In today's tech world, DevOps is one of the hottest buzzwords. However, it is much more than just a buzzword. In this process, the development and operations teams work together to deliver products more quickly and efficiently. Recently, job listings for DevOps engineers have increased substantially. DevOps engineers are often in high demand at multinational companies like Google, Facebook, and Amazon. Even so, there are a lot of challenging topics in a DevOps engineer interview since the job market is highly competitive.

So to help you succeed as a DevOps professional, here are some of the most common DevOps interview questions that can be helpful for your preparation when interviewing for a DevOps role.

Beginners in DevOps will benefit greatly from the best DevOps tutorials.

DevOps Interview Questions

1. Who is a DevOps engineer?

Answer: A DevOps engineer commonly works with software developers and IT staff to deliver the code smoothly. Generally, they are developers who develop an interest in deployment and operations or system administrators who develop a passion for coding so they can move into development.

Shortly put, a DevOps engineer understands SDLC (Software Development Lifecycle) and automated tools that are necessary to develop continuous integration and continuous deployment pipelines.

2. Which are some of the most popular DevOps tools?

Answer: Among the most popular DevOps tools are:

• Git
• Selenium
• Jenkins
• Docker
• Chef
• Ansible
• Puppet

3. What makes DevOps so popular?

Answer: The market window for products has drastically shrunk these days. Almost every day, we see new products. The result is a multitude of choices for consumers, but it comes at the expense of heavy competition in the market. After a pause, organizations cannot afford to release big features. To keep up with this sea of competition, they ship small features as releases to their customers regularly.

The main reason why DevOps is so popular is that it allows enterprises to create and improve products much faster than traditional software development methods.

4. What is configuration management?

Answer: The purpose of configuration management (CM) is to handle changes systematically to maintain a system's integrity over time. This process involves specific policies, procedures, and tools to evaluate change proposals, manage them, and track their progress, in addition to maintaining appropriate documentation.

CM assists in the development and design of the appreciation by providing technical and administrative direction.

5. What is the use of SSH?

Answer: SSH (Secure Shell) is an administrative protocol that lets you access and control remote servers over the Internet using the command line.

In the past, there was nothing secure about Telnet, which was unencrypted. SSH is a secure encrypted version of Telnet. The communication with the remote server was encrypted as a result.

SSH also supports remote user authentication, input communication between the client and the host, and output communication between the client and the host.

6. What does CAMS stand for in DevOps?

Answer: Culture, Automation, Measurement, and Sharing (CAMS). It is the essence of what DevOps is all about.

7. What are the three important DevOps KPIs?

Answer: Listed below are a couple of DevOps KPIs:

• Meantime to failure recovery: Reducing the time it takes to recover from a failure.
• Deployment frequency: Increase the frequency of deployments.
• Percentage of failed deployments: Reduce the number of failed deployments.

8. List some of the main benefits of DevOps.

Answer: DevOps has the following core benefits:

Business benefits

• Improved delivery of features
• A stable operating environment
• Better communication and collaboration among the teams

Technical benefits

• Continuous software delivery
• Less complex management tasks.
• Defects can be detected early and corrected more quickly.

9. What is the importance of having configuration management in DevOps?

Answer: Through configuration management (CM), the team can automate time-consuming and tedious tasks, enhancing the organization's performance and agility. Also, it aids in bringing consistency and improving the process by employing design streamlining, extensive documentation, control, and change implementation during various phases and releases of a project.

10. What is Continuous Integration (CI)?

Answer: As developers work on a feature, they integrate their code into a shared repository through Continuous Integration (CI). Each integration is verified using an automated build process, so teams can identify code problems earlier than they would otherwise be able to.

11. Why is Continuous Integration needed?

Answer: With Continuous Integration for both development and testing, findings indicate that the software quality has gone up, and the time to deliver features has decreased significantly. Additionally, the development team can identify and fix errors earlier since the test cases for every commit to the shared repository are built automatically and run against the unit tests.

12. How is DevOps different from agile methodology?

Answer: Developers and operators work together in DevOps. The result is continuous development, testing, integration, deployment, and software monitoring throughout its lifecycle.

With Agile, the software is developed iteratively, incrementally, and rapidly by incorporating customer feedback at each stage. It resolves gaps and conflicts between customers and developers.

