Top DevOps Interview Questions and Answers

By | December 17, 2021
DevOps Interview Questions and Answers

DevOps (which stands for Development and Operations) is a new methodology, practice, or a form of software development that allows the Software Development teams and the IT operations teams to collaborate and work together to create better solutions in lesser time. It is one of the hottest and the most trending buzzwords that have disrupted the development industry.

DevOps is not just a set of tools or technologies, rather than it can be thought of as a culture that most of the big tech giants are ready to adopt, if not already. It requires a pipeline of technologies that can allow the development and operations team to build a workflow to work together and bring a collaborative change.

Before the advent of DevOps, there were certain challenges faced by the IT teams and were limited to them. However, DevOps led to transparency in work and better collaboration allowing them to share and solve problems with the rest of the organization.

Currently, DevOps is at a pretty nascent stage, hence the effort required to adapt to the new technologies brought in by DevOps practices varies from company to company. However, there’s not even a hint of doubt regarding the future of DevOps since it’s expected to grow exponentially in the upcoming decade. Consequently, the demand for DevOps engineers has soared remarkably in the past several years.

If you are looking to get into the DevOps field, there are certain requirements and skills that you need to grab in your portfolio before you start hunting for a job. The most popular set of skills that organizations look out for in an ideal candidate applying for a DevOps role is –

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  • Experience in tools that allow us to automate the infrastructure such as Ansible, Puppet, Chef, etc.
  • Hands-on expertise on container orchestration and management tools like Docker, Kubernetes, etc. can be helpful.
  • Popular backend languages for programming such as Java, PHP, etc.
  • Cloud computing platforms and infrastructures such as GCP, Amazon Web Services, etc.
  • Version control and management tools like Git, BitBucket, etc.

Once you are confident that you have enough of these skills to ace any DevOps job interview with flying colors, you can move ahead and start practicing some of the most frequently asked DevOps job interview questions and answers that we have mentioned below.

Top DevOps Interview Questions and Answers

1. What can you tell me about DevOps?

Answer: DevOps (Short for Development and Operations) happens to be a newly emerging practice in the software industry. It allows organizations to build a collaborative working environment where the Development teams and the IT teams come together to build a shared pipeline for a workflow using a set of tools such as Jenkins, etc. that help them to automate the infrastructure. This allows them to carry out frequent releases with ease and efficiency. It has a self-monitoring system that allows teams to create a self-feedback loop using tools such as Prometheus, etc. Rather than thinking of DevOps as a set of tools, it can be considered as a culture allowing teams to work together resulting in CI, CD, CT, and monitoring of the application or the product throughout the lifecycle.

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2. What is the need for DevOps in the current market?

Answer:

  • There has been a cultural shift in the way companies want to release their products to their customers. They are trying to figure out a way where instead of releasing a complete finished product to the stakeholder, is there any way to release small and frequent features to the customers. The benefits that this method brings along with it are immense. This includes – quick feedback, easy to rollback, better quality, quick delivery, etc. This led to the introduction of a new practice called DevOps where the development and the IT operations teams can collaborate together to create a shared pipeline to automate the infrastructure to carry out quick and continuous development, integration, testing, and monitoring of products.
  • This allows organizations to achieve a faster average time to recover, increase the frequency of deployment, lower the failure rates, and shorten the time between fixes. The adoption of DevOps by tech giants such as Amazon, Google, etc. has resulted in unthinkable levels of performance. They are now able to deploy 1000s of modules per day without losing stability, security, quality, and reliability.

3. Explain the difference between DevOps and Agile in SDLC? (DevOps Vs Agile)

Answer:

