Dependency management with Puppet

Hi, I’m Richard Crowley

• Equal opportunity technology hater
• DevStructure’s operator and UNIX hacker

Installing Puppet

apt-get install build-essential \
    ruby ruby-dev rubygems
gem install puppet puppet-pip

• https://github.com/rcrowley/puppet-pip

Resources

• The smallest unit of configuration.
• Have a type, a name, and attributes.

Packages

• The obvious resource type.
• Abstract differences between
  package managers.

Package resources

package { "nginx":
    ensure => "0.7.67-3ubuntu1",
}

package {
    "mysql-python":
        ensure   => "1.2.3",
        provider => pip;
    "django":
        ensure   => "1.2.3",
        provider => pip;
}

A bug!

package {
    "mysql-python":
        ensure   => "1.2.3",
        provider => pip;
}

• Missing libmysqlclient-dev package which is needed to build mysql-python package.

Declare all dependencies

package {
    "libmysqlclient-dev":
        ensure => "5.1.49-1ubuntu8";
    "mysql-python":
        ensure   => "1.2.3",
        provider => pip;
}

Nondeterminism!

package {
    "libmysqlclient-dev":
        ensure => "5.1.49-1ubuntu8";
    "mysql-python":
        ensure   => "1.2.3",
        provider => pip;
}

Declare that dep

package {
    "libmysqlclient-dev":
        ensure => "5.1.49-1ubuntu8";
    "mysql-python":
        ensure   => "1.2.3",
        provider => pip,
        require  =>
            Package["libmysqlclient-dev"];
}

Realistic example

Running Puppet

# As root!
export GEMS="/usr/lib/ruby/gems/1.8/gems"
export RUBYLIB=$GEMS/"puppet-pip-0.0.1/lib"
puppet apply deps.pp

• Bring a new server up to speed.
• Incrementally manage your devbox.

• https://gist.github.com/668598

Thank you

• richard@devstructure.com or @rcrowley
• P.S. use DevStructure.