13. What is Continuous Testing (CT)?

Answer: Continuous Testing (CT) is a phase of DevOps that involves running automated test cases as part of an automated software delivery pipeline, with the sole purpose of getting immediate feedback regarding the quality of code developed by developers and validation of business risks associated with such builds. The team can use this phase to test each build continuously (as soon as the code developed is pushed), giving them a chance to get instant feedback and preventing problems from occurring later in the SDLC cycle.

Doing this would drastically speed up the workflow followed by the developer to develop the project due to the lack of manual intervention steps to rebuild the project and run the automated test cases every time the changes are made.

14. What is the role of configuration management in DevOps?

Answer:

• Manages and changes multiple systems.
• Maintains IT infrastructure by standardizing resource configurations.
• It offers administrative and management tools to manage multiple servers and ensure that the infrastructure is safe.

15. How does continuous monitoring help you maintain the entire system architecture?

Answer: In DevOps, continuous monitoring involves detecting, identifying, and reporting any faults or threats in the entire infrastructure.

• It ensures continuous auditing, transaction inspection, and controlled monitoring.
• Assures that all services, applications, and resources are functioning correctly on the servers.
• Determines whether applications are working as expected by monitoring server status.

16. Explain the term "Infrastructure as Code" (IaC) as it relates to configuration management.

Answer:

• Writing code to facilitate configuration, deployment, and automatic provisioning.
• Management of data centers with machine-readable definition files instead of physical hardware configuration.
• Consistently provisioning all your servers and infrastructure.
• The administration of cloud computing environments, commonly known as infrastructure as a service (IaaS).

17. What is the role of AWS in DevOps?

Answer: AWS plays the following role in DevOps:

• Flexible services - AWS provides ready-to-use, flexible services without having to install or set up the software.
• Automation - With AWS, you can automate tasks and processes, so you can focus on innovation.
• Secure - With AWS Identity and Access Management (IAM), you can set user permissions and policies.
• Built for scale - AWS services allow you to manage a single instance or scale up to thousands.
• Large partner ecosystem - AWS offers an ecosystem of partners who integrate and extend the AWS offerings.

18. How is IaC implemented using AWS?

Answer: You begin by defining how IaC replaces those old-fashioned techniques of putting commands into script files and testing them in an isolated environment before deployment. With the help of AWS, IaC lets developers write, test, and describe infrastructure entities using formats such as JSON and YAML, just as they do for other services. As a result, infrastructure changes can be developed and deployed efficiently.

19. What is the difference between continuous delivery and continuous deployment?

Answer:

20. What are the benefits of using the Version Control System (VCS)?

Answer: Version Control offers the following benefits:

• By using the Version Control System (VCS), all workers can access the file at any time. Additionally, all changes can be merged into a single version.
• This program helps multiple users collaborate on editing text files, makes sharing comparatively easy between various computers.
• These documents require a lot of redrafting and revision since they provide an audit trail for redrafting and updating final versions.
• All team members can access any team member's storehouse in case the central server fails.
• In the VCS, all previous versions and variants are neatly organized. It is possible to request any version at any time to get information about previously completed projects.

21. What are the different phases in DevOps?

Answer: Generally, DevOps can be divided into six phases. There is a cycle to its phases. Despite this, no phase begins until the previous one is over, and no phase can begin unless the previous one has completely ended. Let's examine the DevOps cycle phase in more detail.

1. Planning: DevOps begins with planning and software development. During this phase, participants must fully comprehend the project's ultimate work goal. Furthermore, this feeds into phases of operations and development. To have enough clarity over the project's management, it is also crucial to provide organizations with training on tools and metrics.

2. Development: During this phase, the project gets built by creating infrastructure, writing code, defining tests, or automating the process. In this phase, evidence is crucial. To manage applications, operations with data, developers store codes in code managers, which allow viewing, versioning, and much more.

3. Continuous Integration: This phase automates the validation and testing processes. There is a unique feature that ensures the development environment is good, and then it is published as a service to integrate that with the other applications.

4. Automated Deployment: The ultimate goal of DevOps is to automate deployments with tools and scripts so that the whole process becomes solved upon activation. An integral feature of this phase is the arrival of the cloud, which forces a change from finite infrastructure management to permanent cost optimization management.

5. Operations: All operations related to DevOps occur continuously throughout the life cycle of software because the infrastructure changes constantly. Platforms like this one offer opportunities for transformation, availability, and scalability.

6. Monitoring: As part of the DevOps process, this phase is permanent. The goal of DevOps is to monitor and analyze each application's current status.

