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Tombart
Asked: 2013-03-11 08:57:06 +0800 CST

Why Puppet can require each package just once?

  • 772

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?

puppet

2 Answers

  1. 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.

    • 7

  2. When you have duplicate packages, that's one way of dealing with it. The other way is to avoid the problem in the first place by using virtual resources:

    Declaring a virtual resource

    class packages {
  @package {
    ['cryptsetup-bin',
     'cryptsetup',
     'cifs-utils',
     'e2fsprogs',
     'libmysql-ruby',
     'parted',
     'pigz',
      'sshfs' ]:
        ensure => present,
    }
}

    Realizing a virtual resource (you can realize resources multiple times):

    include packages
realize Package['pigz']

    Another approach is to separate out the duplicated code into another class - i.e. a 'wget' class.

    Reference: Virtual Resource Puppet Doc

    • 5