Do you think IIT Guwahati certified course can help you in your career?
Introduction
DevOps refers to the combination of development and operations. It's a software engineering practice that focuses on bringing together the development and operations teams with the goal of automating the project at all levels. This approach makes it simple to automate project service management so that operational goals can be met and the technology stack utilized in the production environment can be better understood.
This strategy is based on Agile methodology and stresses team collaboration, resource management, and communication. The primary advantages of employing this structure are the speed of development and resolution of problems at the production environment level, the stability of applications, and the creativity involved.
In this blog, we will discuss some of the most commonly asked Devops interview questions and their answers.
What is DevOps?
DevOps is a set of practices that combines software development (Dev) and IT operations (Ops). It aims to shorten the systems development life cycle and provide continuous delivery with high software quality. DevOps is complementary with Agile software development; several DevOps aspects came from Agile methodology.
What is a DevOps Engineer?
A DevOps Engineer is an IT professional who works with software developers, system operators, and other IT staff to oversee code releases. They are responsible for creating and implementing systems software, analyzing data, and improving existing programs. DevOps Engineers often act as a bridge between different IT teams, ensuring smooth collaboration and efficient workflows.
Cloud Platforms: Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform
Monitoring and Logging: Prometheus, ELK Stack (Elasticsearch, Logstash, Kibana), Nagios
Infrastructure as Code: Terraform, CloudFormation
Collaboration and Communication: Slack, JIRA
Scripting Languages: Python, Bash
General DevOps Interview Questions
This category will contain questions that aren't exclusive to any DevOps step. Rather than focusing on a specific tool or stage, the questions here are aimed to evaluate your comprehension of DevOps.
1. What do you know about DevOps?
Answer: In a product development process, DevOps is the grey area between development (Dev) and operations (Ops) teams. DevOps is a culture that emphasizes communication, integration, and cooperation throughout the product development cycle. As a result, it breaks down barriers between software development and operations teams, allowing them to focus on delivering products quickly and consistently.
2. Who is a DevOps engineer?
Answer: A DevOps engineer collaborates with software developers and IT personnel to guarantee that code releases go well. Developers with an interest in the deployment and operations domain, as well as system administrators with a coding enthusiasm who want to go into development.
To summarise, a DevOps engineer is someone who is familiar with the SDLC (Software Building Lifecycle) and automation technologies for the development of CI/CD pipelines.
3. What is the need for DevOps?
Answer: This response, in my opinion, should begin by describing the general market trend. Rather than providing large sets of features, firms are experimenting with how modest features might be delivered to customers via a succession of release trains. This has a number of benefits, including quicker customer feedback, higher software quality, and more customer happiness. Companies must do the following to achieve this:
Increase deployment frequency
The lower failure rate of new releases
Shortened lead time between fixes
In the event of a new release crashing, the meantime to recovery will be shorter.
4. What are the fundamental differences between DevOps & Agile?
Answer: In the table below, the distinctions between the two are listed.
Features
DevOps
Agile
Agility
Agility in both Development & Operations
Agility in only Development
Processes/ Practices
Involves processes such as CI, CD, CT, etc.
Involves practices such as Agile Scrum, Agile Kanban, etc.
Key Focus Area
Timeliness & quality have equal priority
Timeliness is the main priority
Release Cycles/ Development Sprints
Smaller release cycles with immediate feedback
Smaller release cycles
Source of Feedback
Feedback is from self (Monitoring tools)
Feedback is from customers
Scope of Work
Agility & need for Automation
Agility only
5. What are the types of HTTP requests?
Answer: The types of HTTP requests are
GET
HEAD
PUT
POST
PATCH
DELETE
TRACE
CONNECT
OPTIONS
6. What are the three important DevOps KPIs?
Answer: The following are some DevOps KPIs:
Reduce the average time it takes to recover from a failure.
Increase the frequency with which deployments take place.
Reduced Percentage of deployments that fail
7. What are the advantages of DevOps?
Answer: Some advantages of DevOps are given below
Technical benefits
Continuous software delivery
Less complex problems to manage
Early detection and faster correction of defects
Business benefits
Faster delivery of features
Stable operating environments
Collaboration and communication between teams have improved.
