1. **What do you know about DevOps?**
   - Combines software development (Dev) with IT operations (Ops).
   - Aims to improve efficiency and quality of software development, delivery, and deployment.
   - Emphasizes collaboration, automation, continuous integration, delivery, and deployment.

2. **How is DevOps different from agile methodology?**
   - Agile focuses on iterative development with customer feedback.
   - DevOps focuses on collaboration between development and operations teams, emphasizing automation and continuous delivery.

3. **Which are some of the most popular DevOps tools?**
   - Selenium, Puppet, Chef, Git, Jenkins, Ansible, Docker.

4. **What are the different phases in DevOps?**
   - Plan, code, build, test, integrate, deploy, operate, monitor.

5. **Mention some of the core benefits of DevOps.**
   - Continuous software delivery, less complex problems to manage, early defect detection, faster delivery of features, improved collaboration.

6. **How will you approach a project that needs to implement DevOps?**
   - Assess existing processes, create proof of concept, implement DevOps step by step.

7. **What is the difference between continuous delivery and continuous deployment?**
   - Continuous delivery ensures code can be safely deployed but requires human approval.
   - Continuous deployment deploys every change automatically without human intervention.

8. **What is the role of configuration management in DevOps?**
   - Manages and changes multiple systems, standardizes configurations, aids in infrastructure management.

9. **How does continuous monitoring help maintain the entire architecture of the system?**
   - Detects, identifies, and reports faults or threats in the infrastructure, ensures proper functioning of services and applications.

10. **What is the role of AWS in DevOps?**
    - Provides flexible, scalable, and automated services for DevOps practices.


11. **Name three important DevOps KPIs.**
    - Meantime to failure recovery, deployment frequency, percentage of failed deployments.

12. **Explain the term "Infrastructure as Code" (IaC) as it relates to configuration management.**
    - Writing code to manage configuration, provisioning, and deployment.
    - Ensures consistent provisioning and management of infrastructure components.

13. **How is IaC implemented using AWS?**
    - Developers write infrastructure entities using formats like JSON or YAML.
    - AWS services allow for automated provisioning and management of infrastructure.

14. **Why Has DevOps Gained Prominence over the Last Few Years?**
    - Adoption by major organizations like Netflix and Facebook.
    - Accelerates application deployment, improves quality, and reduces costs.

15. **What are the fundamental differences between DevOps & Agile?**
    - Agile focuses on iterative development and customer feedback.
    - DevOps emphasizes collaboration, automation, and continuous delivery.

16. **What are the anti-patterns of DevOps?**
    - Blaming the team for inability to implement DevOps.
    - Assigning production management solely to developers.
    - Assuming DevOps is a universal solution for all organizational problems.

17. **What are the benefits of using version control?**
    - Facilitates collaboration and tracking of changes.
    - Provides version history and rollback capabilities.
    - Supports parallel development and ensures consistency.

18. **Describe the branching strategies you have used.**
    - Release branching for stable releases.
    - Feature branching for isolated feature development.
    - Task branching for individual task implementation.

19. **Can you explain the "Shift left to reduce failure" concept in DevOps?**
    - Shifts focus on security and quality to earlier stages of development.
    - Helps detect and fix issues early in the development lifecycle.

20. **What is the Blue/Green Deployment Pattern?**
    - A method for deploying updates with minimal downtime.
    - Involves swapping between two identical production environments.

21. **What is Continuous Testing?**
    - Running automated tests as part of the software delivery pipeline.
    - Provides instant feedback on business risks in the latest release.

22. **What is Automation Testing?**
    - Automating manual testing procedures using testing tools.
    - Reduces manual effort, improves accuracy, and enables repeated test execution.

23. **What are the benefits of Automation Testing?**
    - Saves time and money, enables unattended execution.
    - Supports parallel execution and reduces human errors.

24. **How to automate Testing in the DevOps lifecycle?**
    - Integrate testing into the CI/CD pipeline using automated testing tools.
    - Execute tests automatically on each code change.

25. **Why is Continuous Testing important for DevOps?**
    - Detects issues early in the development cycle.
    - Enables high-quality and frequent releases.

26. **What are the key elements of Continuous Testing tools?**
    - Test optimization, advanced analysis, policy analysis, risk assessment, service virtualization, requirements traceability.

27. **Explain the difference between a centralized and distributed version control system (VCS).**
    - Centralized VCS stores files on a central server.
    - Distributed VCS gives each developer a copy of the entire repository.

28. **What is the git command that downloads any repository from GitHub to your computer?**
    - `git clone <repository URL>`

29. **How do you push a file from your local system to the GitHub repository using Git?**
    - `git push origin master`

30. **How is a bare repository different from the standard way of initializing a Git repository?**
    - Bare repository does not contain a working directory.
    - It stores Git revision history in the root folder.

