Be it monitoring the repeated task during a development project or identifying the errors or bugs in the initial stages of product development, Jenkins has emerged as a popular tool for every software development company. Thus, it is not a surprise that when you appear for a DevOps interview, the interviewer can ask you questions related to Jenkins. Therefore, to help you crack the upcoming interview round, we have listed the most frequently asked Jenkins interview questions along with answers.
This basic to advanced Jenkins interview guide will be useful for both fresher and experienced professionals. Also, these questions are prepared with the help of DevOps experts who have experience of taking frequent interview rounds.
List of Top Jenkins Interview Questions
Q1. What do you know about Jenkins?
Ans. Jenkins, which is written in Java, is a free open source continuous integration tool and automation server. It is designed to monitor continuous integration and its delivery. Jenkins automates the software development process and is integrated into each step of the software development lifecycle.
With the help of different plugins used for several software development stages, Jenkins accomplishes continuous integration.
Q2. What is Continuous Integration?
Ans. It is a practice used in the development in which as soon as the developers commit the changes in source code, software testing is initiated. Once the testing phase is clear, the build goes for deployment. Once the deployment stage is successful, code is sent for production. Thus this is a continuous cycle in which commit, build, test, and deploy stages are recurring. Hence, it is called continuous integration or continuous deployment. The pipeline of continuous integration consists of tools that help in the host, monitor, compile, and test code.
Below is the Process of Continuous Integration:
Q3. What is Distributed Builds Architecture in Jenkins?
Ans. Jenkins master has its own executors and resources, which can be operated on their own and can execute and manage the build environment. However, with this ‘standalone’ configuration, one can run out of resources as soon as the total number of projects increases. Thus, it is not a good option to run build on central machines. Hence, in such situations, the concept of distributed build architecture comes into the picture. Through this, the users need to configure the Jenkins machines to be the slave machines so that they can easily handle the load of the master Jenkins server.
Here, the slave is a computer on which the unload build projects set up is done to distribute the build task. In this method, either one can stick to a specific machine for a particular build, or they might choose to roam between multiple slaves. It is also termed as master and slave machines.
Steps in which the Distributed Architecture of Jenkins Works:
Q4. What is AWS Secrets Manager?
Ans. It is a precise solution for securing secret storage. In AWS Secrets Manager, one can define any secret for the AWS account just for once, and later, they can give permissions to the users for using this secret. It integrates with other AWS services like:
- Secret entry management
- Secret value management
- Access control
- Secret encryption
Q5. How is Jenkins different from Bamboo?
Ans. Both Jenkins and Bamboo are continuous integration tools used for agile development. Also, both have the same starting point, i.e. create a plan outlined with a series of tasks. However, they have minor yet crucial differences and depending upon the business, budget, user-interface, plug-ins, and configuration, one can choose between them.
|Open-source||Not open source|
|Free||Different charges for build agents|
|Supports Windows, Ubuntu, Red Hat, Mac Operating systems||Supports Windows, Linux, Solaris Operating systems|
|Works on browsers like Chrome, Firefox, Internet Explorer||Works on browsers Firefox, Chrome, Safari, Edge|
|Multiple plug-ins are available||Fewer plug-ins|
|Various communities support it as it is open source||Less support|
Q6. Is there any prerequisite for Jenkins?
Ans. To use Jenkins, one requires two things:
- Source code repository like Git repository
- Build script like Maven script
Q7. Do you think Jenkins is better than Jira?
Ans. Jira is a software used by agile teams for project planning, tracking, and managing. Through Jira, one can customize their workflows, collaborate teams, and release software. It is also known as the incident management tool. Professionals working in the software project development team, help desk system, etc. use Jira for bug tracking. Below is the concept of Jira.
However, when compared with Jenkins, Jira’s UI is difficult to navigate. Whereas, Jenkins’ easy to deploy configuration and its automatic rollback features attract various users. It is also the best option for conducting continues builds.
Q8. List down some essential plugins of Jenkins.
Ans. Below is the list of popular Jenkins plugins:
|Jenkins Plugins||Monitoring||Performance Enhancers||Scaling Jenkins Setup||Source Control Management (SCM)||Other Essential Plugins|
|Dashboard View Plugin||Monitoring Plugin||Performance Plugin||Kubernetes Plugin||SCM API||Maven 2 project|
|View Job Filters Plugin||Metrics Plugin||Performance Publisher Plugin||Amazon ECS Container Service||Git Plugin||HTML publisher|
|Folders Plugin||Jenkins CI Build Monitor Plugin||Performer Enhancer Plugins||Self-Organizing Swarm Modules Plugin||GitHub Integration Plugin||Copy artifact|
Q9. Define the significance of running Selenium tests in Jenkins.
