DevOps Interview Questions

Delve into the domain of DevOps Interview Questions, where the primary focus of a DevOps Engineer is to refine and elevate the software development lifecycle. This involves ensuring a seamless and efficient transition from code development to production deployment. The role necessitates collaborative efforts with both development and operations teams to automate repetitive tasks, institute continuous integration and delivery (CI/CD) pipelines, and enhance the overall reliability of the system.

DevOps Interview Questions

If you’re gearing up for a DevOps Engineer job interview, being well-prepared is crucial. It can give you a competitive advantage and boost your chances of receiving a favorable response. This article provides you with the most frequently asked questions during the interview.

Q1. What is the use of SSH?
SSH(Secure Shell) is an access credential used in the SSH Protocol. In other words, it is a cryptographic network protocol that transfers encrypted data over the network. It allows you to connect to a server, or multiple servers, without having to remember or enter your password for each system that is to log in remotely from one system to another.

Q2. What is CI/CD?
CI And CD is the practice of automating the integration of code changes from multiple developers into a single codebase. It is a software development practice where the developers commit their work frequently to the central code repository (Github or Stash). 

Continuous Integration
With Continuous Integration, developers frequently commit to a shared common repository using a version control system such as Git. A continuous integration pipeline can automatically run builds, store the artifacts, run unit tests, and even conduct code reviews using tools like Sonar.

Continuous Delivery
Continuous delivery helps developers test their code in a production-similar environment, hence preventing any last-moment or post-production surprises. These tests may include UI testing, load testing, integration testing, etc. It helps developers discover and resolve bugs preemptively.

Q3. What is Hypertext Transfer Protocol Secure(HTTPS)?
Hypertext Transfer Protocol Secure is a protocol that is used to communicate between the user browser and the website. It also helps in the transfer of data. It is the secure variant of HTTP. To make the data transfer more secure, it is encrypted. Encryption is required to ensure security while transmitting sensitive information like passwords, contact information, etc. 

Q4. What is the Blue/Green Deployment Pattern?
Blue Green Deployment is just like we deploy two versions of our application, one is the stable version, and another is a new feature or bug fix let’s say, forwarding a certain percentage of traffic to the second version as well in production to ensure that everything is working fine.

Blue Deployment
It’s the primary Deployment that is stable, and being used as production.

Green Deployment
It’s a kind of clone version, but it has additional changes in it, we can route the traffic to the Green deployment so that if any issues are there in the Deployment we can fix them and then promote it to Blue, so that reducing the chances of failures in production environment.

Q5. What’s the difference between DevOps & Agile?

Q6. What is the continuous testing process?
Continuous testing is a process of automated testing done on software continuously as soon as a piece of code is delivered by the developers. This testing is done at every stage starting from the initial stages of development until the deployment of software.

Q7. What is ‘Pair Programming’?
Pair programming is a development technique in which two programmers work together at a single workstation. A person who writes code is called a driver and a person who observes and navigates each line of the code is called a navigator. They may switch their role frequently.

Q8. What is the DevOps life cycle?
DevOps Lifecycle is the set of phases that includes DevOps for taking part in Development and Operation group duties for quicker software program delivery.DevOps follows positive techniques that consist of code, building, testing, releasing, deploying, operating, displaying, and planning. DevOps lifecycle follows a range of phases such as non-stop development, non-stop integration, non-stop testing, non-stop monitoring, and non-stop feedback. 7 Cs of DevOps are:

• Continuous Development
• Continuous Integration
• Continuous Testing
• Continuous Deployment/Continuous Delivery
• Continuous Monitoring
• Continuous Feedback
• Continuous Operations

Q9. What do you mean by Configuration Management?
The process of controlling and documenting change for the development system is called Configuration Management. Configuration Management is part of the overall change management approach. It allows large teams to work together in s stable environment while still providing the flexibility required for creative work. 

Q10. What is Infrastructure as Code (IaC)?
Infrastructure as Code (IaC) is a method of managing and provisioning IT infrastructure using code, rather than manual configuration. It allows teams to automate the setup and management of their infrastructure, making it more efficient and consistent. This is particularly useful in the DevOps environment, where teams are constantly updating and deploying software.