31. **Which of the following CLI commands can be used to rename files?**
    - `git mv`

32. **What is the process for reverting a commit that has already been pushed and made public?**
    - Use `git revert <commit id>` to create a new commit that undoes changes.

33. **Explain the difference between git fetch and git pull.**
    - `git fetch` downloads new data from a remote repository.
    - `git pull` updates the current branch with new changes from the remote server.

34. **What is Git stash?**
    - Saves modified files on a stack of unfinished changes.
    - Allows developers to switch to another task without committing changes.

35. **Explain the concept of branching in Git.**
    - Allows developers to work on new features or fixes without affecting the main branch.
    - Changes made in a branch can be merged back into the main branch when ready.

36. **What is the difference between Git Merge and Git Rebase?**
    - `Git merge` creates extra merge commits when integrating changes.
    - `Git rebase` incorporates changes by rewriting project history.

37. **How do you find a list of files that have been changed in a particular commit?**
    - Use `git diff-tree –r <commit hash>` to list changed files in a commit.


38. **What is a merge conflict in Git, and how can it be resolved?**
    - Occurs when merging branches with competing commits.
    - Resolved by manually editing conflicted files.
    - Can also be resolved using GitHub conflict editor or command line.

39. **What is Git bisect? How can you use it to determine the source of a regression bug?**
    - Tool using binary search to locate bug-introducing commit.
    - Mark "bad" commit where the bug occurs, "good" commit before bug.
    - Git bisect tool iterates through commits to find bug-introducing commit.

40. **Explain some basic Git commands.**
    - `git init`: Start a new repository.
    - `git config`: Set username and email for commits.
    - `git clone <repository path>`: Create local copy of existing repository.
    - `git add`: Add file(s) to staging area.
    - `git commit`: Create snapshot of staged file(s).
    - `git diff`: Show differences between branches or staged files.
    - `git status`: List files to be committed.
    - `git rm <file name(s)>`: Delete file(s) and stage changes.
    - `git show <commit>`: Show content changes and metadata of commit.
    - `git branch`: Create, delete, or list branches.


41. **Explain the master-slave architecture of Jenkins.**
   - Jenkins master pulls code from remote repository.
   - Distributes workload to Jenkins slaves.
   - Slaves execute builds, tests, and produce reports on request from master.

42. **What is Jenkinsfile?**
   - Definition of Jenkins pipeline checked into source control.
   - Text file enabling code review, audit trail, and single source of truth for pipeline.

43. **Which of the following commands runs Jenkins from the command line?**
   - A) `java –jar Jenkins.war`

44. **What concepts are key aspects of the Jenkins pipeline?**
   - Pipeline, Node, Step, Stage.

45. **Which file is used to define dependency in Maven?**
   - B) `pom.xml`

46. **Explain the two types of pipelines in Jenkins, along with their syntax.**
   - Scripted Pipeline: Groovy script-based, uses node blocks.
   - Declarative Pipeline: Simple syntax, defines pipeline block.

47. **How do you create a backup and copy files in Jenkins?**
   - Backup JENKINS_HOME directory periodically.

48. **How can you copy Jenkins from one server to another?**
   - Copy corresponding job directory.
   - Clone job directory with different name.
   - Rename existing job directory.

49. **Name three security mechanisms Jenkins uses to authenticate users.**
   - Internal database.
   - Lightweight Directory Access Protocol (LDAP) server.
   - Authentication mechanism of deployed application server.

50. **How is a custom build of a core plugin deployed?**
   - Copy .hpi file to $JENKINS_HOME/plugins.
   - Remove plugin's development directory.
   - Create empty file `<plugin>.hpi.pinned`.
   - Restart Jenkins and use custom build.

51. **How can you temporarily turn off Jenkins security if the administrative users have locked themselves out of the admin console?**
   - Set `<useSecurity>` to false in Config file.

52. **What are the ways in which a build can be scheduled/run in Jenkins?**
   - Source code management commits.
   - After completion of other builds.
   - Scheduled time.
   - Manual build requests.

53. **What are the commands that you can use to restart Jenkins manually?**
   - `Jenkins_url/restart` or `Jenkins_url/safeRestart`.

54. **Explain how you can set up a Jenkins job?**
   - New Job > Build a free-style software project.
   - Configure triggers, steps, SCM, etc.

Here are the concise bullet-point answers for the remaining questions:

55. **What are the different Selenium components?**
   - Selenium IDE: Simple framework for prototyping, easy-to-install Firefox plug-in.
   - Selenium Remote Control (RC): Testing framework for coding in any language.
   - Selenium WebDriver: Automates browser activities without relying on JavaScript.
   - Selenium Grid: Runs tests on different nodes using browsers.

56. **What are the different exceptions in Selenium WebDriver?**
   - TimeoutException: Command operation doesn't complete in stipulated time.
   - NoSuchElementException: Element with specific attributes not found.
   - ElementNotVisibleException: Element present in DOM but not visible.
   - SessionNotFoundException: WebDriver performing action after quitting browser.

