Puppet Interview Questions and Answers for 2024 DevOps

An organization of any size may use Puppet; however, there are certain organizations that will see greater results than others. While companies with just a few servers are unlikely to find maintaining them to be a significant challenge, larger companies may find it challenging to manage their servers manually and hence benefit more from utilizing Puppet. This is another important puppet interview question most recruiters ask. So, before you go for an interview, do research on the size of the organization.

System administrators manage their systems using Puppet software. It is a versatile application that can automate the installation and setup of the software, keep track of system changes, and much more. 

Using Puppet, you build 'manifests' that explain what each machine must perform. The particular approach ensures that there is no error while installing software. For example, if you want to deploy a new application on all of your servers, you may create a manifest that will accomplish this.

The configuration management tool Puppet works as an open-source platform. The tool has been licensed under the Apache 2.0 system, and you can download it directly from the website. Apart from this basic version, Puppet has additional functionality such as role-based access control (RBAC), orchestration, and compliance reporting. 

Also, there are a few community modules available on the Puppet Labs website. Puppet Labs is the synergy of this Puppet ecosystem consisting of the community modules and the Open Source configuration management tool Puppet.

Before Puppet existed, IT administrators used to follow a series of steps to manage and configure infrastructure consisting of more than one group of servers and systems. However, thanks to Puppet's model-driven design, it compiles all the configuration details of these systems into a catalog and sends it to every node. 

It includes all the resources, values and their relation and the required configuration modification for the failed systems. That's how Puppet helps reinstate these systems back to the running state. 

Puppet automates the processes of system and server configuration management, improves organizational infrastructure and efficiency, strengthens security, and speeds up the whole system. That's why organizations should use Puppet. Having in-depth knowledge of full course use of Puppet in an organization will help you crack the interview.

The Puppet process is straightforward. Puppet master is the name of the central server. It holds all configuration information for the several nodes it manages through manifests. Puppet agents are installed on the controlled nodes. Using facts, data about the nodes is acquired. The agents provide the facts to the puppet masters. 

The Puppet master creates a catalog to define node configurations as an outcome of collecting all the data. The catalog is then returned to the agents by the puppet master. The agents utilize these catalogs and their information to change their nodes' configuration and then report the results to the Puppet master.

In Puppet Manifests are the files that have the client configuration specified. It is written in Ruby language, and the file name ends with the .pp file extension. The default manifest for Puppet installed with apt is /etc/puppet/manifests/site.pp. This is one of the most important puppet interview questions for freshers. Working knowledge of manifests is very important to introduce yourself as a professional.  

A module is a collection of manifests and data (including facts, files, and templates) with a defined directory structure. Modules are helpful for organizing your Puppet code since they enable you to divide your code into numerous manifests. Puppet modules can be found in the module directory- /etc/puppetlabs/code/environments/production/modules.

If you're using Puppet to manage resources on a node, you'll need a catalog to detail how everything should be set up. The Puppet code manifests are compiled into a catalog by the main server. Basically, catalogs are documents that detail the ideal configuration for each node's resources that are managed by Puppet. And, the knowledge of catalogs is one of the most asked puppet interview questions.  

Puppet Agent will send a request to the Puppet Master at the specified run interval. Puppet Kick is a tool that activates Puppet Agent when Puppet Master requests it. In the earlier versions of Puppet, Puppet Kick was an important component. But, in the latest versions of Puppet, the utility of this tool has been deprecated.

When it comes to orchestration, MCollective (Marionette collective) packs a punch. You may do operations on thousands of servers all at once by utilizing premade plugins or creating your own. So, MCollective allows you to execute parallel jobs seamlessly. It uses a publish/subscribe message queue to send the commands to the parallel systems. Its ease of use made most organizations look for a system administrator with MCollective knowledge. You can consider it to be one of the most crucial puppet interview questions and answers.

To add a node to your Puppet Enterprise (PE) inventory, the main server must receive a certificate signing request (CSR) from a node that has a Puppet agent installed on it, and you must accept the CSR. Accepting the CSR enables Puppet to execute upon that node and impose your settings, adding node data to PuppetDB and making the node accessible across the PE interface. 

The agent will automatically send a certificate signing request (CSR) to the main server if you activate agents from the console. If you take a different approach, such as adding agents using an install script, you may need to launch Puppet after agent installation in order to produce the CSR. 

