On this post I will present couple of examples about Puppet’s Class and Module sections. This is all tested on Ubuntu 12.04 and continues my Puppet series where I am going through all the necessary and important aspects of Linux’s Puppet software.
Class
I will continue using the same example of Apache2 I have used during my last posts about Puppet.
In order to make classes work we need to apply them a little bit differently than normal manifests. With puppet apply --verbose apacheclassname.pp you can use the class written below.
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class apacheclassname { package { 'apache2': provider=>'apt', ensure=>'installed' } notify { 'Apache2 is installed.': } service { 'apache2': ensure=>'running' } notify { 'Apache2 is running.': } } #Remember to declare the class below class {'apacheclassname': } |
Module
Modules are used by Puppet to autoload manifests, so you can use classes stored in a module from anywhere. Now we need to take our just created class into a module. Modules file and folder structure is at its simplest like this: modules/modulename/manifests in this folder you have init.pp which will be ran everytime you do something with the module.
Place the code below to this init.pp file in modules/apache/manifests/ and run it with puppet apply --modulepath PATHtoMODULeDIRECTORY -e "include apacheclassname"
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class apacheclassname { package { 'apache2': provider=>'apt', ensure=>'installed' } notify { 'Apache2 is installed.': } service { 'apache2': ensure=>'running' } notify { 'Apache2 is running.': } } #Remember NOT to declare the class in here |
Here is another module about file permissions which changes the default www-directory to be used www-data user. This should go to modules/wwwdir/init.pp and you can run it with puppet apply --modulepath PATHtoMODULeDIRECTORY -e "include wwwdir"
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class wwwdir { file{ '/var/www': ensure=>'directory', owner=>'www-data', group=>'www-data', mode=>'664', } } |
There was some example classes and modules. I hope they helped you out!