Top Puppet Interview Questions You Must Prepare In 2023

Puppet Interview Questions & Answers

Puppet is the most mature and most widely used tool for Configuration Management.

1. What is a Puppet?

Puppet is a configuration management tool that helps automate the configuration and maintenance of software systems. It is often used in the context of DevOps, which is a set of practices that aims to improve the collaboration and communication between development and operations teams in order to deliver software more quickly and reliably.

In the context of DevOps, Puppet is used to automate the deployment and management of applications and infrastructure. It allows developers to define the desired state of their systems using declarative configuration files written in the Puppet Domain Specific Language (DSL). These configuration files, called “Puppet manifests,” specify the software and configuration settings that should be installed and configured on each node in the system. Puppet then uses these manifests to ensure that all nodes in the system are in the desired state.

Puppet can be used to automate a wide range of tasks, including the installation and configuration of operating systems, applications, and infrastructure components such as servers, networking equipment, and storage. It is designed to be scalable, flexible, and easy to use, and it integrates with a variety of tools and platforms to enable automation across the entire software delivery lifecycle.

2. What are the Features of Puppet?

Puppet is an open-source configuration management tool that helps organizations automate the process of delivering and operating software. It is often used in DevOps (development and operations) environments to manage infrastructure as code and enable continuous delivery. Some key features of Puppet include:

1. Declarative configuration management: Puppet uses declarative language to describe the desired state of an infrastructure, which allows users to define what they want rather than how to achieve it.
2. Model-based infrastructure: Puppet allows users to model their infrastructure as code, which enables version control, testing, and collaboration.
3. Extensible and modular design: Puppet is designed to be modular and extensible, with a rich ecosystem of community-developed modules and tools that can be used to manage a wide range of infrastructure components.
4. Agent/server architecture: Puppet uses an agent/server architecture, where agents run on managed nodes and communicate with a central server to retrieve configuration instructions and report on the current state of the infrastructure.
5. Cross-platform support: Puppet supports a wide range of operating systems and cloud platforms, including Windows, Linux, and Unix-based systems, as well as cloud platforms like AWS and Azure.
6. Scalability and performance: Puppet is designed to scale to manage large, complex infrastructures, with features like parallel execution and distributed architecture to improve performance and reduce the time required for deployments.

Now, you should describe how Puppet Master and Agent communicate.

Puppet has a Master-Slave architecture in which the Slave has to first send a Certificate signing request to the Master and the Master has to sign that Certificate in order to establish a secure connection between Puppet Master and Puppet Slave as shown in the diagram below. Puppet Slave sends a request to Puppet Master and Puppet Master then pushes configuration on Slave.

Refer to the diagram below that explains the above description:

3. How does Puppet work?

In a DevOps environment using Puppet, infrastructure is typically managed using code written in the Puppet declarative language. This code, also known as “Puppet manifests,” is stored in version control and used to define the desired state of infrastructure.

The Puppet server, also known as the “Puppet master,” is responsible for managing the configuration of the infrastructure. It stores the Puppet manifests and serves them to managed nodes, which are the servers and other infrastructure components that are being managed by Puppet.

Each managed node has a Puppet agent installed on it, which is a small piece of software that communicates with the Puppet master and applies the configuration specified in the Puppet manifests. The Puppet agent runs periodically, checking in with the Puppet master to see if any changes have been made to the configuration. If changes have been made, the Puppet agent retrieves the updated configuration and applies it to the node.

The process of applying the configuration is known as “converging,” and it involves making any necessary changes to the node to ensure that it matches the desired state specified in the Puppet manifests. This can include installing and configuring software, creating and modifying files, and managing system resources like users, groups, and permissions.

Using Puppet in a DevOps environment allows teams to automate the process of delivering and operating software, ensuring that their infrastructure is consistently configured and compliant with corporate standards. It also enables teams to track changes to their infrastructure over time and roll back any unintended changes.