From the command line or PE terminal, you may accept CSRs. 

Command Line: 

• To view CSR: sudo puppetserver ca list 
• To sign a CSR: sudo puppetserver ca sign --certname <NAME> 
• To make the node available in the console: puppet agent -t 

PE Console: 

Certificates > Unsigned certificates > Accept or Reject > Accept All or Reject All. 

You can use Jira as a ticketing system for managing requests and changes; in addition to that, you can have your own internal system for handling requests. After that, you can use Git and the Puppet Code Manager app to perform standard procedures with Puppet's source code management. 

In addition, you should run Puppet updates via Jenkins's beaker testing framework as a part of your continuous integration process. 

Resources are basic units required for modeling system configurations. It describes system attributes like particular package users and networking details. 

Here is an example of resource declaration: 

user {'andrew': 
ensure => present, 
uid => '100', 
gid => '100', 
shell => '/bin/bash', 
home => '/home/andrew' 
} 

All the resources in Puppet Master are associated with a specific resource type. It offers information on the type of configuration the resource manages. Puppet has some in-built resource types; the list includes cron jobs, files, services etc. 

Also, you can save custom resources which are written in Ruby. It has exactly similar capabilities as the in-built resource type available in Puppet. 

In Puppet, a function can take one or multiple parameters as arguments. It's possible to write your own functions that will transform data and construct values. With functions, you can get a calculated value from the final expression. 

The example of function syntax in Puppet is as follows, 

function <MODULE NAME>::<NAME>(<PARAMETER LIST>) >> <RETURN TYPE> { 
... body of function ... 

final expression, which will be the returned value of the function 

} 
function apache::bool2http(Variant[String, Boolean] $arg) >> String { 
case $arg { 
false, undef, /(?i:false)/ : { 'Off' } 
true, /(?i:true)/ : { 'On' } 
default : { "$arg" } 
} 
} 

Puppet uses the Facter tool to acquire system information before requesting a catalog for a managed node or generating one using Puppet Apply; this information is called Facts. 

You can utilize these facts anywhere you choose in your manifests, as their values have been allocated to variables. 

Like facts, Puppet also uses a particular class of variables it calls built-in variables. 

When assembling a catalog, Puppet code has access to the following information: 

• Facter's essential information. 
• Both custom facts and external facts are present in your modules.

Class is a package of resources bundled together to set up a specific system in the desired way. They are specified in the manifest files of Puppet modules. 

The details of the codes used by a class may be found in its definition. While class definition does make the class usable in manifests, it does not do any evaluation. 

Below is the example class definition: 

class example_class { 
... 
code 
... 
} 

Every managed node makes a request to the Puppet master server for its own unique configuration catalog when the system is set up as an agent-master architecture. 

As part of this setup, Puppet agent software is deployed and executed on controlled nodes. Also, the Puppet Server is installed and operated on several servers.

Every Puppet agent routinely reports facts and requests a catalog from the Puppet master. The master gathers data from several sources, including the node in question, and then produces a compiled catalog of that node's contents. When a catalog is received, the Puppet agent applies the catalog to the node by verifying each resource included in the catalog. It checks for resources and makes adjustments to them if they are not in the intended condition. Also, it may report on the modifications that would have been made in "no-op" mode.

Puppet can be used independently as a stand-alone architecture. For that, each managed node has to maintain its own independent copy of the configuration data and catalog. 

In Puppet stand-alone architecture, the Puppet Apply application is executed on managed nodes as a corn job or as a scheduled activity. Apart from running automatically, it can perform manually for lesser setup chores or when setting up a new server. 

In stand-alone architecture, similar to Puppet master, Puppet Apply also requires access to several configuration data sources to create a catalog specific to the managed node. 

Then, Puppet Apply instantly applies the catalog once it is compiled by verifying each resource it represents. It checks for resources and makes adjustments to them if they are not in the intended condition. In the no-op mode, it can also inform on the necessary adjustments that might have been made. 

Once the catalog is applied, Puppet Apply saves a report on disk. It may be set up to report information centrally. This how the independent copy of the configuration data and catalog are created and maintained. 

• The etckeeper-commit-post command is included in the configuration file and must be run after pushing the configuration on the agent. 
• The etckeeper-commit-pre command is also included in the configuration file, and it is executed before the configuration has been pushed on the agent. 

