app.pp
$color = 'blue'
$car = 'maruti'
node 'node1' {
include tomcat
}
node 'node2' {
$color = 'green'
include tomcat
}
Create tomcat::scope class
class tomcat::scope {
notify{"print the scope":
message => "
FAVOURITE COLOR : ${color}
FAVOURITE CAR : ${car}
"
}
}
Add this class to init.pp
class tomcat {
include tomcat::scope
include tomcat::install
include tomcat::config
include tomcat::service
}
Apply on both node1 and node2 and see the difference?
Question: Why does it print two different values?
create file: modules/tomcat/params.pp
class tomcat::params {
$color = 'white'
$car = 'figo'
}
Update tomcat::scope definition to inherit tomcat::params. Lets also define $color in this child class.
class tomcat::scope inherits tomcat::params{
$color = 'yellow'
notify{"print the scope":
message => "
FAVOURITE COLOR : ${color}
FAVOURITE CAR : ${car}
"
}
}
tomcat::params
class tomcat::params {
$color = 'white'
$car = 'figo'
$user = 'tomcat'
$group = 'tomcat'
$config_path = '/etc/tomcat/tomcat.conf'
$packages = [ 'tomcat', 'tomcat-webapps' ]
$service_name = 'tomcat'
$service_state = running
}
tomcat (init.pp)
class tomcat inherits tomcat::params{
include tomcat::scope
include tomcat::install
include tomcat::config
include tomcat::service
}
class tomcat::install
class tomcat::install inherits tomcat{
include java
package { $::tomcat::packages:
ensure => installed,
require => Package['epel-release']
}
}
class tomcat::config
class tomcat::config inherits tomcat{
file { $::tomcat::config_path:
source => 'puppet:///modules/tomcat/tomcat.conf',
owner => $::tomcat::user,
group => $::tomcat::group,
mode => '0644',
notify => Service['tomcat']
}
}
class tomcat::service
class tomcat::service inherits tomcat{
service { $::tomcat::service_name:
ensure => $::tomcat::service_state,
enable => true,
require => Class['tomcat::install'],
}
}
cd /workspace/code/environments/production/modules
puppet module generate --skip-interview user-base
mv /workspace/base.pp base/manifests/init.pp
Add class to modules/base/manifests/init.pp. Code for this class can be availed from https://gist.github.com/initcron/dd302fe9fabcc9a1af071394bf8e8d6a
Add the base class to one of the nodes, and see if you could apply
e.g. for node2 definition in app.pp
node 'node2' {
include base
$color = 'green'
include tomcat
}
Question : What happens when you apply this class on node2 by running puppet agent ??
Lets use params.pp for doing platform specific configurations,
class base::params {
case $::os['family'] {
'Debian': {
$ntp_service = 'ntp'
}
'RedHat': {
$ntp_service = 'ntpd'
}
}
}
And to use these params, we need to
- inherit base::params in base class (init.pp)
- parameterize the service name
Update init.pp with the above two changes. Here is the updated file for your reference https://gist.github.com/initcron/c8b6530dbae41c47c0d864d2a594844e
Lets also start using facts inside modules. To do this, lets create a file resource which generates /etc/motd and prints information about the system
Update modules/base/manifests/init.pp and add the following resource.
file { '/etc/motd':
ensure => file,
owner => 'root',
content => "
This server is a property of XYZ Inc.
SYSTEM INFO
============
Hostname : ${::fqdn}
IP Address : ${::ipaddress}
Memory : ${::memory['system']['total']}
Cores : ${::processors['count']}
OS : ${::os['distro']['description']}
"
}
Apply on all nodes and validate.