  • Agile is a methodology frequently used in Software Development. It is a blend of iterative and incremental SDLC methodologies which primarily focus on carrying out small and frequent releases. Its purpose is to address and resolve the gaps between the developers and end-users. Agile methodologies define a set of principles guiding you on how to develop software through small and frequent releases.
  • Let’s consider a simple scenario. Suppose you have an idea or a solution to a problem and you want to develop an application or a product that addresses the problem. Now, there are several methodologies that you can adopt to carry out the development process such as waterfall model, iterative, incremental models, agile methodologies, etc. Suppose that you want to choose the agile methodology to build your product. This allows you to develop small features, test them, release them, and get feedback. Then, perform the same lifecycle iteratively to release other features as well. From a developer’s perspective, you are creating a product on a single system and are not able to collaborate with other teams to solve your problems quickly. This is where DevOps jumps in.
  • DevOps allows you to create a collaborative working environment by bringing the development and IT operations teams together to work on a shared pipeline. You can choose a set of tools that will allow several teams to work on the same product, automate the infrastructure, make service monitoring automated, and carry out frequent releases of the product with quicker feedback. To sum up, you can use the Agile methodologies as a Software development model along with DevOps practices to carry out quick and efficient releases of your product.
DevOps Agile
You can achieve small and frequent release cycles with immediate feedback. You can only achieve smaller release cycles since feedback is from en-users.
Feedback is through service monitoring tools. The end-users or customers give feedback.
You give equal priority to both quality and time. Priority is given mainly to the timely release of the product.
It brings agility in both Software Development and IT Operations teams. Agility can only be seen in the Development teams and processes.
It allows continuous deployment, development, integration, and testing. It involves practices such as Scrum, Kanban, Agile, etc.
There is a need for automation along with Agility. It focuses only on Agility.

4. List a few tools that might be handy for end-to-end DevOps.

Answer: DevOps uses a set of tools to carry out continuous development, integration, testing, deployment, and monitoring. Some of the most popular and frequently used tools in DevOps are:

  • Jenkins: It is a tool for Continuous Integration and allows you to build a pipeline where you can create multiple build jobs to distribute tasks.
  • Selenium: This tool is used for Continuous Testing and can be integrated with almost all popular programming languages.
  • Git: This is the most popular Version Control tool that allows several teams to work and manage different versions of the project.
  • Docker: It is the best containerization tool that allows creating packaged environments to build, test, and share your applications.
  • Nagios, Prometheus: These are tools used for monitoring services and providing quick feedback.
  • Ansible, Puppet, Chef: These are tools that are used to manage configuration, network, and deployment. They help in automating the infrastructure.

5. Explain how these tools work together to carry out DevOps practices?

Answer: The tools that are adopted by organizations may vary according to their requirements. However, the general flow of development used in DevOps remains the same. Let’s check it out.

  1. Development teams use Version Control tools such as Git to keep track of the code and its different versions. This is helpful in case of failure where they need to roll back a few changes.
  2. The codes and modules are kept in the git repository and whenever a change is made by anyone in any of the modules, it is pushed back to the repository and it always remains updated with the latest code.
  3. Using tools like Jenkins, this code can be pulled out from Git or other repositories such as BitBucket and with the help of other tools such as Ant, Maven, etc., the pulled code can be built.
  4. Leveraging tools for configuration management, they can deploy the testing environment and then use Jenkins to release the code on the same testing environment. Testing can be performed using automated tools like Selenium, etc.
  5. Tools such as Chef can also be used to manage the production server. Jenkins takes the code from the testing environment and deploys it to the production server.
  6. Using tools like Nagios and Prometheus, the production server can be continuously monitored and developers can get frequent reports and feedback.
  7. To test the features of the build and create a containerized testing environment, developers use container management and orchestration tools like Docker, Kubernetes, etc.

6. Enlist the advantages and benefits that DevOps brings to the table.

Answer: Performing a cultural shift from traditional development practices to a completely new methodology such as DevOps can be quite difficult, especially for large organizations. However, they are willing to go through all the hassles. This is so because the benefits that DevOps brings with it outnumber the challenge in shifting. Some of these benefits include:

  1. Continuous software delivery and frequent release.
  2. The entire workload can now be divided among both the operations and development teams.
  3. Detection of failures, bugs, and errors can be done early and resolution time is also less.
  4. It provides a stable environment for developing, testing, and production.
  5. The communication between teams is improved and provides opportunities to collaborate better.