An experienced professional should know about the functionality of both of these commands.

The following characters are permitted when specifying Class names and Module names: 

• Contains lowercase characters, numbers, and underscores. 
• Scope Resolution Operators, i.e. "::" are namespace separators in class name definition. 
• The acceptable characters for Variable names are listed below: 
• Can start with both capital and small letters. 
• Numerals and underscores ('_') are permitted. 
• If the variable's initial character is an underscore, it is only available inside its own local scope. 

It is a requirement for code contributors to Puppet or Facter to sign a Contributor License Agreement (CLA), without which their code will not be accepted. To locate and download Ruby-based Puppet or Facter code, the user must first connect to their GitHub account and sign a contract.

Master and apply command use codedir, but not the agent. It is the primary repository for data and code that uses an environment with manifests and modules. It includes a global module directory and Hiera data and configuration. 

This codedir is in the local directories below: 

• For Windows: C:ProgramDataPuppetLabspuppetet cetera 
• Linux : /etc/dir/PuppetLabs/code

Hiera is a system for looking up configuration data in a format called "key-value." It helps get data out of the Puppet code. For explicit parameter lookup calls for classes from a catalog, this code uses this system. This system finds data sources by looking at Puppet's facts. Its 5th version can read JSON, YAML, and EYAML data files. 

It looks for configuration data in three separate layers of configuration, starting with the global layer, then the environment layer, and ending with the module layer.

If the same resource is used more than once during the setup of Puppet, a duplicated resource declaration error will happen. By adding a virtual resource, this tool solves the problem. By declaring a virtual resource, its resources become available to collectors and the function is carried out. Also takes care of the state when the resource is used. 

Inactive virtual resources that haven't been made yet can be found in the catalog. Virtual resources are used to manage resources that meet multiple conditions across classes and sets of resources that belong to more than one class. 

Master service and with the Puppet apply command, where Puppet manifests are applied locally, load their content from modules (installed in the puppet modulepath) from one or more of the directories. It is a list of the directories Puppet looks in for modules. A separator character is used to divide these directories from the modulepath list. 

It is a colon (:) in Linux and a semi-colon in Windows (;). 

Global module directories list is the base modulepath for all environments, set up with base modulepath setting, with default value as below: 

• Regarding Linux: $codedir/modules:/opt/puppetlabs/puppet/modules 
• If you're using Windows: $codedirmodules 

During normal operation, Puppet stores data it has made in a cache directory called vardir. This information can be used to analyze things. If you use the agent or apply command, you can find the Cache directory at one of the following places: 

• For Windows, the address is C:programmedPuppetLabspuppetcache. 
• On Linux, the location is /opt/puppetlabs/puppet/cache. You can also use the –vardir option at the command line to set the location of the puppet cache directory. We can change where vardir files and directories are stored by making changes to Puppet.conf. 

As part of pre-installation preparations while installing Puppet, users need to follow the steps below, 

• First, decide on the deployment type. Puppet has both client-server architecture and stand-alone architecture when it comes to deployment. Before you start installing, you need to decide on a deployment type. 
• The agent master architecture is the default, and if you are willing to use it, decide which server will be the Puppet master. The Puppet master is another dedicated system, and it should be reachable on a reliable hostname. A Windows machine can't work as a Puppet Master. 
• Find out the OS versions and system requirements. Check the system requirement for the particular version from the official website. 
• Check the network configuration. As part of the configuration, the Puppet master server has to accept inbound connections on port 8140. Apart from that, Agent nodes must be able to connect to the Puppet master server on that port. 
• Start a server-side timekeeping system on the Puppet master. On the Puppet master server that works as a certificate authority, the time must be configured correctly. 

Remediate reduces the risk of cyberattacks and security breaches by offering insight into infrastructure-wide risks and prioritization and correction options. With Remediate, you can avoid the cumbersome and error-prone manual data transfer procedures across teams.

Relay is an event-driven automation platform from Puppet. It is a service that allows you to integrate tools, APIs, and infrastructure and automates routine operations via easier, smarter workflows. The application links infrastructure events to process execution so that, e.g., when a new JIRA ticket or GitHub problem is raised, your workflow may initiate deployments or send alerts. 

Bolt is an open-source orchestration software that automates the manual input required for infrastructure maintenance. Utilize Bolt to automate actions that you execute on the basis of as-needed or as part of a larger orchestration process. 