22. Can you tell me something about Memcached

Answer: It's an open-source and free in-memory object caching system that's highly performant, distributed, and generic. By reducing the database load, it speeds up dynamic web applications. Here are a few applications where Memcached is useful:

• Web page caching in the content aggregation domain.
• Ad targeting profile tracking.
• E-commerce, gaming, and entertainment session caching.
• Profile caching on social networking sites like Facebook.
• Scaling and optimizing database queries to support location-based services.

23. Explain the difference between a centralized and distributed version control system (VCS).

Answer:

Centralized Version Control System:

• The versions of all files are stored on a central server
• Developers do not have a copy of all files on their local systems
• All project data will be lost if the central server crashes.

Distributed Control System:

• Each developer keeps a copy of all versions of the code on their systems.
• Allows team members to work offline and does not rely on a single location for backup.
• Even if the server crashes, there is no threat.

24. Can you list down certain KPIs which are used for gauging the success of DevOps?

Answer: KPIs stand for Key Performance Indicators. The following KPIs have become popular for measuring DevOps success:

• Automated Test Case Pass Percentage.
• Meantime to detection (MTTD)
• Customer tickets
• Meantime to recovery (MTTR)
• Error/Failure rates
• Change volume requests
• Application usage, performance, and traffic
• Application Availability
• Failed deployments
• Successful deployment frequency and time

25. What is Resilience Testing?

Answer: During resilience testing, the application is tested for its behavior under chaotic and uncontrolled conditions. Moreover, it ensures that the data and functionality are not lost in the event of a failure.

26. What is CBD in DevOps?

Answer: CBD stands for Component-Based Development. It is a unique approach to product development. Here, developers look for existing, well-defined, tested, and verified code components, so they don't have to reinvent the wheel.

27. What is the DevOps pipeline?

Answer: In general, a pipeline is a set of automated tasks/processes defined and followed by a software engineering team. The DevOps pipeline is a pipeline that enables software developers and DevOps engineers to easily rebuild, compile, and build software code that can then be deployed to production environments in an easy-to-use manner.

28. How does Ansible work?

Answer: Ansible has two types of servers, which are:

• Controlling machines
• Nodes

It requires the installation of Ansible on the controlling machine, which is also responsible for managing the nodes through SSH. In the inventories of the controlling machine, the locations of the nodes would be specified and configured.

Due to its agentless nature, Ansible does not require any installation on remote node servers. Therefore, no background process is required when managing any remote nodes.

Using Ansible Playbooks over an SSH connection, Ansible can manage many nodes from a single controlling system. Playbooks use the YAML format and can perform multiple tasks.

29. What is Git stash?

Answer: Suppose you have an unfinished project that a developer working on one branch wants to work on another branch, but you don't want to commit any changes to the unfinished work. The solution to this issue is Git stash. Git stash takes your modified tracked files and saves them on a stack of unfinished changes that you can reapply at any time.

30. Explain the concept of branching in Git.

Answer: Imagine you are working on an application, and you want to add a new feature. You can build a new feature on a newly created branch.

• You always work on the master branch by default.
• Each circle represents a commit made to the branch.
• When you are done with all the changes, merge them into the master branch.

31. How do you find a list of files that have been changed in a particular commit?

Answer: To get a list of files that have been changed in a particular commit, use the following command:

git diff-tree –r {commit hash}

• -r flag directs the command to list individual files.
• The commit hash will display all the files changed or added to that commit.

32. What is the concept behind sudo in Linux OS?

Answer: Sudo is short for ‘superuser do’ where the superuser is the root user of Linux. In Linux/Unix-based systems, this program enables root-level commands to be used by users with the superuser role.

33. Do you know about post mortem meetings in DevOps?

Answer: The purpose of post mortem meetings is to discuss certain things that went wrong while implementing DevOps methodology. As part of this meeting, the team is expected to arrive at steps that can be taken to avoid failure(s) in the future.

34. Can you explain the architecture of Jenkins?

Answer: Jenkins follows the master-slave architecture. The master pulls the latest code from the GitHub repository whenever a change is made to the code. The master requests slaves to perform operations like building, testing and running, and producing test case reports. The workload is distributed uniformly among all slaves.

Jenkins might also need to run different test suites once a commit has been made for the different environments on top of using multiple slaves.