Q11. What’s the difference between DataOps and DevOps?

Q12. Explain the concept of branching in Git.
Branching means diverging from the mainline and continuing to work separately without messing with the mainline. Nearly every VCS has some form of branch support. In Git, a branch is simply a reference to the commit, where the following commits will be attached. 

Q13. What is Git stash?
The Git stash command can be used to accomplish this if a developer is working on a project and wants to preserve the changes without committing them. This will allow him to switch branches and work on other projects without affecting the existing modifications. You can roll back modifications whenever necessary, and it stores the current state and rolls back developers to a prior state.

Q14. What is a GIT Repository?
Repositories in GIT contain a collection of files of various versions of a Project. These files are imported from the repository into the local server of the user for further updations and modifications in the content of the file. A VCS or the Version Control System is used to create these versions and store them in a specific place termed a repository.

Q15. What is Component-Based Model (CBM) in DevOps?
The component-based assembly model uses object-oriented technologies. In object-oriented technologies, the emphasis is on the creation of classes. Classes are the entities that encapsulate data and algorithms. In component-based architecture, classes (i.e., components required to build application) can be uses as reusable components.

Q16. What is Dogpile effect?
Cache Stampede or Dogpile Problem in System Design is a phenomenon that can occur in systems that rely on caching to improve performance. As a result, the system experiences a sudden surge in demand, often overwhelming the backend resources and causing a performance degradation.

Q17. What Is Jenkins?
Jenkins is a tool that is used for automation, and it is an open-source server that allows all the developers to build, test and deploy software. It works or runs on java as it is written in java. By using Jenkins we can make a continuous integration of projects(jobs) or end-to-endpoint automation.

Q18. How to Make a CI-CD Pipeline in Jenkins?
DevOps professionals mostly work with pipelines because pipelines can automate processes like building, testing, and deploying the application. With the help of Continuous Integration / Continuous Deployment (CI/CD) Pipeline scripts we can automate the whole process which will increase productivity save lots of time for the organization and deliver quality applications to the end users.

Q19. What is the use of the cherry-pick command in git?
Git cherry-pick in git means choosing a commit from one branch and applying it to another branch. This is in contrast with other ways such as merge and rebases which normally apply many commits into another branch.

The command for Cherry-pick is as follows: 

git cherry-pick<commit-hash>

Q20. What is sudo command in Linux?
Sudo (Super User DO) command in Linux is generally used as a prefix for some commands that only superusers are allowed to run. If you prefix any command with “sudo”, it will run that command with elevated privileges or in other words allow a user with proper permissions to execute a command as another user, such as the superuser. This is the equivalent of the “run as administrator” option in Windows.

Q21. What’s the Difference Between Git Fetch and Git Pull ?

Q22. What are the components of Selenium?
Selenium is a powerful tool for controlling web browser through program. It is functional for all browsers, works on all major OS and its scripts are written in various languages i.e Python, Java, C#, etc, we will be working with Python. Selenium has four major components :-

• Selenium IDE
• Selenium RC
• Selenium Web driver
• Selenium GRID

Q23. What is a Puppet in DevOps?
Puppet is an open-source configuration management automation tool. Puppet permits system administrators to type in infrastructure as code, using the Puppet Descriptive Language rather than utilizing any customized and individual scripts to do so.This means in case the system administrator erroneously alters the state of the machine, at that point puppet can uphold the change and guarantee that the framework returns to the required state. 

Q24. What is Ansible?
Ansible is an open-source IT engine that automates application deployment, cloud provisioning, intra-service orchestration, and other IT tools.Ansible can be used to deploy the software on different servers at a time without human interaction. Ansible can also be used to configure the servers and create user accounts. Ansible is an agent-less software which means there is no need to install the software in the nodes which means you need to do the SSH to connect the nodes to perform the required operations on the servers.

Q25. What’s the difference between Chef and Puppet?

Q26. What is Automation Testing?
Automated Testing is a technique where the Tester writes scripts on their own and uses suitable Software or Automation Tool to test the software. It is an Automation Process of a Manual Process. It allows for executing repetitive tasks without the intervention of a Manual Tester.