8. Why has DevOps gained popularity over the past few years?
Answer: DevOps is in high demand in today's economy, and many companies are keen to invest in DevOps personnel. As every significant sector hopes to see some automation in the coming years, some of the largest multi-national organizations, such as Facebook and Netflix, are spending money and time on DevOps for automation and to pace up application rollout. It aids businesses in extending and growing their operations in order to generate big revenue. Its popularity continues to rise in demand as tech rivalry grows as more organizations adopt DevOps practices; as a result, competitors must invest in similar or better development practices, raising demand.
With its new technology standards, DevOps implementation has produced demonstrable outcomes in firms that contend with better efficiency; tech professionals can deploy codes faster than ever before and with fewer errors. As a result, more consumers and organizations rely on cloud software since it demands quick deployments to fulfil customer needs without disrupting services; this has resulted in increased user adoption of cloud software such as DevOps over time.
9. What is configuration management?
Answer: Configuration management (CM) is the practice of dealing with changes in such a way that the integrity of the system is preserved throughout time. This includes rules, approaches, procedures, and tools for analyzing, managing, and tracking change proposals, as well as maintaining necessary documentation.
CM assists with administrative and technical directives for the appreciation's design and development.
10. What is SSH's purpose?
Answer: Secure Shell, or SSH, is a command-line protocol that allows users to connect to and administer remote servers over the Internet.
SSH is an encrypted version of Telnet, which was previously insecure and unencrypted. All communication with the remote server is now encrypted.
SSH includes remote user authentication, input communication between the client and the host, and client output delivery.
11. What is the significance of DevOps configuration management?
Answer: Configuration management (CM) assists the team in automating time-consuming and repetitive tasks, improving the organization's performance and agility.
By utilizing design streamlining, extensive documenting, control, and change implementation throughout the project's numerous phases/releases, also helps to ensure that the product development process is consistent and improved.
12. In DevOps, what does CAMS stand for?
Answer: Culture, Automation, Measurement, and Sharing are the acronyms for CAMS. It represents DevOps' core actions.
13. What are the various stages of DevOps?
Answer: DevOps can be divided into six stages. Its phases follow a set pattern. However, there are no boundaries between the stages, and no phase begins until the previous one has finished fully. Let's look at the DevOps cycle phase in more detail.
1. Planning The initial part of the DevOps lifecycle includes planning and software development. This phase entails thoroughly comprehending the project in order to achieve the members' final work goal. This also feeds the various development and operations phases. It's also critical that organizations receive training on tools and metrics, so that project management is clear.
2. Development
The project is constructed during this phase by creating infrastructure, writing software, defining tests, or automating processes. Evidence is crucial at this stage. Developers save programs in code managers for managing applications and data activities, which enables viewing, versioning, and much more.
3. Continuous Integration
This step automates the validation and testing mechanisms. This has a unique feature that ensures that the development environment is properly configured before being released in a service that combines it with the other apps.
4. Automated Deployment
DevOps encourages the use of tools and scripts to automate deployments, with the ultimate objective of automating the entire process with the activation of a feature. The arrival of the cloud, as a code that forces a move from finite infrastructure management to permanent cost optimization management, is the essential component of this phase.
5. Operations
All DevOps operations are often performed constantly throughout the life of software due to the dynamic nature of the infrastructure. Transformation, availability, and scalability are all possible with this platform.
6. Monitoring
This stage of the DevOps process is permanent. DevOps keeps track of and analyses data that shows the application's present state.
14. Could you explain what Memcached is?
Answer: Memcached is an open-source and free, high-performance, distributed, and generic in-memory object caching system. It's most commonly utilized to boost the performance of dynamic web applications by reducing database load.
Memcached is useful in the following situations:
Caching of profiles on social networking sites like Facebook.
Caching of the web pages in the content aggregation domain.
Ad targeting domain profile tracking
Session caching is used in the e-commerce, gaming, and entertainment domains.
