Top 16 Useful Jenkins Interview Questions and Answers for DevOps Engineers

So, DevOps Engineers – your skills in Jenkins are solid, are they? Excellent. Time to study up on Jenkins interview questions so you can land a great job using those skills to pay the bills. According to Indeed, almost 17,000 available positions today require Jenkins abilities – so, if you apply to one or more of them, you’re sure to face some questions about it. If you land a job, you’ll make an average of $113,354 – no chump change. Why not prepare answers in advance? We’ve made it simple by providing common Jenkins interview questions and answers for you. No need to thank us – unless you want to cut us a bonus check upon your hire, that is. Here goes.

What is Jenkins?

If you get this wrong, you’ll not get the job. Heck, you might want to reevaluate your skillset altogether. So, answer as follows: Jenkins automates source code repositories and plugins written in Java and relies on continuous integration and delivery. It continually provides work on a project by using its software with various testing tools and methodologies. Got it?

Why is Jenkins used?

This explains the crucial reasons why your job exists. You better know this! Basically, Jenkins is used for testing and reporting about isolated changes in a larger code base in real-time.

What is the difference between Maven and Jenkins?

Ahh, the compare/contrast dichotomy. Gotta love this one. Easy, peasy. A maven is a build tool, a successor of Ant. It helps to build and version control. However, Jenkins is continuous and integrated, so you can use it to self-regulate an implementation process. On the other hand, you use Maven for a build. No problem!

What is the difference between Hudson and Jenkins?

This is kind of a trick question, as you should know that there is no difference between Jenkins and Hudson. Jenkins is the new Hudson. It is more of a rename because everyone moved to it from Hudson.

Define the process of Jenkins.

This is a lengthy answer, and more technical, so take your time memorizing this Jenkins interview question. Here goes: 

  1. Because Jenkins checks changes in repositories regularly, developers must secure their code regularly, too. SCM can be GIT, SVN, and TFS. GIT and SVN are widely used now.
  2. Once the changes are defined, Jenkins detects them and use them to prep a new build.
  3. Next, Jenkins will transverse through various stages in its usual pipeline. As one stage successfully finishes, the process moves on to another.
  4. If a stage fails, the Jenkins build will stop there and the software will email to the team using it. When completed successfully, the code implements itself in the proper server so that testing begins.
  5. If the testing stage successfully passes, Jenkins shares the results with the team using it. The whole process keeps iterating whenever code is committed in SCM.

What prerequisites does Jenkins need?

Just like you needed to take English 101 before you could take upper-division courses in college, you must have a few things before you can use Jenkins. They are:

  • Access to a source code management repository like GIT or SVN.
  • A build script that should be working, such as Maven.

What does continuous integration mean?

This answer basically interrogates your knowledge of how Jenkins works. Explaining it well will really help prove you know your information! So, explain that continuous integration is where isolated changes are tested frequently and reported at the same time. Afterward, changes get added to a larger codebase. This practice happens rapidly, often several times a day. Also, automated tests and builds validate this process. 

Why is Jenkins used with Selenium?

Selenium allows you to test Jenkins whenever software changes or sends it into a new environment. Jenkins will then schedule tests to run at the times you specify using Selenium. 

Name some of the top Continuous Integration tools.

Impress your interviewer by knowing not 1, not 5, but 8 of them. The top Continuous Integration tools are:

  • Jenkins
  • TeamCity
  • Travis CI
  • Go CD
  • Bamboo
  • GitLab CI
  • CircleCI
  • Codeship

What is a CI/CD pipeline?

CI/CD pipeline is a continuous integration and deployment pipeline it is important because it reduces manual, error-prone work, providing higher quality software.

What is a build pipeline?

These Jenkins interview questions are getting harder, no? Don’t worry – we know you can learn them. For this, the answer is: Build pipeline is the process of automatically starting another job (s) after the execution of a job. Thus, you can start building multi-step build pipelines or rebuild a project when a part of it is updated. 

What is a Jenkins Pipeline?

You can really bedazzle your interviewer with your answer here. Pay attention! The answer is, the Jenkins Pipeline plugin is based on a Domain Specific Language (DSL) in Groovy. This Pipeline plugin makes them scriptable and can help you powerfully make complex DevOps pipelines. Groovy, right?

What is a DSL, Jenkins?

If you’re asked this, you’re really impressing your interviewer, getting closer to moving on in the interview process. Don’t lose focus now! The DSL Jenkins “Job DSL / Plugin” comprises two items: The Domain Specific Language (DSL) that describes functions using Groovy, and a Jenkins plugin that controls the codes and updates that result within the Jenkins job being done. 

Provide three ways for Jenkins to authenticates users.

Jenkins authenticates users via:

  1. An internal database with user data and credentials. (The default.)
  2. By using the Lightweight Directory Access Protocol server.
  3. By using the authentication mechanism used by the application server the Jenkins code is deployed on.

What is the standard process to configure third-party tools in Jenkins?

Tell your interviewer you use a  four-step standard process for third-party tools, such as Artifactory, Node, SonarQube or Git as follows and you’ll ace this question:

  • Install the third-party software.
  • Install a Jenkins plug-in supporting the third-party tool through the Jenkins administration console.
  • Configure the tool in the “Tools” area of the Manage Jenkins section of the admin console.
  • When all this is done, the plug-in is ready to go.

This is one of the trickier Jenkins interview questions, but, thanks to us, you can handle it!

Detail one Jenkins environment variable used in a shell script or batch file.

This one is advanced and shows your knowledge, so let it rip. Convince your interviewer you know your stuff here. The answer like this: 

Many default Jenkins environmental variables are out there. Some are:

  1. $JOB_NAME
  2. $NODE_NAME
  3. $WORKSPACE
  4. $BUILD_URL
  5. $JOB_URL

Then add, when you make new Jenkins plugins, new environmental variables arise. 

Had enough? Surely, knowing the answers to these 16 Jenkins interview questions will solidify your ability to land one of those nearly 17,000 jobs available right now requiring its use. Of course, you’ll have to use your own sparkle and charm to cement the deal – we can’t help you with those. 

However, we can help you advance your understanding of Jenkins and DevOps in general. In fact, we offer this amazing DevOps Certification Training Course that will put you on the fast track to landing a highly desirable position making a great salary. DevOps bridges the gap between software developers and operations and, as you saw above, is a highly desirable field right now. In this course, you’ll learn not only Jenkins but also Git, Docker,

Cucumber, Ansible, TeamCity, and Nagios. And, you will comprehend the hard concepts of continuous development, automation of configuration management and more. Through 56 hours of in-depth blended learning and 24 live demos of the most popular DevOps tools, you’ll complete 10+ real Industry projects with integrated labs, culminating in earning a certificate proving you’re DevOps royalty. 

With the said certificate in hand and answers to Jenkins interview questions in the brain, you’ll be unstoppable. What are you waiting for?
 

About the Author

Shivam AroraShivam Arora

Shivam Arora is a Senior Product Manager at Simplilearn. Passionate about driving product growth, Shivam has managed key AI and IOT based products across different business functions. He has 6+ years of product experience with a Masters in Marketing and Business Analytics.

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