Q27. What is Git Rebase?
Rebasing in Git is a process of integrating a series of commits on top of another base tip. It takes all the commits of a branch and appends them to the commits of a new branch.The main aim of rebasing is to maintain a progressively straight and cleaner project history. Rebasing gives rise to a perfectly linear project history that can follow the end commit of the feature all the way to the beginning of the project without even forking. This makes it easier to navigate your project.

The technical syntax of rebase command is:

git rebase [-i | --interactive] [ options ] [--exec cmd] [--onto newbase | --keep-base] [upstream [branch]]

Q28. What is the importance of continuous feedback in DevOps?
Continuous Feedback in software testing is trying out an iterative process that involves presenting everyday comments, reviews, and critiques during the software program improvement lifecycle. It ensures that builders get an equal message approximately the quality and functionality of their code. Let’s delve deeper into this concept little by little and discover the variations associated with it.

Q29. What is Selenium Tool Suite?
Selenium is a very well-known open-source software suite, mainly used for testing web browsers and web applications by automating some processes. It comes with a set of tools and libraries that allow developers or testers to automate some functions related to web browsers and web applications.Selenium Tool suite consists of 4 major components:

• Selenium IDE (Integrated Development Environment)
• Selenium WebDriver
• Selenium Grid
• Selenium Remote Control (Deprecated)

Q30. What is Selenium IDE?
Selenium IDE (Integrated Development Environment) is an open-source web testing solution. Selenium IDE is like a tool that records what you do on a website. Subsequently, these recorded interactions can be replayed as automated tests. You don’t need much programming skills to use it. Even if you’re not great at programming, you can still make simple automated tests with it.

Q31. What is Git Bash?
Git Bash is a command-line interface (CLI) application for Windows that lets you communicate with Git, the version control system. Clone the repositories, commit changes, push and pull changes, and more are all possible using Git Bash. Git Bash can automate manual tasks with the scripts written by you. Git Bash helps you in a greater way to learn about Git and version control.

Q32. What is Git Squashing?
Squashing combines multiple commits into a single commit based on your commit history. With the help of squashing you can clean your branch history and can maintain an organized commit timeline. It is used before pulling requests or merging feature branches.

Q33. What is a merge conflict in Git?
Merge Conflicts are the conflicts that occur when a developer is editing a file in a particular branch and the other developer is also editing that same file or when developer A edits some line of code and that same line of code is being edited by another developer B that leads to conflicts while merging.

Q34. What is Git prune?
Git prune is a command that deletes all the files that are not reachable from the current branch. The prune command is useful when you have a lot of files in your working directory that you don’t want to keep. The primary use of git prune is to clean up your working directory after you have finished working on a project. What actually git prune does is, suppose you have an object or commit that is no longer reachable from the current branch.

Command:

git fetch –prune <remote>

Q35. What is Banker’s Algorithm in OS?
The banker’s algorithm is a resource allocation and deadlock avoidance algorithm that tests for safety by simulating the allocation for the predetermined maximum possible amounts of all resources, then makes an “s-state” check to test for possible activities, before deciding whether allocation should be allowed to continue.

Q36. What’s the difference between HTTP and HTTPS ?

Q37. Explain the “Shift left to reduce failure” concept in DevOps?
In DevOps, “shift left” means bringing testing and security audits earlier in the development cycle. Problems are recognized and resolved early, which reduces the likelihood of errors and failures in subsequent phases, boosting the efficiency and dependability of the development pipeline.

Q38. What are Virtual machines (VMs) ?
Virtual Machine abstracts the hardware of our personal computer such as CPU, disk drives, memory, NIC (Network Interface Card) etc, into many different execution environments as per our requirements, hence giving us a feel that each execution environment is a single computer. For example, VirtualBox.

Q39. What is the difference between Git Merge and Git Rebase?

Q40. What is a bare repository?
A bare repository is the same as default, but no commits can be made in a bare repository. The changes made in projects cannot be tracked by a bare repository as it doesn’t have a working tree. A working tree is a directory in which all the project files/sub-directories reside. Bare repository is essentially a .git folder with a specific folder where all the project files reside.