Jenkins Interview Questions | Part 1

Q1.  What is Jenkins ?

Ans. It is a continuous integration tool from which we can build, test, deploy application continuously and report status to project team.

Q2. What is Continuous Integration ?

Ans. Continuous Integration is a process where isolated changes are tested frequently and reported at same time. This help us to get quick feedback to Project Team to improve efficiency. 

Q3.  What is the difference between Maven and Jenkins ?

Ans. Maven is Build Automation Technology whereas Jenkins is a continuous integration tool.

Q4.  Which SCM tools Jenkins supports ?

Ans.  Jenkins can support Subversion, Git, Mercurial, Perforce, Clearcase, CVS and RTC

We need to install plugins based on our peoject requirements. In our project we are using git as    SCM tool so we are using git scm plugin in our jenkins.

Q5.  What are the various ways in which build can be scheduled in Jenkins ?

Ans. Builds can be triggered by source code management  commits. ( Poll SCM or Commit Hooks )

        Can be triggered after completion of other builds. (build other projects in post build actions)

        Can be scheduled to run at specified time ( crons )

        Manual Build Requests

Q6.  What is the relation between hudson and Jenkins ?

Ans. Hudson was the earlier name and version of current Jenkins. After some dispute with Oracle , the project name was changed from Hudson to Jenkins.

Q7.  What you do to make sure that your project build doesn't break in Jenkins ?

Ans. I make sure that I perform successful clean install on my local machine with all unit tests.

Then I make sure that I check in all code changes.

Then I do a Synchronize with repository to make sure that all required config and POM changes and any difference is checked into the repository. 

Q7.  What you do when you see a broken build for your project in Jenkins ?

Ans. I will open the console output for the build and will try to see if any file changes were missed.

If not able to find the issue that way, Will clean and update my local workspace to replicate the problem on my local and will try to solve it.

Q8. can you list out some plugins for Jenkins which are used by in your project ?

Ans. GreenBalls, Parameterise build plugin, SMTP, Maven Integrator plugin, Build Pipeline plugins, workspace clean plugin, conditional plugin, build pipeline plugin, HTML publisher plugin, dashboard view plugin

Q9. What is Poll SCM in Jenkins ?

Ans. Poll SCM is used to help us in scheduling job when ever there is new commit happened on SCM.

We can configure this setting based on our requirement. In our project we configured for 5 mins.

H/5 * * * *

Q10. How you can notify your project about build status ?

Ans. Jenkins will support multiple types of Notification channel types like Email, Slack and Microsoft team. In our project we are using SMTP plugin to send email about status of jenkins job to our peoject team.

Q11. How do you install Jenkins plugin ?

Ans: There are multiple ways to install jenkins plugin on Jenkins server.

       a)  Go to Manage Jenkins, click on Plugin management option. Under Available tab we can select the plugin which we want to use and click on install.

       b) We can copy jenkins plugin to plugins folder in Jenkins server and restart Jenkins.

       c) Go to Manage Jenkins, click on Plugin management option. Under Advaned tab we can upload plugin directly.

Q12.  How do you conigure proxy settings in Jenkins if Network is proxied in your project ?

Ans.  In our project we don’t have any proxy server configured. Incase if we want to configure, Go to Manage Jenkins, click on Plugin management option. Under Advaned tab we can configurr proxy server

Q13. How do you pass parameters from one job to another job ?

Ans. This can be done from Post build actions. We can choose Trigger Parameterized builds on other project to pass parameters to downstream job.