Jenkins Interview Qns

1. What is continuous Integration? C.I is nothing but continuous compilation. C.I is a system which monitors fo r new changes in any version control system like svn/git, checkouts the source, builds the changes, tests the change by running corresponding test cases and dep loys it to given environment automatically (and seamlessly) without any manual i ntervention. C.I is a process or system which helps to integrate all tools and technologies r equired to move the code from development to deployment. Ideal Build and deployment workflow: check for changes | checkout | Build | Run Test cases | Deploy 2. What is the importance of C.I? Or Why we need C.I? 3. Have you created Jenkins jobs from scratch? How you create a new Jenkins Job. NewItem-->job name --> description-->select project type(free style, maven, exte rnal script, multi configurable job) --> svn url --> triggers --> Build file --> post build(emial and trigger deployment scirpt) 4. How do you install jenkins? What are the different ways of installing jenkins. - java -jar jenkins.war - yum installation (sudo service jenkins start) - deploy jenkins.war in any application server like Tomcat 5. How do you migrate Jenkins from one server to another? - install jenkins in new machine - copy .jenkins to new server - reload configurations from the disk - restart jenkins (Note: usually we don't copy workspace as it is source code and contains large s ize of data) 6. How do you start/stop/restart Jenkins? 7. What is the default port number for jenkins? How do you change the port number? 8. Where do you find Jenkins logs? 9. What challenges you faced while setting up the jenkins? 1- 1024 reserved

10. How do you find if jenkins running? 11. What is the best way or how do you stop jenkins cleanly without interrupting run ning jobs? - URL/saferestart 12. Where does jenkins store Global and job related configurations. 13. I want to change JDK for all my 1000 jobs. how do you do that? (any other config s) .jenkins/jobs/job[1..1000]/config.xml - find all config.xml files - store in an array - iterate the array using for loop - inside the for loop, use sed/awk command for find&replace - Go to jenkins and say "RELOAD CONFIGURATIONS FROM DISK" so that je nkins can load config changes. 14. How to clone Jenkins job 15. 16. How do you setup build and deployment using Jenkins for your projects? 17. How many builds you store or how do you rotate logs? what strategy you follow fo r archiving jenkins data? 18. What is parameterised build job? 19. How do you configure different jenkins jobs to run with different JDKs. 20. What is crontab and Poll scm? differences? which one you are using? why? - for compile check we use poll scm - for daily build we use, periodic build option. 21. How do you configure security for your jenkins? Are you using LDAP for authentic ation? If not why? what's the difference? Pros & Cons? 22. What is matrix based security? 23.f What is plugin? What plugins you installed? Name few plugins which you have used ? ==== 1. Thin Backup -

Using Cron tab style/notion, we can schedule the backups for jenkins. We usually take backup for Jenkins home directory. Once we install this plugin, It adds "T hinBackup" section to manage jenkins. 2. Backup Plugin Manual backup. It doesn't provide crontab kind of style for scheduling backups. we have to manually trigger the backup if we use this plugin. We usually take ba ckup for Jenkins home directory. Once we install this plugin, It adds â Backup manage r â to Manage Jenkins. 3. Parameterised Trigger Plugin: Trigger other build job on the same master by passing some env variables . 4.Inject Environment variables: If we want to pass some environment variables to downstream jobs. 5. Email-ext plugin/Editable Email notification: This is advanced plugin for Jenkins default email notifications. Using this plugin, we can create out own email subject, body and alos attach log or any file while sending the emails to users. 6. Configure History plugin: Check job configuration history like delete, configuration changes, user additio n/deletion..etc. Once we install this plugin, we can see who has done what or wh o made what changes. It records the history of all users and modifications. 7. Shelve project: If we have large size of build log files, un-used jenkins jobs, Jenkins will become slow(as it has to scan all projects for generating reports). So, It's go od idea to archive any un-used jenkins jobs so that jenkins don't scan the proje ct. since this plugin archives the projects, we can restore them if we want in t he future. ==== 24. How you install /uninstall plugins? manual plugin installation? 25. Do you back up your jenkins? how? 26. What is "Reload configurations from the Disk"? when do you use this? 27. How do you take back up for only jobs? excluding WS? 28. How do you set up distributed builds? How many slave nodes you have? What is a l abel? Label is a virtual name for one or more slave nodes using which we can tie a particular jenkins job to always run on a pariticular machine(Usually which has jdk6 or jdk8 or windows machine...etc.) 29. What are the different ways to shutdown Jenkins? 30. Have you configured Junit, Cobertura, Sonar for your builds? Have you integrated junit test cases?

ToDo: 31. Do you know how to integrate Jira with Jenkins? 32. What is build pipeline? 33. what kind of problems you faced with your jenkins so far? 34. how much you reate yourself in jenknins? 35. Do you have experience with .Net builds? what CI tools you have used for the sam e? 36. What is CI/CD model? 37. How do you setup email? have you used advanced email configuration plugin? 38. how do you upgrade jenkins? 39. 40. What is Jenkins architecture? - Jekins is java based web application - So we need to have an application server to run this - It's extensible because it's based on plug-ins 41. What is node, how do you manage nodes? 42. How do you setup Jenkins from scratch? What are the prerequisites to start Jenkins? 43. how do you deploy webapp in tomcat? 44. defference between Applicaiton and web server. 45. what is static and dynamic content