Introduction to Hiera &Basic Hiera Data Structures

David Kramer, RHCA

Sr. DevOps Manager

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Introduction to Hiera Agenda

• Quick intro about myself• What is this presentation and what isn’t it?• Overview of Puppet • Overview of Hiera• Overview of Hiera Data Structures• Tying it all together

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Overview of Puppet

• What is Puppet?– Should I mention facter?

• How do we manage nodes in Puppet?– Every node always gets a node object

• Nodes.pp• ENC

– Node_terminus

• Hiera

• Common question Im asked, can you have multiple ENC’s? Yes you can!

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What is Hiera?

• Hiera is a Key/Pair lookup tool• Provides an Environment Hierarchy within

your data roles• Reduces data repetition

– Write data for most scenarios– Allows you to focus on difference data!

• Allows you to specify node specific data– Provides Hierarchical Overriding

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Brief Installation Overview of Hiera

• Package Info– Hiera Gem– Puppet 2.7.x needs hiera-puppet package installed.– Puppet 3.0+ does not need hiera-puppet, hiera is

native!

• /etc/puppet/hiera.yaml– Role Hierarchy definitions

• Modify your sites.pp to be hiera aware!– classes: - hiera_include('classes')– parameterized_classes: –

hiera_hash(‘parameterized_classes’ )

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Walking thru the hiera.yaml

• :backends:– Yaml– Json

• :datadir:– :yaml /etc/puppet/hieradata

• :gpg:– Tired of storing secret information in the clear?

• :hierarchy:– %{::clientcert}– roles/%{role}

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Hierarchy for your Environments

• Meta Data, Meta Data, Meta Data– Custom Facts using Facter.add

• This is all up to you!!• Some Jivin examples:

– Data Center– Deployment Environment –Your SDLC!– Roles

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Overview of Hiera Data Structures

• Hiera Variable– hiera(‘variable name’,’empty’)

• Hiera Array– hiera_array( ‘array name’, ‘empty’)

• Hiera Hashes– hiera_hash(‘hash name’, ‘empty’)

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Yaml Data Structure Examples

• Yaml Variable:

• Yaml Array:

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Yaml Data Structure Examples

• Yaml Hash:

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Hooking your Yaml into your Puppet

• Tying all of this together by making your Puppet Class Hiera aware:

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Questions?

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http://docs.puppetlabs.com/hiera/1/index.html

http://www.yaml.org/YAML_for_ruby.html#simple_sequence

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