35. What is Pair Programming?

Answer: The practice of pair programming involves two programmers working on the same design, same code, and same system. It follows the rules of "Extreme Programming". One programmer acts as the "driver" while the other acts as the "observer" to continuously monitor the project progress.

36. What is the Dogpile effect? How can it be prevented?

Answer: When huge parallel computing systems employing caching strategies are subjected to high loads, it is also referred to as a cache stampede. The event occurs when the cache expires (or is invalidated), and multiple requests are made simultaneously to a website. The most common way to prevent dogpiling is to implement semaphore locks in the cache. In this system, the first process to acquire the lock would generate the new value for the cache when the cache expires.

37. Which of the following commands runs Jenkins from the command line?

1. java – jar Jenkins.war
2. java – war Jenkins.jar
3. java – jar Jenkins.jar
4. java – war Jenkins.war

Answer: The correct answer is java –jar Jenkins.war

38. Which file is used to define a dependency in Maven?

1. build.xml
2. pom.xml
3. dependency.xml
4. Version.xml

Answer: The correct answer is pom.xml

39. How do you create a backup and copy files in Jenkins?

Answer: Back up your JENKINS_HOME directory periodically to create a backup file. Copy the JENKINS_HOME directory to create a backup of Jenkins setup. You can also clone or replicate a job directory or rename it.

40. What concepts are key aspects of the Jenkins pipeline?

Answer:

• Pipeline: User-defined model for CD pipeline. Pipelines define the complete build process, from building an application to testing it and delivering it.
• Node: A Jenkins-enabled machine capable of executing tasks.
• Step: Sets Jenkins to perform a specific task at a particular moment of time
• Stage: Defines a conceptually distinct set of tasks performed throughout the pipeline (build, test, deploy)

41. What is Jenkinsfile?

Answer: Jenkinsfiles contains the definition of Jenkins pipelines and are checked into source control. The file is text.

• The pipeline allows for code review and iteration.
• It enables a pipeline audit trail.
• Each pipeline can be viewed and edited from a single source of truth.

42. How can you copy Jenkins from one server to another?

Answer:

• You can move the job from one Jenkins installation to another simply by copying the job directory.
• Create a copy of an existing job by cloning the job directory and giving it a different name.
• Rename a directory to rename an existing job.

43. Name three security mechanisms Jenkins uses to authenticate users.

Answer:

• Jenkins stores user data and credentials in an internal database.
• Jenkins can authenticate users using an LDAP (Lightweight Directory Access Protocol) server.
• It is possible to configure Jenkins to apply the authentication mechanism used by an application server deployed.

44. How is a custom build of a core plugin deployed?

Answer: Here are the steps to deploy a custom build of a core plugin:

• Copy the .hpi file to $JENKINS_HOME/plugins.
• Remove the plugin's development directory.
• Make an empty file called .hpi.pinned.
• Restart Jenkins and run your custom build of a core plugin.

45. How can a Jenkins build be scheduled/run?

Answer:

• Manual build requests.
• Upon completion of other builds.
• Scheduled to run at a specific time.
• By source code management commits.

46. What are the commands that you can use to restart Jenkins manually?

Answer: There are two ways to manually restart Jenkins:

• (Jenkins_url)/restart // Forces a restart without waiting for builds to finish.
• (Jenkins_url)/safeRestart // Allows all running build processes to complete before restarting.

47. What can be done to temporarily disable Jenkins security if the administrative users have locked themselves out of the admin console?

Answer:

• The Config file contains an XML element named useSecurity, which is set to true when security is enabled.
• If this setting is set to false, Jenkins will automatically disable security the next time it is restarted.

48. How can you submit a form using Selenium?

Answer: The following lines of code will allow you to submit a form using Selenium:

WebElement el = driver.findElement(By.id(“ElementID”));
el.submit();

49. What is Selenium used for?

Answer: In DevOps, Selenium is used for continuous testing. It specializes in functional and regression testing.

50. What are the main benefits of DevOps automation, according to you?

Answer: DevOps automation has the following major benefits:

• Elimination of human error from the CD equation (Core benefit).
• As tasks become more predictable and repeatable, it becomes easier to identify and correct errors. As a result, it produces more reliable and robust systems.
• Eliminates bottlenecks in the CI pipeline. As a result, deployment frequency increases, and the number of failed deployments decreases. They are both important DevOps KPIs.

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If you have made it this far, then certainly you are willing to learn more about DevOps. Here are some more resources related to DevOps that we think will be useful to you.

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