For this question just explain Puppet Architecture. Refer to the diagram below:

The following functions are performed in the above image:

• The Puppet Agent sends the Facts to the Puppet Master. Facts are basically key/value data pair that represents some aspect of the Slave state, such as its IP address, up-time, operating system, or whether it’s a virtual machine.
• Puppet Master uses the facts to compile a Catalog that defines how the Slave should be configured. The catalog is a document that describes the desired state for each resource that Puppet Master manages on a Slave. I will explain catalogs and resources in detail later.
• Puppet Slave reports back to Master indicating that Configuration is complete, which is visible in the Puppet dashboard.

4. What is Puppet Module and How it is different from Puppet Manifest?

In Puppet, a module is a collection of related code and data that can be used to manage a specific aspect of your infrastructure. Modules typically include one or more manifests, which are files written in the Puppet language that describes the desired state of your infrastructure.

In a DevOps workflow, Puppet modules can be used as part of the infrastructure as code (IaC) process. This means that the configuration of the infrastructure is managed using code, rather than manual processes. The code is stored in version control and is used to create and update the infrastructure as needed.

One key difference between modules and manifests is that modules are a way to organize and reuse code, while manifests are the actual files that contain the code. Modules can contain multiple manifests, and a single manifest can be used to manage resources across multiple nodes. Modules can also include additional files and data, such as templates and custom types and providers, which can be used to extend the functionality of Puppet.

In a DevOps workflow, Puppet modules can be used to automate the configuration and management of specific components of the infrastructure, such as a web server or a database. By using modules, organizations can ensure that the configuration of their infrastructure is consistent and correct, even as it changes over time. Modules also enable collaboration between development and operations teams, as the infrastructure as code can be stored in version control and reviewed and tested by both teams before being applied to the nodes.

5. What is Facter in Puppet?

 Facter is a tool that is included with Puppet and is used to gather information about a system. Facter collects facts about a system, such as the operating system, the hostname, the IP address, and the installed packages. These facts can then be used in Puppet manifests to make decisions about how to configure a node.

In a DevOps workflow, Facter can be used in conjunction with Puppet to automate the configuration and management of infrastructure. For example, you might use Facter to gather information about a node and then use that information to customize the configuration of a service using Puppet.

For example, you might use Facter to determine the operating system of a node and then use that information to include the appropriate package resources in your Puppet manifest. You might also use Facter to determine the hostname of a node and use that information to customize the configuration of a service.

Facter is useful in a DevOps workflow because it allows you to write manifest code that is flexible and can adapt to different environments and systems. This makes it easier to automate the configuration and management of your infrastructure, ensuring that it is consistent and correct, even as it changes over time.

6. What is Puppet Catalog?

In Puppet, a catalog is a compiled version of a manifest that contains a detailed description of the desired state of a node’s resources. The catalog is used by the Puppet agent to determine the actions that need to be taken to ensure that the actual state of the node matches the desired state.

In a DevOps workflow, Puppet can be used as part of the infrastructure as code (IaC) process. This means that the configuration of the infrastructure is managed using code, rather than manual processes. The code is stored in version control and is used to create and update the infrastructure as needed.

In this context, the Puppet catalog can be thought of as the compiled version of the infrastructure as code. It contains a detailed description of the desired state of the infrastructure, including the resources that should be managed on each node and the desired state of those resources. The catalog is used by the Puppet agent to apply the configuration to the nodes and ensure that the infrastructure is in the desired state.

Using a Puppet catalog in a DevOps workflow allows organizations to automate the configuration and management of their infrastructure, ensuring that it is consistent and correct, even as it changes over time. It also enables collaboration between development and operations teams, as the infrastructure as code can be stored in version control and reviewed and tested by both teams before being applied to the nodes.

7. What size organizations should use Puppet?

DevOps is a software development and delivery method that emphasizes collaboration between development and operations teams, as well as automation of processes. It is designed to help organizations deliver software faster and more reliably.

Puppet is a configuration management tool that can be used as part of a DevOps workflow to automate the configuration and management of infrastructure. It is typically used by organizations that have a large number of servers or devices that need to be managed and configured consistently.

As with any tool, the size of the organization that should use Puppet as part of a DevOps workflow will depend on the specific needs and requirements of the organization. In general, however, Puppet is well-suited for use in medium to large organizations that need to manage a large number of servers or devices, and that have a need for automation and collaboration between development and operations teams.

