Note: This article based on Part 1 – Part 3 of my puppet articles. Please read them first !

Factor allows to you add information from your nodes to your puppet configuration.
Facts are available as variables. Execute the “facter” command and you get a full list of facts an their values:

sebastian@pc1:~$ facter
architecture => i386
domain => domain.local
facterversion => 1.5.1
fqdn => pc1.domain.local
hardwaremodel => i686
hostname => pc1
interfaces => eth0
ipaddress => 192.168.0.2
ipaddress_eth0 => 192.168.0.2
kernel => Linux
kernelrelease => 2.6.28-11-server
kernelversion => 2.6.28
lsbdistcodename => jaunty
lsbdistdescription => Ubuntu 9.04
lsbdistid => Ubuntu
lsbdistrelease => 9.04
macaddress => 00:0c:29:7a:37:37
macaddress_eth0 => 00:0c:29:7a:37:37
memoryfree => 417.25 MB
memorysize => 497.37 MB
netmask => 255.255.255.0
netmask_eth0 => 255.255.255.0
operatingsystem => Ubuntu
operatingsystemrelease => 9.04
processor0 => Intel(R) Xeon(TM) CPU 2.80GHz
processorcount => 1
ps => ps -ef
puppetversion => 0.24.5
rubysitedir => /usr/local/lib/site_ruby/1.8
rubyversion => 1.8.7
swapfree => 883.99 MB
swapsize => 883.99 MB
virtual => vmware

You see that my “pc1″ is a 32-Bit virtual machine with Ubuntu 9.04. Now we want to extend our “baseclass template” to install the vmware-tools on all virtual machines.

Edit “/etc/puppet/manifests/templates.pp”:

#
# templates.pp
#

class baseclass {
include user::admins
include munin::client
include ntp

if $virtual == "vmware" {
include vmware::client
}
case $virtual {
vmware: { include vmware::client }
}

}

Create vmware module:

mkdir -p /etc/puppet/modules/vmware/manifests/

Create “/etc/puppet/modules/vmware/manifests/init.pp” file:

#
# init.pp
#

class vmware{

}

Create “/etc/puppet/modules/vmware/manifests/client.pp” file:

#
# client.pp
#

class vmware::client inherits vmware{

package { open-vm-tools: ensure => installed }

}

Note: This is a simple example. If you have more than one operating system in your environment, you need the “operatingsystem” variable for a second condition.
http://reductivelabs.com/trac/puppet/wiki/LanguageTutorial#conditionals

Custom Facts

You can also define your own facts in puppet.

http://reductivelabs.com/trac/puppet/wiki/AddingFacts