7. What are some of the anti-patterns in DevOps?

Answer: We call a flow a pattern that tends to work generally for everyone. In some cases, common patterns work for other organizations but don’t work for you and you still follow them blindly. These patterns then become anti-patterns for you or your business. Some of the anti-patterns associated with DevOps are –

  1. Agile methodologies are the same as DevOps.
  2. We can’t adopt DevOps because we have no affordable resources for it.
  3. We don’t need DevOps because we are unique.
  4. DevOps is a release management process that is development-driven.
  5. DevOps is merely a collection of tools or a process.
  6. We will need a separate group of professionals to work on DevOps.
  7. We can solve each and every problem with the help of DevOps.
  8. Developers managing the production are called DevOps.

These are some of the myths that are associated with DevOps that need to be eradicated as quickly as possible.

8. Explain the different phases in DevOps?

Answer: There are several phases in the entire DevOps lifecycle. These phases demonstrate the end-to-end build of the product right from planning, developing to monitoring the final product. Let’s skim through these phases one at a time.

  • Planning: This phase involves studying the requirements and developing a rough plan of the development process. The requirements can be gathered by stake-holders which generally include owners, end-users, investors, etc. Once the entire blueprint is ready, you can proceed ahead.
  • Coding: As per the requirements of the end-users, the modules are coded separately and functions/procedures are defined.
  • Building: This phase includes integrating all the related modules developed in the previous phase and building the application.
  • Testing: This phase involves testing the application that was built in the previous stage, figuring out the point of failures, bugs, errors, and performing debugging. This process is repeated until all the bugs are resolved.
  • Integrating: An application is not developed by a single developer. It’s developed by a bunch of programmers and teams that work on different modules of code that carry out different functions. In this step, all these modules are integrated together.
  • Deployment: The application that has been built is deployed onto a cloud environment or a production server that can withstand high volumes of traffic.
  • Operate: In case any new changes need to be injected, operations are performed on the code making sure that it does not affect the live application.
  • Monitoring: The performance of the application is continuously monitored and detailed reports are generated and analyzed by the developers and end-users and changes are made if required.

9. Differentiate the terms Continuous Delivery (CD) and Continuous Deployment with respect to DevOps?

Answer:

Continuous Delivery Continuous Deployment
This just ensures that the code is safely deployed to the production server. This can either through manual processes or can also be done by automated processes. Each and every change that is performed on the code and that passes the automated testing process is automatically deployed to the production code.
It focuses on the business side or aspect of the product. It ensures that the applications meet the requirements and tend to work as expected. It concentrates on the development portion of the product. Developers need to make sure that the entire release process is done through frequent releases which makes it faster and efficient.
Rigorous testing is done before making any change to the production server and approvals are required for the same. The entire process is automated and approvals are not required although the entire process is carefully monitored.

10. Explain the role of Continuous Monitoring in DevOps?

Answer: Tools like Nagios, Prometheus, etc. helps us to automate and allow continuous service monitoring which is an essential component of DevOps. This is so because the entire infrastructure in DevOps is automated and approvals are not explicitly asked when making changes to the production server. Hence, continuous monitoring is very much essential to avoid any mishap. The benefits of performing Continuous Monitoring are –

  1. It helps in ensuring that the servers, resources, applications are running and communicating properly.
  2. Monitoring the status of multiple machines and servers becomes easier and getting feedback becomes quicker.
  3. Continuous audit, monitoring, and inspection can be done without any manual effort.

11. In DevOps, explain the purpose of Configuration Management (CM)?

Answer: Configuration management helps you to efficiently manage multiple systems and servers and the changes that are performed on them. It helps in creating a standardized configuration of all the prevalent resources and infrastructure which is then easier to manage. Administration of multiple servers becomes easier which in turn provides integrity to the entire system. On top of it, if the entire infrastructure is automated, tools like Jenkins, etc. can allow you to manage the infrastructure with higher degrees of efficiency.

12. Explain the role of Amazon Web Services (AWS) in DevOps?

Answer: AWS provides a cloud computing environment that is stable, secure, and easy to configure and manage. It allows businesses access to flexible resources and services which are available on-demand and they don’t need to install or set anything up to get started. It provides scalability to the entire infrastructure and you can easily scale a single instance infrastructure to thousands of services. You can choose your own nearest server to deploy your application so that you can serve your customers better. It lets you automate the entire infrastructure along with all the processes that are carried out in a typical development lifecycle. You can set your own permissions and policies using tools like identity and access management, thus making the entire infrastructure immune to attacks (internal or external). AWS is by far the most popular cloud infrastructure and has a wide share of the market, it has a large ecosystem with partners in different areas that either uses its services or provide their services to integrate with AWS.