Ans. Below are some of the benefits of running the Selenium test in Jenkins:
- Whenever software is updated, it allows you to run tests and deploy it to a new environment when it passes the test
- With Jenkins, test scheduling is possible
- It will enable you to save all the execution history and test reports
- Maven is integrating with Jenkins, which helps in building and testing project with continuous integration
Q10. What is Maven?
Ans. Maven is a build management tool that works on the concept of the Project Object Model (POM). It includes Jenkins’ project information and configuration information, including:
- Construction directory
- Source directory
- Test source directory
Maven is also known as the replacement for Ant (earlier Jenkins was used Ant instead of Maven) as it overcomes issues that Ant had before.
Q11. Why is Maven with Jenkins the right combination?
Ans. Maven uses pom.xml to configure build, test, and run dependencies. It also works well in managing the entire lifecycle of the test project. Once Maven gets integrated with Jenkins, the Maven Webdriver executes all the tests and builds the project effectively.
Q12. How is Jenkins different from Maven?
Ans. Jenkins uses Maven as its build tool, helping in continuous integration. Below are the key differences:
|Continuous Integration tool||Build tool|
|Helps in software testing and reporting||Helps in build and version control|
|Introduced in 2011||Introduced in 2004|
|Plugins help in adding project written in languages other than Java||Plugins help in software build, test, source control management, running web server, etc.|
Q13. Name some of the prominent features of Jenkins.
Ans. Below are some Jenkins features:
- Free open-source tool
- Supported by the various operating system
- Pipeline support
- Fast release cycle
- Quick and easy configuration
- Supports third-party plugins
- Test harness works using JUnit
Q14. Why developers prefer using Jenkins?
Ans. Jenkins is among the prominent CI tools, and some of the benefits of using Jenkins are:
- It meets the needs of developers and has scope for continuous improvement.
- It supports various plugins that multiply the power of Jenkins.
- It is flexible with a cloud environment that helps in building cloud-native applications.
- It gives the option to define and schedule the task and builds triggers.
- It is easy to customize Jenkins as per the requirements of developers.
Q15. How does using Jenkins for Test Automation benefit developers?
Ans. Some of the benefits of using Jenkins for test automation are:
- Opens up an option for scheduling test automation.
- Developers get detailed insights on test failures.
- Gives detailed information on test results and trends.
Q16. Name some system requirements for installing Jenkins.
Ans. Below are some of the prerequisites to install Jenkins:
- RAM – 256MB
- Space – 1 GB of drive
- Language – Java
- Browser – Web browser
Q17. Which is the native scripting language used in Jenkins?
Ans. Groovy from Apache, which is a Java-based language, is used as the native scripting language in Jenkins. It improves the performance of Jenkins, and its excellent interface is dynamic and compatible.
Q18. What do you mean by Jenkins pipeline?
Ans. Several interlinked jobs places in a particular sequence are termed as a Jenkins pipeline. It includes several plug-ins that integrate and implement the delivery. There are three different types of Jenkins pipelines:
- CI (Continuous Integration)/CD (Continuous Delivery) pipeline
- Scripted pipeline
- Declarative pipeline
Q19. What is CRON?
Ans. CRON is a syntax used to schedule a Build job or SVN polling in Jenkins. It is exhibited by five asterisks separated by a space. The syntax is written in the format – Minute Hour Dom Month Dow.
Q20. What do you mean by * */1 * * *?
Ans. It means that the CRON syntax will execute the job every minute and if someone wants to implement the job every hour like at 07:00, 08:00, 09:00, and so one, one can use the syntax – 0 * * * *
Q21. Give steps for including third-party tools in Jenkins.
Ans. Below are the steps:
- Install the third-party tool
- Introduce the Jenkins module via Jenkins administrator console, which supports the tool
- Ensure to arrange the tool in the Tools Tab and Manage Jenkins area in the Jenkins administrator console
- Utilize the plug-ins from Jenkins build job
Q22. How to create global macros and templates in Jenkins job builder?
Q23. Define the steps to create backup and copy files in Jenkins.
Ans. Below are the easy steps to create backup and copy files in Jenkins:
- Periodically create the backup of “JENKINS_HOME” directory
- Use CRON job or “Thin Backup” plugin in Jenkins
- Jenkins Home directory will store all configurations
Q24. Which SCM tools are supported in Jenkins?
Ans. Below is the list of SCM tools:
Q25. Define Kubernetes.
Ans. It is a container orchestration tool used to create multiple container instances to achieve fault tolerance. This plugin can be used for ensuring continuous deploy.
These were some of the frequently asked Jenkins interview questions asked by recruiters. Also, before appearing for the interview, you must practice simple scripts and study in detail about different Jenkins plugins.