In the sphere of location based services, database query optimization and scaling are important.
Memcached's Advantages:
Memcached improves application performance by lowering database hits and I/O usage.
It assists in determining which actions are performed more frequently and what to cache.
Some of the disadvantages of using Memcached are as follows:
Because it is neither a persistent data store nor a database, the data is lost in the event of a failure.
It's not a cache for certain applications.
Large items are not cacheable.
The branch name serves as the task key.
It's easy to tell which work is covered in which branch by naming the branch after the task.
15. What are the reasons why Memcached should not be used?
Answer: Some of the reasons not to use Memcached are given below:
Memcached is often mistaken for a data store rather than a cache.
Never rely on Memcached alone to gather the data you need to execute your project. A different source of data should always be available.
You can't query the data or iterate over the contents to extract information because Memcached is solely a key-value store.
There are no encryption or authentication mechanisms in Memcached.
16. How does Nagios function?
Answer: For this solution, I recommend that you read the following explanation:
Nagios is often run as a daemon or service on a server. Nagios runs plugins on the same server on a regular basis, contacting hosts or servers on your network or the Internet. The web interface can be used to view status information. If something happens, you can also be notified via email or SMS.
The Nagios daemon works like a scheduler, executing scripts at specific times. It saves the output of those scripts and runs new ones if the output changes.
17. What are Nagios Plugins?
Answer: They're command-line scripts (Perl scripts, Shell scripts, and so on) that verify the status of a host or service. The current status of hosts and services on your network is determined by Nagios using the results from Plugins.
18. Explain why we need Plugins once you've defined them.
Answer: When Nagios wants to check a host's or service's status, it will run a Plugin. The plugin will run the test and then return the results to Nagios. The results from the Plugin will be processed by Nagios, and the relevant actions will be taken.
19. What does it mean when you say Nagios is object-oriented?
Answer: The answer to this question is straightforward. "One of the advantages of Nagios is object configuration format, which allows you to build object definitions that inherit properties from other object definitions, hence the name," I'll respond. This explains and simplifies the connections between the various components."
20. What are the most widely used DevOps tools?
Answer: Some of the most popular DevOps tools are:-
Selenium
Puppet
Chef
Git
Jenkins
Ansible
Docker
21. What do you know about the DevOps pipeline?
Answer: DevOps pipeline is a continuous integration, delivery, and software deployment are made possible through an automated procedure. It includes phases like continuous integration, testing, build automation, deployment, and monitoring. The pipeline streamlines development while guaranteeing code quality, consistency, and quick delivery—essential tenets of contemporary software development processes.
22. What is the role of AWS in DevOps?
Answer: AWS (Amazon Web Services) plays a pivotal role in DevOps by providing a robust cloud platform. It provides services for networking, databases, storage, computing, and other areas. AWS is used by DevOps teams to create, launch, and grow applications, improving the speed, dependability, and effectiveness of software development and delivery procedures.
23. What are the anti-patterns in DevOps?
Answer: DevOps anti-patterns are inefficient behaviors that prevent effective development and deployment. Among them are segregated teams, a lack of automation, a disregard for feedback, and manual intervention. These procedures hinder communication between parties, bog down operations, and go against the fundamental ideas of continuous integration and continuous delivery.
24. Explain the “Shift left to reduce failure” concept in DevOps?
Answer: In DevOps, "shift left" refers to bringing testing and security audits earlier in the development cycle. As problems are identified and resolved earlier, the risk of errors and failures in later stages decreases, improving the development pipeline's efficiency and dependability.
25. Name a few useful network monitoring tools.
Answer: Some of the most popular network monitoring tools include:
Splunk
Icinga 2
Wireshark
Nagios
OpenNMS
26. What is the relationship between all DevOps tools?
Answer: A generic logical flow is shown below, in which everything is automated for flawless delivery. However, depending on the requirements, this flow may differ from one business to the next.
Developers create the code, which is then controlled using Version Control System tools such as Git.