In the domain of DevOps, AWS can be quite useful. You can deploy your entire application or infrastructure on AWS instances, integrate it with DevOps tools like Jenkins to automate the infrastructure, Git to push and pull code to and from the repositories, use AWS as the production servers, and many more.

13. Explain the phrase “Infrastructure as a Code” that is often used in DevOps?

Answer: Infrastructure as a Code in DevOps means that in order to manage deployment, the configuration of resources, and the provision of automation, you can write and develop codes. Instead of using physical hardware to manage data centers, you can simply create or use code snippets that are machine-readable. This is to ensure that it requires minimal manual intervention to monitor the servers, network resources, and other configurations; instead, everything can be done automatically, continuously, and efficiently. In short, using cloud environments to develop and maintain infrastructure is called “Infrastructure as a Code”.

14. Explain some key KPIs related to DevOps?

Answer: The main Key Performance Indicators (KPIs) related to DevOps are –

  1. The average time that is taken to recover from failures.
  2. The frequency or percentage of failures in deployments.
  3. The overall frequency or the number of times that the deployment of code to the production server takes place.

15. What is the reason behind the demand for DevOps in the past few years?

Answer: In the past few years, DevOps has been adopted by large companies such as Facebook, Netflix, etc. on a large scale. They are trying to invest heavily to shift themselves from traditional development practices to DevOps methodologies and tools. This is done to gain automation and acceleration when it centers around product development as well as its deployment. The CI, CD, CT, and CM models which allow continuous integration, monitoring, development, and testing helps these companies to develop thousands of modules within a single day. These are done without affecting the quality, security, and stability of the product. These organizations have set an example that even companies and businesses that have billions of users can quickly shift their entire infrastructure for the betterment and hence, this becomes the motivation for smaller organizations to adopt DevOps for their own day-to-day development activities.

16. What do you mean by Version Control Systems that are heavily used in DevOps?

Answer: Version Control Systems are used to manage project versions and keep records of the changes that are made in files and modules over time by different members working on the same project. It consists of a shared repository that may be centralized or distributed where the members working on the project can pull, push, and commit changes to the project files. Some of the features of Version Control Systems are –

  1. It helps us to undo the changes from the current state to a former state.
  2. You can also move back an entire project or a set of modules to any former state.
  3. You can now analyze the variations in different states.
  4. You can have the entire log of who modified the files last.
  5. Recovery from failures becomes easier.

17. Explain the two types of Version Control Systems.

Answer: In a centralized version control system, all the project files and their versions are stored in a single centralized server and no other developer has copies of the files and details regarding the versions in their own local systems. The downside is that if the centralized server fails to load or crashes for some reason, all the files are lost if there’s no backup repository.

In contrast to this, in a distributed version control system, all the developers working on the project that has access to their server have a copy of all the files and versions on their own local system. This allows all the developers to work offline and they don’t have to rely on a single point for backups of the files and versions. Even if the server fails to load, there are backups.

18. Differentiate between the pull and fetch commands in git?

Answer: Git fetch command is used to download new data and files from the respective remote repository. However, it cannot integrate or blend any new data into the files that you are working on. You can run this command at any moment to update the branches that are used for remote tracking. The command – “git fetch origin”. Instead of this, we can also use the following command – “git fetch –all”.

In contrast to this, the Git Pull command will update the head branch with all the changes you have performed lately. It downloads the new data as well as blends it with the file system that you are currently working on. In simple words, it’s used to merge the changes made locally with the ones made on the remote server. The command is – “git pull origin master”.

19. Explain branching in Git?

Answer: Let’s suppose you are working on an application on a Git repository. Now, if you wish to add a new feature or work on a different aspect of the application, you can simply create a new branch from the existing master branch. You can work on all your updates inside this new branch. Once you have committed all your changes in your new branch, you can merge them with the master branch.

20. Differentiate Git Merge with Git Rebase?

Answer: Let’s suppose you are working on a new feature on an application by creating its own branch. And simultaneously, another team member of yours creates new commits on the master branch. Now, you have two commands for your commits.