Bolt may be used to patch and update systems, diagnose servers, deploy applications, and stop and restart services, among other tasks. Bolt may be installed on a local machine and creates a connection to remote targets through SSH or WinRM; thus agent software is not needed. 

There is a stable collection of test nodes in a permanent test environment where all modifications must succeed prior to being integrated into the production code. The test nodes are a smaller version of the production infrastructure as a whole. They are either temporary cloud instances or private cloud virtual machines (VMs) with extended lifetimes. These nodes spend their whole lifetime in the test environment.

The Puppet Module list command will show all installed modules along with their installation path. 

# verify the module is installed 
$ sudo /opt/puppetlabs/bin/puppet module list 
/etc/puppetlabs/code/environments/production/site 
|-- garethr-docker (v5.3.0)

PSON is a form of JSON that Puppet utilizes to serialize data for network transmission or storage on a disc. JSON needs the serialized form to be a valid unicode (usually UTF-8). A PSON string is a string of ASCII-encoded 8-bit data. It must begin and conclude with "(0x22 ASCII) characters.

In my last organization, the development team requested root access to Puppet-managed test machines. They were required to perform certain configuration changes. 

We resolved it by meeting with them on a weekly basis so that we could agree on a method for developers to submit configuration changes and help them make many of the required changes. 

We managed to come up with a strategy for developers to update individual configuration values directly using data abstracted from Hiera via our mutual cooperation. In fact, in partnership with us, we taught one of the developers how to build Puppet code. 

In my previous projects, I often visited the Puppet Labs website to learn how to utilize the program's built-in capabilities more effectively. One of our customers had difficulty managing, organizing, and supporting tickets. Utilizing the open-source community tools inside Puppet Lab, I was able to provide them with system integration of Puppet modifications that outlined their business operations.  

You can upgrade Puppet and Facter using the operating system package management system. This can be achieved using either the vendor's repository or Puppet Labs' public repositories. 

Note: Facter is Puppet's library for analyzing systems on several platforms. It finds and returns node-specific data, which may then be used in the Puppet manifests as variables. The Facter gem is available for download at https://rubygems.org/. You can configure Facter if you have Ruby already by typing: 

gem install facter

Use the puppet module install command with the module's complete name. 

The format of the full name of a Forge module is <username>-<modulename>.  

Example to install puppetlabs-apache: puppet module install puppetlabs-apache 

The tool uses several types of plug-ins. The list includes: 

• Custom resource types and providers (written in Ruby). 
• Custom facts (written in Ruby). 
• External facts (executable scripts or static data). 
• Custom functions are written in the Puppet language. 
• Custom functions are written in Ruby. 
• Miscellaneous utility Ruby code used by other plug-ins. 
• Custom Augeas lenses.

There are Ruby versions that have been specially tested with Puppet, whereas other versions have not. You might use the "ruby -version" command to determine the version of Ruby installed on the system. Puppet versions greater than Puppet 4 are independent of the Ruby version of the operating system since they have their own Ruby environment. 

Now, you may install a puppet agent through any version of Ruby or without installing Ruby on any machine. Puppet Enterprise is independent of the Ruby version of the operating system due to the inclusion of its own Ruby environment. It is possible to install PE with a different version of Ruby or on systems without Ruby.

Unlike other CI/CD tools, Continuous Delivery for Puppet Enterprise is designed specifically for the needs of infrastructure as code. DevOps operations in infrastructure-as-code settings are made possible by this Puppet Enterprise add-on. Teams may add a new dimension of visibility and adaptability to their Puppet setup by including source control repositories. The knowledge of this tool is tested in interviews. That's why we have added it to our list of puppet interview questions (experienced).  

Puppet Remediate removes tedious and error-prone processes in the vulnerability management workflow, such as the manual data handover process between InfoSec and IT Ops and the classification and remediation of vulnerabilities. 

• Reduce vulnerability remediation time from weeks or days to less than a day. 
• Reduce the number of overall system vulnerabilities 
• Reduce or eliminate the time spent creating status reports 
• Complete audits quicker and with less effort 

I utilize Puppet's virtual resources to describe resource states. Because virtual resources do not need to define the precise state, I do not enter categories into the computer until all coding is complete. This saves me time even while letting me review my programmes for further problems.