The code is sent to the Git repository by the developers, and any modifications made to the code are committed to this repository.
Jenkins uses the Git plugin to pull this code from the repository and builds it with Ant or Maven.
Puppet and other configuration management technologies deploy and provision testing environments, and Jenkins then distributes this code to the test environment, where it is tested with tools like Selenium.
Jenkins sends the code to the production server after it has been tested (even the production server is provisioned & maintained by tools like Puppet).
It is regularly monitored after deployment using tools like Nagios.
Docker containers provide a testing environment for building features to be tested.
27. Describe the Blue-Green Deployment Method.
Answer: Blue-green deployment is a technique for reducing downtime and risk by using two identical production environments, Blue and Green. At any one time, only one of the environments is active, with the active environment handling all production traffic. Blue is currently active, whereas Green is currently inactive.
As you create a new version of your program, deployment and final testing take occur in a non-live environment, such as Green in this case. We switch the router so that all incoming requests now flow to Green instead of Blue once you've deployed and completely tested the software in Green. Green is currently active, whereas Blue is dormant.
This method can avoid application deployment downtime. Furthermore, blue-green deployment reduces risk: if something goes wrong with your new version on Green, you can switch back to Blue and roll back to the previous version.
28. What's the difference between a rolling and a blue/green deployment?
Answer: You have TWO full environments in Blue-Green Deployment. One is the current Blue environment, and the other is the Green environment to which you wish to upgrade. When you go from blue to green, the traffic is redirected to your new green environment. You can save your old blue environment as a backup until the green environment is formed.
As in Rolling Deployment, there is only ONE complete environment. The code is deployed in a subset of the same environment's instances before being relocated to another subset.
29. What Does High Availability (HA) Mean?
Answer: The ability of the application user to access the system is defined as availability. If a user is unable to access the application, it is considered unavailable. The term "high availability" refers to the application's continuous availability. Using redundant server nodes in conjunction with clustering is a common approach to improve online application availability.
Availability is sometimes represented as a percentage of annual uptime.
30. What exactly is CBD?
Answer: Component-Based Creation, or CBD, is a novel approach to product development. Instead of starting from scratch, developers use this strategy to compose and integrate existing well-defined, tested, and confirmed components into a product.
Answer: Jenkins use master-slave architecture. The master node oversees the distribution, scheduling, and monitoring of jobs. Dealing with the actual job execution are slave nodes. Using communication, the master distributes tasks to the slaves for concurrent execution. Add-ons increase functionality. Jenkins provides scalability and flexibility for automating multiple software development stages.
32. What is the Dogpile Effect? What can you do to avoid this?
Answer: When a cache expires, websites are attacked by several requests sent by the client at the same time, which is known as the dogpile effect. A semaphore lock can be used to prevent this effect. When the value in this system expires, the first process takes over the lock and begins creating fresh value.
33. What Is Sticky Session Load Balancing? What Does "Session Affinity" Mean?
Answer: Another prominent load balancing strategy is sticky session or session affinity, which requires a user session to be served by an assigned computer at all times.
In a load-balanced server application that keeps user information in sessions, it will be important to keep session data available to all computers. This can be avoided by providing a user session request from a single machine at all times. As soon as a session is created, the machine is associated with it. All requests in a given session are always forwarded to the machine connected with it. This ensures that user data is only stored on one system and that load is distributed evenly.
The SessionId cookie is commonly used for this. The cookie is provided to the client during the first request, and it must be present in every subsequent request by the client to identify the session.
34. What are the drawbacks of sticky sessions?
Answer: There are a couple of potential drawbacks with this method.
Your load balancer won't be able to tell if a request belongs to a session if the client browser doesn't support cookies. Users who do not utilize cookie-based browsers may experience weird behaviour as a result of this.
The user information (served by that machine) will be lost if one of the machines fails or goes down, and there will be no means to recover the user session.
35. What do you know about DevOps post mortem meetings?
Answer: Post-mortem sessions are held to discuss what went wrong throughout the DevOps implementation process. The team is required to come up with initiatives that need to be made in order to avoid future failures at this conference.