  1. The Git Merge – You can use this command to integrate the latest commits that you have made on the new feature branch with the original master branch. It will create the corresponding merge commit in the original master branch as well. However, you have duplicate commits in both the feature and original master branches now.
  2. The Git Rebase – Instead of this, you can just rebase your feature branch to the original master branch and integrate all the new commits. Now, whenever you create new commits after rebasing, it will go straight into the master branch and rewrite the history of the project.

21. Explain the advantages of VCSs?

Answer: The top benefits of VCSs such as Bitbucket, Git, etc. are –

  1. All the team members can work on the same project at a time and can access the same files simultaneously and later merge all the changes.
  2. You can get access to all the versions of the files whenever you need them and you can request any particular version and create its exact snapshot.
  3. You can get a log of all the changes made by any member on any of the files.
  4. A distributed version control system allows you to keep a copy of the files in your local machine as well so that in case, anything goes wrong in the central repository, recovery can be made easily through the backup files.

22. Mention the different branching strategies?

Answer: The three main types of branching are –

  • Feature branching: This model maintains all the changes for a particular feature and when fully tested, can be merged with the master branch.
  • Task branching: Here, each task that you work on will have its own task key and a separate branch as well.
  • Release branching: Once you have made all the necessary updates on the master branch, you can duplicate it to create a different release branch. Once such a branch is created, only fixes and other release-oriented tasks can be made in this branch and no other major changes can be done.

23. What is Master-Slave architecture in Jenkins?

Answer: The master in Jenkins is responsible for pulling the code files from the Github repository each and every time there’s a commit in the repository. It then distributes all the workload regarding the new changes to its slaves. The Jenkins master node or server communicates with the slave servers through TCP/IP protocol. Once the Jenkins master requests it, the slaves then carry out the required tests, builds, and produce reports as well.

24. Explain the process of Continuous Integration?

Answer: For every new change that the developers perform on the Github repository, they have to create a new commit to the shared version control system. The CI Jenkins master server keeps an eye on the changes and monitors them continuously. It then pulls these changes, builds them, and runs tests on them. After the tests are done, it informs that the tests have been completed and creates a report for the test. In case a fix needs to be carried out, the team fixes it and the same cycle is repeated again and again. This process is the essence of continuous integration.

25. How can you succeed in Continuous Integration?

Answer: To succeed in Continuous Integration, you should always maintain a repository for code and its backup, you can automate the build process as well as testing. You should build the commit as soon as possible and perform testing in the clone of a production environment and not in the actual environment.

26. Mention some useful plugins that you have used in Jenkins?

Answer: Some of the useful plugins that can be used with Jenkins are – Amazon EC2, Join HTML Publisher, Maven 2 Project, Copy artifact, Green balls, etc.

27. Explain a few steps that you can adopt to secure Jenkins?

Answer: You can always ensure that global security in Jenkins is always on by default. Also, always ensure that your Jenkins server is integrated with the user directory through proper plugins. You can also make sure that the project matrix is switched to fine-tune access. You should always try to limit physical access to the Jenkins server and run periodic audits for security. Always try to automate the setting of user privileges and access rights.

28. What do you mean by Continuous Testing?

Answer: In order to obtain immediate feedback, teams often execute automated tests in the pipeline on each latest build. In this way, they achieve continuous testing. This allows them to obtain quick actionable feedback so that these problems can be prevented from getting transferred to the next stage of development. As a result, product delivery speeds up since all the tests are done using automated scripts.

29. What are the key components of a Jenkins pipeline?

Answer: The key components of a Jenkins pipeline are:

  1. Pipeline: This is a user-defined and customized CD pipeline whose code defines the build process including code building, testing, and deployment.
  2. Node: It’s a server that is part of the pipeline and is responsible for executing all the processes in the pipeline.
  3. Step: It’s a task that prompts Jenkins on what to do next.
  4. Stage: It’s a subset of tasks that has to be performed in the pipeline.

30. How to create a copy of files or backups in Jenkins?

Answer: You need to create a copy of the JENKINS_HOME directory in order to periodically create backups of Jenkins. This directory contains all the information and configuration related to builds, slave nodes, and some previous history. You can copy a job directory to create the clone of a specific job.