57. **Can Selenium test an application on an Android browser?**
   - Yes, using an Android driver like Selendroid or Appium for native or web apps.

58. **What are the different test types that Selenium supports?**
   - Functional: Black-box testing based on software specification.
   - Regression: Finds new errors or regressions after code alterations.
   - Load Testing: Monitors response of system under load conditions.

59. **How can you access the text of a web element?**
   - Use `getText()` method of `WebElement` to retrieve text.

60. **How can you handle keyboard and mouse actions using Selenium?**
   - Use advanced user interaction API with methods like `clickAndHold()`, `dragAndDrop()`, etc.

61. **When do we use findElement() and findElements()?**
   - `findElement()`: Finds first element matching locator value.
   - `findElements()`: Finds all elements matching locator value.

62. **What are driver.close() and driver.quit() in WebDriver?**
   - `driver.close()`: Closes current browser window.
   - `driver.quit()`: Closes all browser windows and ends WebDriver session.

63. **How can you submit a form using Selenium?**
   - Use `submit()` method on the WebElement representing the form.

64. **What are the Testing types supported by Selenium?**
   - Functional Testing: Tests software functional points or features.
   - Regression Testing: Retests product after bug fixes.

65. **What is Selenium IDE?**
   - All-in-one Selenium script development environment, available as a Firefox extension.
Here are the concise bullet-point answers for the remaining questions:

66. **What is the difference between Assert and Verify commands in Selenium?**
   - Verify: Determines if a condition is true, does not halt program execution on failure.
   - Assert: Determines if a condition is true, halts program execution on failure.

67. **How to launch Browser using WebDriver?**
   - Use the respective driver instantiation:
     - `WebDriver driver = new InternetExplorerDriver();`
     - `WebDriver driver = new ChromeDriver();`
     - `WebDriver driver = new FirefoxDriver();`

68. **What is the difference between Asset Management and Configuration Management?**
   - Configuration Management:
     - Deals with operational relationships.
     - Manages troubleshooting data.
     - Concerned with deployment to retirement lifecycle.
     - Focuses on operations.
   - Asset Management:
     - Deals with incidental relationships.
     - Manages taxes data.
     - Concerned with purchase to disposal lifecycle.
     - Focuses on finances.

69. **Why are SSL certificates used in Chef?**
   - SSL certificates ensure secure communication between Chef server and clients.
   - Each node has a private-public key pair, with the public key stored at the Chef server.
   - SSL certificates validate the identity of nodes, granting access to required data.

70. **Which of the following commands would you use to stop or disable the 'httpd' service when the system boots?**
   - Correct answer: `# systemctl disable httpd.service`

71. **What is Test Kitchen in Chef?**
   - Test Kitchen is a command-line tool for spinning up instances and testing cookbooks before deploying them on actual nodes.

72. **How does chef-apply differ from chef-client?**
   - `chef-apply`: Applies a specific recipe on the client system.
   - `chef-client`: Applies all cookbooks in the server's run list to the client system.

73. **What is the command to sign the requested certificates?**
   - Puppet version 2.7:
     - `# puppetca –sign hostname-of-agent`

74. **Which open-source or community tools do you use to make Puppet more powerful?**
   - Tracked using Jira for changes, Git and Puppet's code manager app for version control, and Jenkins for continuous integration pipeline.

75. **What are the resources in Puppet?**
   - Basic units of configuration management tool, representing features of a node like software packages or services.

76. **What is a class in Puppet?**
   - Named blocks in Puppet manifests configuring functionalities of a node like services, files, and packages, executed when explicitly invoked.


77. **What is an Ansible role?**
   - An Ansible role is an independent block of tasks, variables, files, and templates embedded inside a playbook.
   - Example: A playbook that installs Tomcat on node1.

78. **When should I use '{{ }}'?**
   - Always use `{{}}` for variables, except in conditional statements like "when: …".
   - Using brackets makes it simpler to distinguish between strings and undefined variables.
   - Ensures Ansible doesn't recognize the line as a dictionary declaration.

79. **What is the best way to make content reusable/redistributable?**
   - Three ways to make content reusable/redistributable in Ansible:
     1. Use roles to manage tasks in a playbook, easily shared via Ansible Galaxy.
     2. Use "include" to add a submodule or another file to a playbook for multiple uses.
     3. Use "import" to add a file only once, helpful for recursive runs.

80. **How is Ansible different from Puppet?**
   - Ansible:
     - Easy agentless installation.
     - Based on Python.
     - Configuration files written in YAML.
     - No support for Windows.
   - Puppet:
     - Agent-based installation.
     - Based on Ruby.
     - Configuration files written in DSL.
     - Support for all popular OS's.