36. What does sudo mean in the Linux operating system?
Answer: The superuser is the Linux root user, and sudo stands for superuser do.' It is a tool for Linux/Unix-based systems that allows users with superuser roles to use root-level system commands.
37. How is DevOps different from the Agile Methodology?
Answer: DevOps supports continuous integration and delivery while focusing on communication between development and operations teams. A more comprehensive technique, agile places a focus on iterative development and client input. DevOps largely focuses on deployment and operational issues, enabling seamless delivery and maintenance. Agile works with the full software development lifecycle.
38. What is the easy way to create a tiny cloud?
Answer:VMfres is one of the most efficient ways to quickly create an IaaS cloud from Virtual Box VMs. Dokku is an excellent choice if you need a lightweight PaaS because bash scripts may be used as PaaS in Dokku containers.
39. What are your thoughts on the serverless model?
Answer: The term "serverless" refers to an architecture in which developers are unaware of the existence of servers. It means you won't have to worry about capacity, deployments, scaling, fault tolerance, or the operating system. It will effectively reduce maintenance work and allow developers to focus more on code development.
40. What types of apps are better suited to Docker Container: stateless or stateful?
Answer: For Docker Container, it is advisable to design stateless applications. We can make a container out of our application and remove the state parameters that are adjustable. We may now run the same container with varied parameters in both Production and QA environments. This enables us to reuse the same image in multiple contexts. Furthermore, a stateless application scales far more easily with Docker Containers than a stateful application.
DevOps Interview Questions for Source Code Management: Git
41. What is Git, and why is it used?
Git is a distributed version control system used for tracking changes in source code during software development. It allows multiple developers to work on a project simultaneously, manage changes efficiently, and track history. Git provides collaboration features, branch management, and merging capabilities.
42. What are the key differences between Git and SVN?
The key differences between Git and SVN are:
Git is distributed, whereas SVN is centralized.
In Git, each developer has the complete project history, while in SVN, the central repository holds the complete history.
Git allows offline commits, while SVN requires an internet connection to commit.
43. Explain the concept of a Git repository.
A Git repository is a storage location where your project’s files and history of changes are tracked. It can be local (on your machine) or remote (on a server like GitHub or GitLab). The repository stores all commits, branches, tags, and other version control information.
44. What is the difference between git fetch and git pull?
**git fetch** downloads commits, files, and refs from a remote repository into your local repository, but it doesn’t modify your working directory.
**git pull** combines git fetch and git merge, which fetches the data and automatically merges it with your current branch.
45. What is a Git branch, and why is it important?
A Git branch is a pointer to a specific commit in the project’s history. Branches are used to develop features, fix bugs, or experiment without affecting the main branch. Branches allow you to isolate changes and easily merge them back into the main codebase.
46. How do you create a new branch in Git?
To create a new branch, use the following command:
git branch <branch_name>
Then, switch to the new branch using:
git checkout <branch_name>
Alternatively, you can combine both commands with:
git checkout -b <branch_name>
47. What is a merge conflict in Git, and how do you resolve it?
A merge conflict occurs when two or more branches have conflicting changes in the same file and Git cannot automatically merge them. To resolve it, manually edit the conflicting file, removing conflict markers (<<<<<, >>>>, and =====), and commit the resolved version.
48. What is Git stash, and when would you use it?
Git stash temporarily saves changes in your working directory that are not yet committed, allowing you to switch branches without losing your progress. You can later retrieve your stashed changes using:
git stash pop
49. How do you delete a branch in Git?
To delete a local branch, use:
git branch -d <branch_name>
To delete a remote branch, use:
git push origin --delete <branch_name>
50. What is the purpose of the .gitignore file in Git?
The .gitignore file specifies files and directories that Git should ignore when committing. This is useful for excluding temporary files, configuration files, or build artifacts that should not be version-controlled.
51. What is a Git tag, and how is it different from a branch?
A Git tag is a marker used to label a specific commit, usually for release versions. Tags are static and point to a specific commit, whereas branches are dynamic and can change over time. Tags are often used to mark version releases like v1.0.