31. How to copy or move one Jenkins Server to another?

Answer: You can simply clone the directory for the specific job from one particular server to another. You can also create a copy of a job by cloning it with another name or rename another job directory. Simply copying the directory does the job for you.

32. What is Automation Testing?

Answer: Instead of performing manual testing, we can use tools such as Selenium to create test scripts to automate the tests and even schedule them. Automation testing is generally adopted to carry out repeated tasks that gobble up a ton of useful resources in terms of both computing and man-hours. Automated Test Scripts helps us to schedule our scripts, perform tests on specific builds, create comprehensive test reports, identify the point of failure, and re-test using the same scripts again and again.

33. In DevOps, explain the steps to create automated testing plans.

Answer: Developers commit their codes in a central shared repository such as git which alerts a CI tool like Jenkins every time a new commit has been made. These new changes are then built and tested using automation testing tools like selenium which already has scripts written for the testing process.

34. Mention some of the key elements of the tools used for Continuous Testing?

Answer: Some of the key elements of the tools that are used for continuous testing are risk assessment which should cover quality assessment, risk mitigations, test optimizations, etc., policy analysis to ensure that all the tasks comply with the policies, advanced analysis with the use of automation for a scope assessment, code, and impact analysis, test optimization for proper management and maintenance, and other elements such as requirements traceability, service virtualization, etc.

35. Explain the elements of Selenium Testing.

Answer: The key components of Selenium Testing are –

  • Selenium IDE is a framework and creates a perfect environment with plugins to develop test scripts.
  • Selenium Remote Control allows developers to write code and scripts in any language.
  • Selenium WebDriver allows you to automate browser activities by simulating the browser experiences.
  • Selenium Grid is used to run tests on different computer nodes while working with browsers.

36. What testing types can Selenium support?

Answer: Selenium can support the following testing types –

  • Regression Testing – It helps to find out errors and bugs that can be introduced as a result of adding new features or pieces of code to the existing modules.
  • Functional Testing – It’s based on the functional requirements of the software and is specific to the functions and capabilities of the software.
  • Load Testing – This type of testing is used to find out how the application performs on putting the load on it.

37. List the goals of Configuration Management?

Answer: The main goal of Configuration Management is to make the entire development life cycle configurable, controllable, and manageable so that a higher-quality product is created. Its goals include –

  1. Improving the performance.
  2. Extending the life of the product.
  3. Reducing risk, cost, and liabilities.
  4. Make the process reliable and maintainable.
  5. Revise the capability.

38. What is Puppet and explain its architecture?

Answer: Puppet is a DevOps tool used widely for configuration management. It is also used to automate certain administrative tasks. Puppet has a typical master-slave architecture where the slave requests a certificate to the master node and the master signs it which states that the connection has been established. The slave sends requests to the master puppets which then pushes the configuration to the slaves. To automate the authentication that a client node has to perform with the master puppet, we can enable auto sign in the puppet configuration file.

39. Explain the difference between puppet modules and manifests.

Answer: Every puppet agent also called puppet nodes has its own configuration written in the puppet language. These are called puppet manifests that have the .pp extension. You can define a puppet module as just a set of these manifests. It might also include other pieces of data such as templates, related files, facts, etc. with a particular structure of the directory. Modules help us to split our puppet code into multiple manifests and organize them in a better way.

40. What is the use of the Chef tool?

Answer: The Chef is a potent tool for automation often employed to transform infrastructure to code. It is used to write scripts to automate processes.

41. Explain the entire architecture (in simpler terms) of the automation tool Chef.

Answer: The chef tool consists of 3 main elements. The first one is the Chef Server which acts as a central repository to store the configuration data. These data include node configurations, etc. The second one is the Chef Node which can be any host which has been configured to use the chef-client. It can reach the Chef server to get all the data needed to configure and set up the nodes. The final one is the Chef Workstation which is used to update the cookbooks and other sensitive configuration data.

42. What are Chef resources?

Answer: A Resource is a part of the infrastructure and can be a package, a service, or simply a file. The functions of a chef resource include :

  1. It is used to describe the state of a configuration component.
  2. It also defines the steps needed to bring that particular component to the state it wants to be in.
  3. Specifies a type such as a file, package, or template.
  4. Lists details such as properties, etc.
  5. They are grouped into packets or recipes describing the configurations.

