Flush Your Local DNS Cache

 

Windows Vista/Windows 7:
ipconfig /flushdns
Successfully flushed the DNS Resolver Cache.

Windows XP
ipconfig /flushdns
Successfully flushed the DNS Resolver Cache.

Mac OS X 10.5.2 and above
dscacheutil -flushcache

Mac OS X 10.5.1 and below
Click on the Finder icon in your dock. Open your Applications folder.
Inside the Applications folder, click on Utilities and then Terminal.
Type the following command in the Terminal window and press Enter:
lookupd -flushcache

Linux

nscd -i hosts
– Clear local DNS cache for current user.
nscd -I hosts
– Clear local DNS cache for all users.

Creating a custom Nagios function

Nagios Exit Codes
Exit Code Status
0 OK
1 WARNING
2 CRITICAL
3 UNKNOWN
Create the Script to be added as the Plugin

#!/bin/bash
used_space=`df -h / | grep -v Filesy | awk '{print $5}' | sed 's/%//g'`
case $used_space in
[1-84]*)
echo "OK - $used_space% of disk space used."
exit 0
;;
[85]*)
echo "WARNING - $used_space% of disk space used."
exit 1
;;
[86-100]*)
echo "CRITICAL - $used_space% of disk space used."
exit 2
;;
*)
echo "UNKNOWN - $used_space% of disk space used."
exit 3
;;
esac

try to put the script in same plugin directory with the other ones
/usr/lib/nagios/plugins/

make it executable
Add Your New Command to Nagios Checks on Nagios Monitoring Server

Define new command in /etc/nagios/objects/commands.cfg
define command{
command_name usedspace_bash
command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c usedspace_bash
}
Add Your Script to NRPE configuration on client host
command[usedspace_bash]=/usr/lib/nagios/plugins/usedspace.sh

 

adding to configuration
/etc/nagios/servers/<name-0f-config>.cfg
define service {
use generic-service
host_name Hostname
service_description Custom Disk Checker In Bash
check_command usedspace_bash
}

 

 

Adding ESXI to Nagios

yum install perl-Pod-Perldoc perl-CPAN openssl-devel
# wget http://dl.fedoraproject.org/pub/epel/6/i386/perl-Nagios-Plugin-0.35-1.el6.noarch.rpm
# wget http://mirror.centos.org/centos/6/os/i386/Packages/perl-Config-Tiny-2.12-7.1.el6.noarch.rpm
# wget http://mirror.centos.org/centos/6/os/i386/Packages/perl-Params-Validate-0.92-3.el6.i686.rpm
# rpm -ivh perl-Nagios-Plugin-0.35-1.el6.noarch.rpm perl-Config-Tiny-2.12-7.1.el6.noarch.rpm perl-Params-Validate-0.92-3.el6.i686.rpm
# cd /root
# tar xvzf VMware-vSphere-Perl-SDK-4.1.0-254719.i386.tar.gz
# cd vmware-vsphere-cli-distrib/
# ./vmware-install.pl

# cd /usr/lib/nagios/plugins/
Download check_esx3.pl and make it executable
http://exchange.nagios.org/components/com_mtree/attachment.php?link_id=2154&cf_id=29
chmod +x check_esx3.pl


vim /usr/local/nagios/etc/objects/vmware.cfg
First define all your hosts as shown below

# Host esx01
define host{
use vmware-server
host_name esxi01
alias VMWare ESXi 01
address IP Address
}
define host{
use vmware-server
host_name esxi02
alias VMWare ESXi 02
address IP Address
}
# Similarly you can define all the hosts

# Now define a hostgroup for your Esxi Hosts:

define hostgroup{
hostgroup_name Esxi-Servers ; The name of the hostgroup

alias Vmware Servers ; Long name of the group

members esxi01,esxi02
}

# Now create the service definition as shown below
# check cpu
define service{
use generic-service
host_name esxi01
service_description ESXi CPU Load
check_command check_esx_cpu!80!90
}

# check memory usage
define service{
use generic-service
host_name esxi01
service_description ESXi Memory usage
check_command check_esx_mem!80!90
}

# check net
define service{
use generic-service
host_name esxi01
service_description ESXi Network usage
check_command check_esx_net!102400!204800
}

# check runtime status
define service{
use generic-service
host_name esxi01
service_description ESXi Runtime status
check_command check_esx_runtime
}

# check io read
define service{
use generic-service
host_name esxi01
service_description ESXi IO read
check_command check_esx_ioread!40!90
}

# check io write
define service{
use generic-service
host_name esxi01
service_description ESXi IO write
check_command check_esx_iowrite!40!90
}

Define the commands related to ESXi in the /usr/local/nagios/etc/objects/command.cfg file

vim /usr/local/nagios/etc/objects/commands.cfg
# check vmware esxi machine
# check cpu
define command{
command_name check_esx_cpu
command_line $USER1$/check_esx -H $HOSTADDRESS$ -u $USER11$ -p $USER12$ -l cpu -s usage -w $ARG1$ -c $ARG2$
}

# check memory usage
define command{
command_name check_esx_mem
command_line $USER1$/check_esx -H $HOSTADDRESS$ -u $USER11$ -p $USER12$ -l mem -s usage -w $ARG1$ -c $ARG2$
}

# check net usage
define command{
command_name check_esx_net
command_line $USER1$/check_esx -H $HOSTADDRESS$ -u $USER11$ -p $USER12$ -l net -s usage -w $ARG1$ -c $ARG2$
}

# check runtime status
define command{
command_name check_esx_runtime
command_line $USER1$/check_esx -H $HOSTADDRESS$ -u $USER11$ -p $USER12$ -l runtime -s status
}

# check io read
define command{
command_name check_esx_ioread
command_line $USER1$/check_esx -H $HOSTADDRESS$ -u $USER11$ -p $USER12$ -l io -s read -w $ARG1$ -c $ARG2$
}

# check io write
define command{
command_name check_esx_iowrite
command_line $USER1$/check_esx -H $HOSTADDRESS$ -u $USER11$ -p $USER12$ -l io -s write -w $ARG1$ -c $ARG2$
}

Adding configuration to nagios

vim /usr/local/nagios/etc/nagios.cfg
cfg_file=/usr/local/nagios/etc/objects/vmware.cfg