Jenkins Interview Questions For Freshers
Below is the list of interview questions for Jenkins. All questions have answers and detailed explanation with references. Follow us to stay updated with new questions:
Jenkins Interview Questions List:
- What is Jenkins?
Jenkins is a self-contained, open-source automation server that can be used to automate all sorts of tasks related to building, testing, and delivering or deploying software. Jenkins can be installed through native system packages, Docker, or even run standalone by any machine with a Java Runtime Environment (JRE) installed.
2. Tell me something about Continuous Integration, Continuous Delivery, and Continuous Deployment?
- Continuous Integration: A software development process where the changes made to software are integrated into the main code as and when a patch is ready so that the software will be always ready to be — built, tested, deployed, monitored — continuously.
- Continuous Delivery: This is a Software Development Process where the continuously integrated (CI) changes will be tested & deployed continuously into a specific environment, generally through a manual release process, after all the quality checks are successful
- Continuous Deployment: A Software Development practice where the continuously integrated (CI) changes are deployed automatically into the target environment after all the quality checks are successful
Based on the level of automation, the above three paradigms can be better represented as below -
3. What are the common use cases Jenkins is used for?
Jenkins being open-source automation can be used for any kind of software-based automation. Some of the common use-cases include but not limited to
- Software build jobs
- Sanity/Smoke/CI/Regression test jobs
- Web/Data Scraping related jobs
- Code coverage measurement jobs
- General-purpose automation
- Reverse Engineering jobs
- Key Decoding jobs & many other jobs where software automation will be
applicable.
4. What are the ways to install Jenkins?
Jenkins can be installed using -
- Native System Package Manager like — apt (Linux), brew (Mac), etc.
- Docker (popular docker images for Jenkins is available for different platforms like Unix/Mac/Windows in the docker registry)
- Kubernetes (available as a helm chart and can be installed on our Kubernetes clusters)
- Standalone (on any machine with a Java Runtime Environment installed)
5. What is a Jenkins job?
A Job/Project is the fundamental unit of a logical work (like a software build, an automation task, test execution, etc) using the Jenkins automation server and other required plugins, configurations & infrastructures.
Jobs can be of different types like — a freestyle project, a multi-configuration project, a pipeline project, a multi-branch project, etc.
6. What is a Jenkins Pipeline?
The pipeline is a special type of Jenkins job — simply a sequence of steps controlled by a defined logic — which Orchestrates long-running activities that can span across multiple build agents. It is suitable for building pipelines (formerly known as workflows) and/or organizing complex activities that cannot be easily achieved using a freestyle job.
7. What are the types of Jenkins pipelines?
Jenkins Pipelines can be either — a Declarative pipeline or a Scripted Pipeline. Declarative pipeline makes use of numerous, generic, predefined build steps/stages (i.e. code snippets) to build our job according to our build/automation needs whereas, with Scripted pipelines, the steps/stages can be custom-defined & used using a groovy syntax which provides better control & fine-tuned execution levels.
8. Explain Jenkins Multibranch Pipeline?
It is a pipeline job that can be configured to Create a set of Pipeline projects according to the detected branches in one SCM repository. This can be used to configure pipelines for all branches of a single repository e.g. if we maintain different branches (i.e. production code branches) for different configurations like locales, currencies, countries, etc.
9. How do you store credentials in Jenkins securely?
Credentials can be stored securely in Jenkins using the Credentials plugin, which stores different types of credentials like — Username with a password, SSH username with the private key, AWS Credentials, Jenkins Build Token, Secret File/Text, X509 & other certificates, Vault related credentials securely with proper encryption & decryption as and when required.
10. How can we stop a scheduled job from being executed temporarily?
Disable the job from the job details page to temporarily stop all scheduled executions & other factors/events from triggering the job and enable it back to resume the job schedules/triggers. If a job is not required permanently, we can delete the job from the jobs list view page.
Thanks for reading
Hope you find this useful. Let me know your thoughts in the comment section and don’t forget to clap if you found the article helpful. We will be releasing more questions every week. To get notified, follow us on medium.
