Drawing dependency graphs

Dependencies can get complicated quickly, and it's easy to end up with a circular dependency (where A depends on B, which depends on A) that will cause Puppet to complain and stop working. Fortunately, Puppet's --graph option makes it easy to generate a diagram of your resources and the dependencies between them, which can be a big help in fixing such problems.

Getting ready…

Install the graphviz package for viewing the diagram files:

ubuntu@cookbook:~/puppet$ sudo apt-get install graphviz

How to do it…

Follow these steps to generate a dependency graph for your manifest:

1. Create the directories for a new admin module:

   ubuntu@cookbook:~/puppet$ mkdir modules/admin
   ubuntu@cookbook:~/puppet$ mkdir modules/admin/manifests
   ubuntu@cookbook:~/puppet$ mkdir modules/admin/files
   

2. Create the file modules/admin/manifests/ntp.pp with the following code containing a deliberate circular dependency (can you spot it?):

   # Manage NTP
   class admin::ntp {
     package { 'ntp':
       ensure  =&gt...