How to create array of arrays from hiera in puppet

The natural way to represent your data in a programming language would be a hash like this:

$users = {
  elion => 'El Lion',
  azee  => 'Avery Zee',
  root  => 'Rooty Root,
}

While doing that in Puppet is possible, I've found it's best to decide what a resource definition for a single entry would be and then structure the hash as something you could pass to create_resources(). In this case, that would mean something like this:

define student ($full_name) {
  notify { "user ${title}":
    message => "username: ${title}\n",
  }
  notify { "fullname ${title}":
    message => "fullname: ${full_name}\n",
  }
  exec { "finger ${title}":
    command   => "/usr/bin/finger ${title}",
    logoutput => true,
  }
}

$users = {
  elion => { full_name => 'El Lion'   },
  azee  => { full_name => 'Avery Zee' },
  root  => { full_name => 'Rooty Root },
}

create_resources(student, $users)

However, as Ger notes, you'll be best off if you use Hiera. Hiera lets you separate your code (the manifest definitions) from your data (in this case, the particular names of the students). In full, here's what I would do for your setup:

• Put the student data in a hiera file. You can use JSON or YAML; I like YAML. It would be something like this:

  classroom::users:
    elion:
      full_name: El Lion
    azee:
      full_name: Avery Zee
    root:
      full_name: Rooty Root
  

• Define a resource type for students and put it in classroom/manifests/student.pp in Puppet's $modulepath. It would look like the student resource type above, but would be named classroom::student.

• Define a classroom class in classroom/manifests/init.pp with the following content:

  class classroom (
    $users = hiera('classroom::users', undef),
  ) {
    create_resources(classroom::student, $users)
  }
  

If you're using Puppet 3.x, the hiera() call in the class parameters is redundant, but you need it if you're still on Puppet 2.7.

Finally I found this was a variable scope problem, the correct init.pp should be:

class install(
  $common_instances = hiera_array('common_instances'),
  $common_instanceconfig = hiera_array('common_instanceconfigs'),
) 
{
  define instances (
  $common_instanceconfig
  ) {   

  common { $common_instances[0]: 
    name       => $title,
    path       => $common_instanceconfig[0],
    version    => $common_instanceconfig[1],
    files      => $common_instanceconfig[2],
    pre        => $common_instanceconfig[3],
    after      => $common_instanceconfig[4],
    properties => $common_instanceconfig[5],
    require    => $common_instanceconfig[$title]['require'] ,
   }   
  }

  instances {$common_instances: 
    common_instanceconfig => $common_instanceconfig
  }

}