43. Differentiate Cookbooks and Recipes from the Chef?

Answer: A Recipe in Chef is a set of resources that represents configurations related to a package, template, file, or any other piece of infrastructure. Cookbook groups all the related recipes and other files that are linked to the recipe. This helps them to facilitate the reusability and accessibility of configuration files.

44. What is an Ansible module?

Answer: Each module in Ansible can be written using any popular scripting language and is considered to be the basic and standalone unit of work. They are idempotent which means that even if any operation is repeated multiple times, it will bring back the system to the same place.

45. What are Ansible Playbooks?

Answer: Ansible playbooks define the general language for configuration, orchestration, and tasks related to deployment as well. They can help you to describe a policy that has to be enforced by your remote systems or simply a set of steps. They are human-readable and their basic use is to manage all the configurations of the remote machines along with the deployments.

46. What’s the use of Continuous Monitoring?

Answer: The main goals of Continuous Monitoring are audit, controls monitoring, and inspection of transactions at frequent intervals. This allows us to identify the problems in a timely manner and helps us to decide the appropriate action to be taken which reduces the expenses of the organizations.

47. What is Nagios?

Answer: Nagios is a popular tool used for Continuous Monitoring of services, applications, processes, systems, etc. Nagios can alert the staff in case of failures so that they can take appropriate measures which won’t cost anything to the business stakeholders. Nagios can be used to:

  1. Respond to issues with a perfect solution at the first sign.
  2. Plan for upgrades in the infrastructure before a system gets outdated and stops working.
  3. Fix problems automatically on the detection and ensure that all the SLAs are met.
  4. Monitor the infrastructure and provide timely reports to the staff.

48. Explain the working of Nagios?

Answer: Nagios typically runs on a server with the help of a daemon or a service and runs plugins on the same server and connects several hosts on the network. We can view the status of all the hosts through a web UI and receive alerts through notifications. The daemon acts as a scheduler that can run appropriate scripts when required.

49. What are containers and what are their advantages over virtualization?

Answer: Containers are packaged environments that run on the host OS, isolated from other containers. They allow you to develop, build, test, deploy, and share applications all within a packaged environment that contains its own filesystem, libraries, and binary files.

It’s better than using VMs because it takes up low resources as it runs on the underlying host’s OS whereas VMs require the hardware of the host it runs on. Containers are very less in size and hence faster than VMs.

50. Explain Docker Images, Containers, Docker Hub, and Dockerfile.

Answer: Docker helps you to run applications in the packaged environment called Containers. These containers run on the underlying host machines and are isolated from other containers running from the same machine.

A Docker image can be viewed as the blueprint for the Docker container that it creates. In other words, Docker Images contains all the rules, instructions, and steps to be performed while creating an instance of it which are actually called Docker containers. In simpler words, Docker Images are predefined templates and can be customized to create containers with desired capabilities, libraries, and packages. Inside these containers, you can develop your own application and even deploy them.

Docker Hub is Docker’s official registry which contains tons of official images such as Alpine, Ubuntu, CentOS, MySQL, etc. that you can pull directly and use as a base image to create your own customized images over it.

A Dockerfile is used to create a customized docker image. You can define instructions such as FROM instruction to use a specific base image, RUN instruction to execute specific commands when the image is built, USER instruction to specify a default user when a container is run associated with the image using the docker run command, etc. In other words, Dockerfile is the blueprint of your docker images.

Wrapping Up!

In this guide, we discussed the top DevOps interview questions that are most frequently asked. We covered all the aspects of DevOps starting from the introduction of DevOps and moving forward to advanced topics such as Version Control Systems like Git, Continuous Integration and its tools like Jenkins, Continuous Testing tools like Selenium, Continuous Monitoring tools like Nagios, and Continuous Management tools like Ansible, Puppet, and Chef. We skimmed through some important questions on these tools including their use, benefits, architectures, etc. In the end, we also discussed containerization technologies such as Docker and its components.

We certainly hope that this guide helps you to revise all the concepts of DevOps and its tools before you start hunting for Job Interviews and ace them with flying colors.

Happy Learning!

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