September 2018
Intermediate to advanced
305 pages
7h 30m
English
Content preview from Puppet Best Practices
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Chapter 5. Resources
Resources are the heart of Puppet’s state management. Resources model a configurable entity on a node. The vast majority of resources model things you’re quite familiar with, such as:
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Files
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Packages
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Package repositories (yum, apt, chocolatey, etc.)
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Users
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cron entries
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Databases
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Windows registry keys
Resource types declare the desired state (a model) of the resource, and resource providers converge the target to match the model. Put another way, types are the interface, and providers are pluggable platform-specific implementations.
This chapter reviews the built-in Puppet types and providers, along with popular custom types. We examine how to best use virtual resources, exported resources, resource relationships, and metaparameters.
Using Resources to Implement Change
Resources evaluate and manage state of their type on nodes. No matter how complex the codebase is, the manifests are ultimately compiled down to a catalog of resource declarations, which is what the Puppet agent uses to evaluate and converge a node. Resources are the only way Puppet can idempotently affect change on your nodes.
Warning
exec resources can also affect node state, but they create untrackable, unknown changes that are antithetical to the purpose of Puppet.
Resource Types Abstract Implementation Details
A Puppet resource type is an abstraction layer and interface between Puppet and the underlying provider. You implement types in Ruby by declaring a child of the
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.