In this article, We are going to cover Jenkins Interview Questions for DevOps Engineer.
If you’re a DevOps engineer, then you will probably face the Jenkins interview questions at least once during your professional life. But have no fear, because we are here to help guide you through the top questions you need to know, that are usually asked by professionals and prepared by some of the best mentors in the field. This guide will help you nail the interview in 2020, and even further!
Jenkins Interview Questions for DevOps Engineer
- What is Jenkins for DevOps?
We are starting easy with this one. Jenkins is a free, open-source, continuous integration tool, written in Java and helps the monitoring process for integration and delivery. It also enables developers to check any errors in code and analyze the processes of coding, testing, and deployment.
- Are there any per-requisites for using Jenkins?
Yes, there are:
- Access to source code management repository like SVN or GIT.
- A build script that should work like mavens builds script.
- Which are the main advantages of Jenkins? Why do we need it?
There’s quite a lot of advantages to this tool, but the main ones you can list on your interview are:
- There is no need to check code or start to build manually, Jenkins does that for you.
- An automatic build gets started whenever there are changes in source code.
- Jenkins sends an automatic email if there are any build failures you need to know about.
- Bugs or defects are easily resolved in the early stages of development.
- It supports Continuous Integration in agile and test-driven development.
- It has Built Pipeline Support.
- Free open-source, which might be its biggest advantage.
- What’s the actual use of pipelines in Jenkins? What is their relation to Jenkins File?
This is a plugin that essentially serves to give a view of the stages or tasks that need to be performed one after the other, like a pipeline. Teams can edit, review and iterate upon the tasks. Further, the pipeline details are stored in a file that is connected to the source code repository in general, which is the Jenkins file. They can be different types, like CI CD, scripted and declarative.
- What is continuous integration in Jenkins?
When a big team works on a single project, they usually need to run integrations tests to blend all modules in one. This is a feature where isolated changes are tested frequently and reported at the same time. Also, the integration is validated through automated builds and tests.
- Which command is used to start Jenkins? How is a manual start performed?
In command Prompt, you can run D:\>Java –jar Jenkins.war, and that is used to start Jenkins with a command. On the other hand, for a manual start, you need to follow these steps:
- (Jenkins_url)/restart: Force to restart without waiting for build completion.
- (Jenkin_url)/safeRestart: Waits until the build gets completed before restarting.
- Mention some of the most useful plugins known on Jenkins.
There are many, of which we can mention:
- Maven (build tool)
- GIT (SCM)
- Selenium (continuous testing)
- Amazon EC2
- Puppet (configuration management)
- Nagios (Continuous monitoring)
- Copy artifact
- HTML publisher
- There are some steps in ensuring that your project build doesn’t break. Mention them:
- First, successfully install Jenkins on your machine and all related units.
- All code changes should be reflected successfully.
- Check the repository synchronization as well, just to make sure that all the differences and changes are saved.
- How do you set up a Jenkins job?
- First, select ‘New Job’ on the Jenkins page;
- Enter the name you want to call it and choose ‘build free-style project’, and then click Ok;
- Put details of SVN or GIT repository, where the source code has been placed.
- Give information regarding the plugins you need to use in a project, like for unit testing, code coverage, code quality.
- Mention the build tool script like Maven script, that we mentioned before.
- Collect the information regarding results.
- Configure the steps to send the notifications via emails, etc.
- Is there any relation between Hudson and Jenkins? What about Maven and Jenkins?
Hudson is the traditional name for Jenkins, which means they are the same thing.
As for Maven, it is a built tool that consists of a pom.xml file, specified in Jenkins to run the code. It defines how the software is built and its dependencies.
Here We have covered common Jenkins Interview Questions for DevOps Engineer.