8. How should I upgrade Puppet and Facter?

There are several steps you can follow to upgrade Puppet and Facter in a DevOps environment:

1. Determine the current version of Puppet and Facter: You can check the current version of Puppet and Facter by running the following commands:

puppet --version
facter --version

2. Check the compatibility of your infrastructure: Before upgrading, it is important to ensure that your infrastructure is compatible with the new version of Puppet and Facter. You can check the compatibility matrix for the desired version of Puppet to see which versions of Facter and other dependencies are supported.
3. Backup your current installation: It is always a good idea to make a backup of your current installation before upgrading, in case you need to roll back the changes. You can make a backup of your Puppet configuration and data by copying the ‘/etc/puppetlabs‘ directory.
4. Install the new version of Puppet and Facter: There are several ways to install the new version of Puppet and Facter, depending on your operating system and installation method. Some options include using the package manager of your operating system, downloading the installation packages from the Puppet website, or using the Puppet Enterprise installer.
5. Test the new installation: After upgrading, it is important to test the new installation to ensure that everything is working as expected. You can do this by running a few simple Puppet commands, such as ‘puppet agent -t‘ or ‘puppet resource'.
6. Roll back the changes if necessary: If you encounter any issues after upgrading, you can roll back the changes by restoring the backup of your previous installation and restarting the Puppet services.

9. What is the Command to check requests of Certificates from Puppet Agent (Slave) to Puppet Master?

To check the requests for certificates from a Puppet agent (also known as a “slave”) to a Puppet master, you can use the ‘puppet cert list' command on the Puppet master. This command will list all of the certificate requests that are pending on the master, including the hostname and fingerprint of each requesting agent.

For example, you can run the following command on the Puppet master to list the pending certificate requests:

puppet cert list --all

This will list all of the certificate requests that are pending on the master, including those that have been signed and those that are still waiting to be signed.

If you want to see only the requests that are still pending and have not yet been signed, you can use the ‘--signed' flag to filter out the signed requests:

puppet cert list --all --signed

You can also use the '--verify‘ flag to verify the status of a specific certificate request, by specifying the hostname of the agent that made the request:

puppet cert list --verify <hostname>

This will show the status of the specified request and indicate whether it has been signed or is still pending.

10. What is the use of etckeeper-commit-post and etckeeper-commit-pre on Puppet Agent?

‘etckeeper-commit-post' and ‘etckeeper-commit-pre' are scripts that can be used in conjunction with the etckeeper tool, which is a collection of scripts that can be used to track changes to the /etc directory on a Unix-like operating system.

'etckeeper-commit-pre' is a script that is run before an ‘etckeeper' commit. It can be used to perform any tasks that need to be completed before the commit, such as generating files that need to be included in the commit or modifying the contents of the '/etc ‘directory in some way.

‘etckeeper-commit-post’ is a script that is run after an ‘etckeeper‘ commit. It can be used to perform any tasks that need to be completed after the commit, such as sending notifications or cleaning up temporary files.

On a DevOps Puppet Agent, these scripts might be used to perform tasks related to the configuration management of the system, such as committing changes to the '/etc” directory to version control after they have been made by the Puppet agent.

11. What characters are permitted in a class name? In a module name? In other identifiers?

In DevOps, class, and module names in the Puppet configuration management tool must adhere to certain naming conventions. In general, class and module names should be composed of alphanumeric characters and underscores, and must start with a lowercase letter or an underscore. Here are some examples of valid class and module names:

• myclass
• my_module
• _private_class

Other identifiers, such as variable names and function names, can also include alphanumeric characters and underscores, but must start with a lowercase letter or an underscore. Here are some examples of valid identifiers:

• $my_variable
• $myVariable
• function_name

It’s worth noting that, while these naming conventions are generally followed in Puppet, it’s possible to use other characters in class and module names by enclosing the name in quotes. For example, the following class name is also valid:

• "my-class"

However, it’s generally considered a good practice to stick to the naming conventions described above, as it can make your Puppet code easier to read and maintain.

