardward and we are done. Once install is complete, visit the URL displayed to complete the install

Running Full Install

Running full install

Installation Complete

Installation Complete

Initial Configuration

Initial configuration done

Configuration

Checking if NRDS is working fine.

Go to the URL http://nagios-server/nrdp on the nagios server. [NRDP - Nagios Remote Data processor.]

submit a query

This is the response from the server.

Response

These submitted parameters will show up in the Unconfigured Objects page, which can be added directly.

Unconfigured Objects

Creating an inbound configuration.

For servers to send-in their monitoring data, we need to create tokens so that the servers can authenticate themself.

Creating inbound config.

NRDP Configuration

Inbound NRDP Configuration

NSCA Configuration (Optional - Only if you are using this - Not recommended to use this as this is very old and not very reliable)

Inbound NSCA Configuration

Creating NRDP Configuration for Windows and Linux.

Creating Config for Linux

Config for Linux

Selecting Token and add config name

setting up info

Configuration Complete

Config Complete

Now we are ready to setup the Clients.

Once the client starts sending results, if the host/service has not been configured yet it will be found in Unconfigured Objects and can easily be added to the monitoring config.

Monitoring using NRDS on Linux.

Config Complete

The following commands can be run as root on all clients that will use the new_linux_config config. The install process will perform the following operations:

  • Install NRDS client
  • Add a nagios user and group
  • Add cron job to process checks
  • Download plugins from the NRDP server

There are 2 items you need to modify below, HOSTNAME and INTERVAL.

  • HOSTNAME - The name the client will send to the Nagios server as the host.
  • INTERVAL - The frequency in minutes that you want the checks to be run. (1-59)

Below are the commands.

cd /tmp

Get the tar file from the server.

wget -O new_linux_config.tar.gz "http://<nagios_server_url>/nrdp/?cmd=nrdsgetclient&token=hardtoguess&configname=new_linux_config"

Unzip and install.

gunzip -c new_linux_config.tar.gz | tar xf -
cd clients
./installnrds [HOSTNAME] [INTERVAL_IN_MINUTES]

Command

./installnrds linux-server 5

This install the client and setup a crontab to send the parameters to the server.
When the client linux-server sends the data you will see the details on the Unconfigured Objects page.

Select the parameters and add it to the nagios monitoring. It would look similar to the page below.

nrds_testing

Monitoring using NRDS on windows.

Download the executable from the link in the image

Config Complete

Agreement

Agreement

Configure Server Name and Interval to send the data

Config

Create ini file and and setup scheduler task

ini file

Install

Install

Once the client starts sending results, if the host/service has not been configured yet it will be found in Unconfigured Objects and can easily be added to the monitoring config. Example below.

testing

Select the parameters and add it to the nagios monitoring. It would look similar to the page below.

Creating Groups for user to monitor specific servers.

Below are the steps to create a user groups.

  1. Create a contact file in /usr/local/nagios/etc/static
  2. Create a contactgroup file in /usr/local/nagios/etc/static
  3. Create a host file which binds the contact group.
  4. And restart nagios service.

What are we trying to do.

  1. On the nagios server we have 2 server which we monitor, A linux server and a windows server.
  2. We want to make sure that the windows server is monitored by the windows admin team.
  3. We will create a group and a user which can only see window server on the monitoring console.
  4. This will help create set of groups, who can monitor only their servers which they are responsible for.

Location of all the files on the server.

┌─[zahmed][localhost][~]
└─▪ cd /usr/local/nagios/etc/
┌─[zahmed][localhost][/usr/local/nagios/etc]
└─▪ ls
cgi.cfg               hosttemplates.cfg  servicedependencies.cfg
commands.cfg          import             serviceescalations.cfg
contactgroups.cfg     nagios.cfg         serviceextinfo.cfg
contacts.cfg          ndo2db.cfg         servicegroups.cfg
contacttemplates.cfg  ndomod.cfg         services
hostdependencies.cfg  nrpe.cfg           servicetemplates.cfg
hostescalations.cfg   nsca.cfg           static
hostextinfo.cfg       pnp                timeperiods.cfg
hostgroups.cfg        resource.cfg
hosts                 send_nsca.cfg
┌─[zahmed][localhost][/usr/local/nagios/etc]
└─▪

Creating a contact with windowsnagiosadmin user.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ cat windows-server-contact.cfg
define contact {
        contact_name                            windowsnagiosadmin
        alias                                   Windows Nagios Administrator
        host_notification_period                nagiosadmin_notification_times
        service_notification_period             nagiosadmin_notification_times
        host_notification_options               d,u,r,f,s
        service_notification_options            w,u,c,r,f,s
        host_notification_commands              xi_host_notification_handler
        service_notification_commands           xi_service_notification_handler
        email                                   ahmed@gmail.com
        #use                                     xi_contact_generic
}

Create a contactgroup and add the above windowsnagiosadmin user as a member.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ cat windows-server-contactgroup.cfg
define contactgroup {
    contactgroup_name                   windowsadmins
    alias                               Windows Nagios Admin Group
    members                             windowsnagiosadmin
}

