Nagios Add Remote Host - CentOS 7

### Client Side Details & Configuration             

### OS - CentOS 7 64bit                

### IP - 172.17.25.100                 

### Hostname - webserver.example.com

  

Step 1:

Setup NRPE Service on Linux Host

vi /etc/hosts

Install Package & Plugin

yum install epel*

yum install nrpe nagios-plugins*                               # CentOS/RHEL/Fedora

OR

apt-get install nagios-nrpe-server nagios-plugins     # Debian/Ubuntu/LinuxMint

Step 2:

Configure NRPE

   vi /etc/nagios/nrpe.cfg

#Add Nagios Server IP

allowed_hosts=127.0.0.1, 172.17.20.100

   

#Allow Argument

# Values: 0=do not allow arguments, 1=allow command arguments

dont_blame_nrpe=1

Step 3:

Add Command

# The following examples use hard-coded command arguments...

command[check_users]=/usr/lib64/nagios/plugins/check_users -w 5 -c 10

command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20

command[check_root]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /dev/mapper/centos-root

command[check_total_procs]=/usr/lib64/nagios/plugins/check_procs -w 150 -c 200

command[check_swap]=/usr/lib64/nagios/plugins/check_swap -w 20 -c 10

command[check_http]=/usr/lib64/nagios/plugins/check_http -H 172.17.20.103

Step 4:

Restart Service

systemctl restart nrpe.service
or
service nrpe restart
or
sudo /etc/init.d/nagios-nrpe-server restart 

## Allow on Firewalld

firewall-cmd --add-port=5666/tcp --permanent

firewall-cmd --reload

### Server Side Configuration ######

### OS - CentOS 7 64bit       ######

### IP - 172.17.25.200       #####

### Hostname - nagios.linuxtopic.com ####

Step 5:

## Install nrpe

yum install openssl-devel xinetd unzip

# Download nrpe

cd /tmp

curl -L -O http://downloads.sourceforge.net/project/nagios/nrpe-2.x/nrpe-2.15/nrpe-2.15.tar.gz

tar xvf nrpe-2.15.tar.gz

cd nrpe-2.15

./configure --enable-command-args --with-nagios-user=nagios --with-nagios-group=nagiosgroup --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib/x86_64-linux-gnu

make all
make install
make install-xinetd
make install-daemon-config

# Test nrpe client

telnet <client ip> 5666

/usr/local/nagios/libexec/check_nrpe -H 172.17.25.100

Step 6:

 # Configure HOST

vi /usr/local/nagios/etc/servers/webserver.linuxtopic.cfg

## Host Details ###

define host {

       use                                   linux-server

       host_name                       webserver.linuxtopic.com

       alias                                 MyWeb

       address                           172.17.20.103

       max_check_attempts       10

       check_period                    24x7

       notification_interval           10       # Notification

       notification_period             24x7

}

# Define Group

define hostgroup{

       hostgroup_name             Webserver_Group

       alias                                 MyWebserver

#     members                        172.17.20.103

       }

####

# Check Ping

define service {

       use                                 generic-service

       host_name                       webserver.linuxtopic.com

       service_description             PING

       check_command                   check_ping!100.0,20%!500.0,60%

       check_interval                  1    # 1 min

       retry_interval                  1    # 1 min

}

# Define a service to check the load on the local machine.

define service{

       use                                local-service

       host_name                       webserver.linuxtopic.com

       service_description             Current Load

       check_command                   check_nrpe!check_load!15.0,12.0,10.0!20.0,18.0,15.0

       check_interval                  1

       retry_interval                  1

       }

# Check Users

define service{

       use                           generic-service

       host_name                 webserver.linuxtopic.com

       service_description        Current Users

       check_command            check_nrpe!check_users

       check_interval               1

       retry_interval               1

}

# Check Process

define service{

       use                                 local-service

       host_name                       webserver.linuxtopic.com

       service_description             Total Processes

       check_command                   check_nrpe!check_total_procs!250!400!RSZDT

       check_interval                  1

       retry_interval                  1

}

# Check Root Part.

define service{

       use                               local-service

       host_name                       webserver.linuxtopic.com

       service_description             Disk-Root-Partition

       check_command                   check_nrpe!check_root!10%!5%!/

       check_interval                  1

       retry_interval                  1

}

# Define a service to check the swap usage the local machine.

# Critical if less than 10% of swap is free, warning if less than 20% is free

define service{

       use                                 local-service

       host_name                       webserver.linuxtopic.com

       service_description             Disk-Swap-Partition

       check_command                   check_nrpe!check_swap!20!10

       check_interval                  1

       retry_interval                  1

}

## Check HTTP Server

define service{

       use                                local-service

       host_name                       webserver.linuxtopic.com

       service_description             WEB-HTTP

       check_command                   check_nrpe!check_http

       check_interval                  1

       retry_interval                  1

}

Part 1: Nagios Core 4.X configuration in Linux

Part 2: Add Remote hosts and service in Nagios

Part 3: Monitor MySQL/MariaDB Using check_mysql Plugin

Part 4: Monitor Tomcat using check_tomcat Plugin