12. Does Puppet runs on Windows?

Yes, Puppet can be run on Windows operating systems. Puppet is a cross-platform configuration management tool that can be used to automate the configuration and management of systems running various operating systems, including Windows.

To use Puppet on a Windows system, you will need to install the Puppet Agent software on the system. The Puppet Agent is a lightweight software agent that runs on the managed systems and communicates with the Puppet Master, a central server that stores the configuration information for the managed systems.

Once the Puppet Agent is installed on a Windows system, you can use Puppet to manage the configuration of the system and ensure that it stays in compliance with your desired configuration. This can include installing and configuring software, managing system services, and more.

Puppet is commonly used in DevOps environments to automate the deployment and management of systems and applications. It can be especially useful in environments where there are a large number of systems to manage, as it can help to ensure that all systems are consistently configured and maintained.

13. Which Version of Ruby does Puppet Support?

Puppet supports multiple versions of Ruby, and the specific version that is supported can vary depending on the version of Puppet that you are using.

Puppet 6, the current major version of Puppet, supports the following versions of Ruby:

• Ruby 2.5
• Ruby 2.6
• Ruby 2.7

Puppet 5, the previous major version of Puppet, supported the following versions of Ruby:

• Ruby 2.1
• Ruby 2.2
• Ruby 2.3
• Ruby 2.4

It’s worth noting that the specific version of Ruby that is supported can also depend on the operating system you are using. For example, some older versions of Puppet may not support the latest versions of Ruby on certain operating systems.

In general, it’s a good idea to use the latest supported version of Ruby with Puppet to ensure that you have access to the latest features and bug fixes. However, if you have specific requirements or dependencies that require you to use an older version of Ruby, you may need to use an older version of Puppet that supports that version of Ruby.

14. Which open-source or community tools do you use to make Puppet more powerful?

There are many open-source and community tools that can be used to extend the capabilities of Puppet and make it more powerful in a DevOps environment. Some of the tools that are commonly used with Puppet include:

• Hiera: Hiera is a tool for separating data from code in Puppet. It allows you to store configuration data in a hierarchical, key-value format, which can be accessed by Puppet code using lookup functions.
• R10K: R10K is a tool for managing Puppet environments and modules. It allows you to manage multiple Puppet environments from a single Git repository, making it easier to deploy and manage Puppet code across multiple systems.
• PuppetDB: PuppetDB is a tool for storing and querying data about managed systems and the resources they contain. It can be used to store data collected by Puppet, such as the state of resources on managed systems, and can be queried using the PuppetDB Query Language (PQL).
• Puppet Debugger: Puppet Debugger is a tool for debugging Puppet code. It allows you to step through your code and inspect variables, functions, and other aspects of the code as it is being executed.
• Puppet Visualize: Puppet Visualize is a tool for visualizing the relationships between resources in a Puppet environment. It can be used to understand how resources depend on each other and can help to identify potential issues or bottlenecks in the configuration.

These are just a few examples of the many tools that are available to extend the capabilities of Puppet and make it more powerful in a DevOps environment. There are many other open-source and community tools that can be used with Puppet, depending on your specific needs and requirements.

15. Tell me about a time when you used collaboration and Puppet to help resolve a conflict within a team?

Explain to them about your past experience with Puppet and how it was useful to resolve conflicts, you can refer to the below mention example:

The development team wanted root access on test machines managed by Puppet in order to make specific configuration changes. We responded by meeting with them weekly to agree on a process for developers to communicate configuration changes and to empower them to make many of the changes they needed. Through our joint efforts, we came up with a way for the developers to change specific configuration values themselves via data abstracted through Hiera. In fact, we even taught one of the developers how to write Puppet code in collaboration with us.

In a DevOps environment, collaboration is an important part of the process of developing, deploying, and maintaining software and systems. Teams often use a variety of tools and practices to facilitate collaboration, including version control systems, project management tools, and communication platforms.

One way that collaboration and tools like Puppet can be used to resolve conflicts within a team is by providing a clear and consistent process for managing changes to systems and applications. By using a configuration management tool like Puppet to automate the deployment and management of systems, teams can ensure that changes are made in a consistent and repeatable manner, which can help to reduce the risk of conflicts arising from conflicting changes.