Now finally create a host configuration which is tied to the windowsadmins contact group above.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ cat nagios-test-windows.cfg
define host {
        host_name                       nagios-test-wındows
        use                             xiwizard_passive_host
        address                         nagios-test-wındows
        max_check_attempts              5
        check_interval                  5
        retry_interval                  1
        check_period                    xi_timeperiod_24x7
        contact_groups                 windowsadmins
        notification_interval           60
        notification_period             xi_timeperiod_24x7
        stalking_options                n
        icon_image                      passiveobject.png
        statusmap_image                 passiveobject.png
        _xiwizard                       passiveobject
        register                        1
        }
┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪

Files in static directory.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ ls -l
total 24
-rwxrwxr-x 1 apache nagios  661 Aug 12 11:27 windows-server-contact.cfg
-rwxrwxr-x 1 apache nagios  211 Aug 12 11:57 windows-server-contactgroup.cfg
-rwxrwxr-x 1 apache nagios  802 Aug 12 11:39 nagios-test-windows.cfg
-rwxrwxr-x 1 apache nagios  878 Jun 14 20:43 xiobjects.cfg
-rwxrwxr-x 1 apache nagios 4002 Jun 14 20:43 xitemplates.cfg
-rwxrwxr-x 1 apache nagios    0 Jun 14 20:43 xitest.cfg
-rwxr-xr-x 1 root   nagios  649 Aug 12 11:59 zahmedcontact.cfg

Check Nagios config.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ sudo service nagios checkconfig
[sudo] password for zahmed:
Running configuration check...
 OK.

All OK, then restart nagios

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ sudo service nagios restart
Running configuration check...
Stopping nagios:. done.
Starting nagios: done.

Finally create a user on nagios which matches our configuration windowsnagiosadmin.

Creating a windowsnagiosadmin user.

windows_user

Host when we login as nagiosadmin

login

Hosts when we login as windowsnagiosadmin

loggedin

Installation and Configuring NSClient++ for Windows.

Download and install NSClient++ on the windows server. https://nsclient.org/download/

First Installing NSClient++

install

Configure NSClient

Update the allowed_hosts and password. And make sure to use check_nt

config

Install Complete

complete

Check service is running

service check

Configuring on the nagios server.

We need to create couple of configurations for the first time a windows machine is setup. After that all we have to do is add the hosts configuration. Everything else will be the same. (Unless we change the password on few of the windows machine then we have to update / create new command configuration)

  1. Create a host configuration.
  2. Add services configuration which will define what we want to monitor.
  3. Create a command configuration.

First lets create a file new-windows-test.cfg in /usr/local/nagios/etc/static directory.

We will be adding the host and service configuration into the same file.

NOTE : check_command in the service definitions should be same as the command_name in commands configuration. Example: check_nt_test

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ cat new-windows-test.cfg
define host{
	use		            windows-server	; Inherit default values from a Windows server template (make sure you keep this line!)
	host_name	        winservertest
	alias		        My Windows Server
	address		        172.2.2.35
    max_check_attempts  10
    check_interval      5
    retry_interval      1
    check_period        24x7
    contacts            nagiosadmin
    notification_interval   30
    notification_period     24x7
    notification_options    d,r
    register                1
	}
    
define service{
	use		            generic-service
	host_name		    winserver
	service_description	NSClient++ Version
	check_command		check_nt_test!CLIENTVERSION
	}
    
define service{
	use			        generic-service
	host_name			winserver
	service_description	Uptime
	check_command		check_nt_test!UPTIME
	}

define service{
	use			        generic-service
	host_name			winserver
	service_description	CPU Load
	check_command		check_nt_test!CPULOAD!-l 5,80,90
	}

define service{
	use			        generic-service
	host_name			winserver
	service_description	Memory Usage
	check_command		check_nt_test!MEMUSE!-w 80 -c 90
	}

define service{
	use			        generic-service
	host_name			winserver
	service_description	C:\ Drive Space
	check_command		check_nt_test!USEDDISKSPACE!-l c -w 80 -c 90
	}
    
define service{
	use			        generic-service
	host_name			winserver
	service_description	W3SVC
	check_command		check_nt_test!SERVICESTATE!-d SHOWALL -l W3SVC
	}

define service{
	use			        generic-service
	host_name			winserver
	service_description	Explorer
	check_command		check_nt_test!PROCSTATE!-d SHOWALL -l Explorer.exe
	}

First lets create a file new-windows-test-command.cfg, update the password -s below with the password we created on the windows machine. [Check image above]

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ cat new-windows-test-command.cfg
define command{
        command_name    check_nt_test
        command_line    $USER1$/check_nt -H $HOSTADDRESS$ -p 12489 -s nagios123 -v $ARG1$ $ARG2$
        }

After we have configured new files.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ ls -l new*
-rw-r--r-- 1 apache nagios 1301 Aug 15 11:07 new-windows-test.cfg
-rw-r--r-- 1 apache nagios  134 Aug 15 10:57 new-windows-test-command.cfg

Check if our configuration is fine.

┌─[zahmed][localhost][/usr/local/nagios/etc/static]
└─▪ sudo service nagios checkconfig
[sudo] password for zahmed:
Running configuration check...
 OK.

Great!!, we have not errors, now we can restart nagios.

┌─[zahmed][localhost][/usr/local/nagios/etc]
└─▪ sudo service nagios restart
Running configuration check...
Stopping nagios:. done.
Starting nagios: done.

Restart complete and we are done.

Checking the new host on the dashboard.

New host winservertest is added to the dashboard.

service check

We are receiving monitoring data as well.

service check

Performance data.

service check

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