Why Puppet can require each package just once

configuration-managementpuppet

When defining dependencies in a class each Package can be globally defined just once. I have hierarchy of configuration and some packages should be installed on all machines (that goes to default configuration) but other should be installed only on some category of machines. How I am supposed to check whether that package is already on a machine when Puppet threat is as a duplicate declaration?

  Duplicate declaration: Package[wget] is already declared

should I use a function like this?

  if defined( Package[$package] ) {
    debug("$package already installed")
  } else {
    package { $package: ensure => $ensure }
  }

I would expect from configuration tool to deal whith this issue by default… am I missing something?

Best Answer

You can use the ensure_resource() from stdlib module:

$packages = $::osfamily ? {
    'Debian' => [ 'fcgiwrap', ],
    'RedHat' => [ 'spawn-fcgi', 'git' ],
}
ensure_resource('package', $packages, {'ensure' => 'present'})

So, say, if git is installed by some other class already, that would be skipped. You should not care of defining a package only once throughout the puppet configuration.

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