What is Puppet and What Role Does it Play in DevOps?

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What is Puppet?

puppet-labs-logo

Puppet is a cross-platform client-server based application used for configuration management. It handles the software and its configurations on multiple servers. There are two versions available. One is open-source, the other is a commercial version. It works on both Linux and Windows platforms. It uses a declarative approach to automate updates, installations, and other tasks. This feature allows the software to configure those systems using files called manifests. A manifest contains the instructions for a group or type of server(s) being controlled. 

The enterprise edition contains additional functionality, such as: 

  • Provides access control based on roles that allow tasks to be delegated to an appointed group of administrators.
  • It gathers reports on system metrics of productivity and operability.
  • It also provides event inspection using journals to deliver reports about nodes, classes, and resources changes. This feature gives a simple picture of what is going on on servers managed by Puppet at this time. 

What is DevOps?

DevOps

DevOps (or Development Operations) is a set of methodologies used to increase the efficiency of development processes and software implementation by continuous integration, the interaction of various specialists, and automation tools used in IT operations. DevOps is often associated with system administration, which blends these spheres. Quite often, administrators move from an IT position into DevOps as they often share similar backgrounds. 

DevOps engineers usually have a more comprehensive range of functions, and they connect all the phases into the whole by applying process automation. They gather code, describe infrastructure, deploy testing environments promptly, and quickly update production without losing quality.     

One of DevOps’ critical tasks is to find ways of automating all processes so that businesses can update the product as quickly and regularly as possible. To accomplish this task, a DevOps specialist has a broad outlook on modern technologies. Quite often, DevOps communicates with all departments on all stages of development.

Next, we will discuss how Puppet affects DevOps and how it is useful in that environment.

Why Use Puppet?

First, let’s identify what configuration management is. Configuration management maintains and determines product characteristics by saving physical and functional attributes, design, requirements, and operational information throughout a server’s life cycle. 

puppet master

In the past, system administrators typically set up and configured software and systems manually. But when the number of servers that needed to be managed increased rapidly, tools were required to automate those processes, save time, and increase accuracy. Puppet is software that accomplishes these tasks. 

Advantages of Puppet

These are the main advantages of Puppet:

  • Puppet saves time by increasing deployment speed.
  • Unlike other tools, it keeps abreast of configuration changes at regular intervals, which increases security. (after configuration deployment in any system)
  • It uses an easy to learn language called DSL (or Domain Specific Language) to manage host configurations.
  • It grants DevOps admins the ability to create unique configurations for each host and layouts and configuration designs for multiple hosts.
  • Puppet is an inexpensive means of solving configuration bottlenecks and speed delays.
  • It easily integrates with other tools and infrastructures.   

How Does Puppet Work?

Puppet has a simple client/server architecture workflow process. The master server contains all the information about configurations for various nodes. It stores these configurations in manifest files in a central server called a Puppet master and executes those manifests on the remote client servers called agents.

puppet model
Source: cisco.com

These are the main Puppet components:

  • Master Puppet server: This server processes information connected to each agent using a configuration file and manages deployment and configurations on the agents.
  • Puppet agent: This is the server software which is managed by the master
  • Facts: These are global variables that contain details about each server, such as OS, network interfaces, etc. They are used to analyze the current status of any node.
  • Catalog: All configurations managed by Puppet are compiled into a catalog. Later, these catalogs are used to configure a target system.
  • Manifests: These are files in which resource info is stored. A manifest contains information about services, packets, files that need to be checked and edited. Manifests have .pp extension.
  • Modules: Modules are a set of files in a manifest, organized to facilitate cooperative ease of use.
  • Puppet classes: As in other programming languages, classes use repetitive code sections to organize it for increased reading and understanding.
  • Resources in Puppet block code encoding are defined by announcing resources where they can represent packets, files, users, or commands.
  • Nodes: Nodes are the managed servers that have the client installed.

What Processes Does it Use?

Now let’s review the process in steps:

  • Nodes managed by Puppet have Puppet agents installed.
  • Agents gather information about the configuration of their dedicated nodes using facts.
  • After this, agents send notifications to the master.
  • Having received the data, the master assembles a catalog based on how the nodes “should be” configured.
  • The master server then sends the catalog to agents. 
Master agent
Source: docs.oracle.com

Every agent uses these informative catalogs to make necessary changes in the nodes’ configuration. If any updates are needed, it reports that to the master server. If necessary, the Puppet master can grant access to the reports to a third-party tool.

The Puppet master and Puppet agent should interact with each other for Puppet to work without issues. A Puppet master connects to the agent through HTTPs (secure hypertext transfer protocol) to check the client; Puppet master provides an HTTP interface. When the Puppet agent makes a request or dispatch to the Puppet master, it sends an HTTPs request to one of the endpoints available in the HTTP interface provided by the Puppet master.  

Why is Puppet Used in DevOps?

Puppet is often used and applied in DevOps so let’s review the reasons for its use in DevOps. 

  • Puppet applies the model of continuous delivery to the software release cycle by automating operations and working process of deployment
  • Idle time caused by issues with configuration is minimized or can be avoided as the speed of system recovery is high thanks to Puppet and other automation systems for servers management
  • Unlike scripts, Puppet can work well in large infrastructures and automates repetitive tasks easily; also, it’s well-supported
  • Puppet has broad sectoral support in Cloud and DevOps ecosystems and is often applied in automation.
Puppet configuration

Scalability and consistency, portable infrastructure, flexibility, and constant infrastructure analysis are an essential aspect for the DevOps to pay attention to. When using Puppet, many of these problems are solved. There are many other useful tools for the DevOps to use and the range is continuously growing. The difference between the newer tools that they are not as popular, while Puppet has a solid reputation, shows significant progress, and is in use by many large IT companies.  

Conclusion

In this article, we have looked through many things connected with DevOps and Puppet. We have also reviewed key features of the tool, how it works, and why it should be used or taken into consideration as a useful tool.  

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