Additionally, by using tools like version control systems and project management tools, teams can track the changes that are being made to systems and applications, and can collaborate more effectively to resolve any conflicts that may arise. These tools can also help teams to identify potential conflicts early on, which can allow them to be addressed before they cause any issues.

Overall, collaboration and tools like Puppet can be a powerful combination for helping to resolve conflicts within a team, by providing a clear and consistent process for managing changes and facilitating communication and collaboration among team members.

Puppet Interview Questions for Experienced

16. Can I access environment Variables with Facter in Puppet?

Yes, it is possible to access environment variables with Facter in DevOps Puppet. Facter is a tool that is included with Puppet and is used to gather information about managed systems. This information, known as “facts,” can be used by Puppet to configure systems and ensure that they are in compliance with the desired configuration.

Facter can be used to gather a wide variety of information about a system, including information about the operating system, hardware, and installed software. One type of information that Facter can gather is environment variables, which are variables that are set at the operating system level and can be accessed by processes running on the system.

To access environment variables with Facter, you can use the ‘facter‘ command-line tool, which is included with Puppet. For example, to display all of the environment variables on a system, you can use the following command:

facter -p

This will display a list of all of the environment variables and their values on the system. You can also use the ‘facter' command to display the value of a specific environment variable by specifying the variable name as an argument. For example, to display the value of the HOME environment variable, you can use the following command:

facter -p HOME

You can also use ‘Facter’ facts in your Puppet code to access environment variables. For example, to access the value of the ‘HOME' environment variable in a Puppet manifest, you can use the following code:

$home = $::home

This will assign the value of the ‘HOME' environment variable to the ‘$home' variable, which you can then use in your Puppet code as needed.

Overall, Facter is a powerful tool for gathering information about systems, and can be used to access environment variables and other types of information in a DevOps Puppet environment.

17. What is the use of Virtual Resources in Puppet?

In DevOps Puppet, virtual resources are a way to specify the desired state of a resource without actually creating the resource. Virtual resources are similar to real resources in that they have a type, a title, and a set of attributes that define their desired state. However, unlike real resources, virtual resources are not actually created on the managed systems.

Virtual resources are often used to specify dependencies between resources, or to ensure that a particular resource is present on a system without actually creating it. For example, you might use a virtual resource to ensure that a particular package is installed on a system, without actually installing the package.

To create a virtual resource in Puppet, you can use the @ symbol before the resource type and title. For example, to create a virtual package resource, you might use the following code:

@package { 'mysql-server':
  ensure => installed,
}

This will create a virtual package resource with the name 'mysql-server‘ and the attribute ensure set to ‘installed'. This virtual resource can then be used to specify dependencies for other resources, or to ensure that the 'mysql-server‘ package is present on the system without actually installing it.

Virtual resources can be useful in a variety of situations, such as when you want to specify dependencies between resources without actually creating the resources, or when you want to test the effects of a resource without actually creating it. They can also be used to manage resources that cannot be managed directly, such as resources that are created by other tools or processes.

18. What are Puppet Manifests?

In DevOps Puppet, a manifest is a file that contains instructions for configuring systems and ensuring that they are in compliance with the desired configuration. Manifests are written in the Puppet Domain Specific Language (DSL), which is a declarative language that is designed specifically for use with Puppet.

Manifests are used to specify the resources that should be present on a system, and the desired state of those resources. Resources can be anything that can be managed by Puppet, such as files, packages, users, and services. Manifests can also contain other Puppet code, such as conditionals and loops, which can be used to control the flow of execution and make the manifest more flexible and adaptable.

Manifests are typically organized into classes, which are groups of related resources that can be managed together. For example, you might create a class for managing the Apache web server and another class for managing a database server. These classes can then be included in other manifests or used as building blocks for more complex configurations.

Manifests are an important part of the Puppet configuration management process, as they are used to specify the desired state of systems and ensure that they remain in compliance with the desired configuration over time. They can be used to automate a wide variety of tasks, such as installing and configuring software, managing system services, and more.