52. Explain the difference between git reset and git revert.
**git reset** moves the HEAD pointer and discards changes, potentially removing commits.
**git revert** creates a new commit that undoes the changes made by a previous commit, keeping the project history intact.
53. How can you undo a commit in Git?
To undo a commit, you can use:
git revert <commit_hash>
This creates a new commit that reverses the changes from the specified commit. Alternatively, if you want to remove the commit entirely (and it’s the latest one), use:
git reset --hard <previous_commit_hash>
54. What is Git rebase, and how does it differ from Git merge?
Git rebase moves or "rebases" your feature branch to the tip of the base branch, effectively creating a linear history. In contrast, git merge combines two branches, creating a new merge commit. Rebasing keeps the project history cleaner, while merging preserves all commit history.
55. How can you check the history of changes in a file using Git?
You can use the following command to see the history of changes in a file:
git log <file_name>
It will display all the commits that affected the specified file.
DevOps Interview Questions for Continuous Integration: Jenkins
56. What is Jenkins, and why is it used?
Jenkins is an open-source automation server used to automate parts of the software development process, like building, testing, and deploying applications. It facilitates continuous integration and continuous delivery (CI/CD) by automating tasks to ensure faster development cycles.
57. What is a Jenkins pipeline?
A Jenkins pipeline is a set of automated processes defined in a Jenkinsfile that specifies the build, test, and deployment stages of a project. It allows you to script the flow of your CI/CD process and manage it as code.
58. How do you create a pipeline in Jenkins?
You can create a Jenkins pipeline using the Pipeline plugin. Pipelines can be scripted or declarative. In the Jenkins dashboard, go to "New Item," select "Pipeline," and then define your pipeline script in the "Pipeline" section, either by writing Groovy code or using a Jenkinsfile.
59. What is the difference between Freestyle projects and Pipeline projects in Jenkins?
Freestyle projects are simple and allow you to manually configure a sequence of build steps.
Pipeline projects are defined as code, using Groovy scripting, and offer more flexibility, including version control integration and complex workflows.
60. What are Jenkins agents?
Jenkins agents (formerly known as slaves) are nodes that perform the tasks of building, testing, or deploying projects. The Jenkins master node distributes work to these agents, allowing parallel execution of jobs.
61. How can you schedule jobs in Jenkins?
You can schedule jobs in Jenkins using the "Build Triggers" section and the "Build periodically" option. Jobs can be scheduled using cron-like syntax, for example:
H/15 * * * * (every 15 minutes)
62. How do you secure Jenkins?
You can secure Jenkins by:
Enabling user authentication and role-based access control.
Configuring SSL for secure communication.
Regularly updating Jenkins and its plugins to patch security vulnerabilities.
Limiting who can access the Jenkins dashboard.
63. What are Jenkins plugins, and how do they work?
Jenkins plugins are extensions that add extra functionality to Jenkins. Plugins can add support for SCM tools like Git, allow integration with cloud services, or provide advanced job scheduling. Plugins are installed from the Jenkins Plugin Manager.
64. What is Blue Ocean in Jenkins?
Blue Ocean is a modern user interface for Jenkins, designed to simplify continuous delivery (CD) by providing a clean and intuitive pipeline visualization. It improves usability and makes the process of defining pipelines easier.
65. How do you integrate Jenkins with Git?
You can integrate Jenkins with Git by installing the Git plugin. In the job configuration, you can specify the Git repository URL, branches to build, and credentials to authenticate with the repository. Jenkins will then clone the repository and run the job.
66. What is a Jenkinsfile, and why is it used?
A Jenkinsfile is a text file that defines a Jenkins pipeline as code. It can be stored in a version control system, allowing the pipeline configuration to be versioned alongside the project code. This makes pipeline management more consistent and traceable.
67. How do you trigger a Jenkins build automatically when changes are committed to Git?
You can trigger a Jenkins build automatically using webhooks. In your Git repository (e.g., GitHub), configure a webhook to notify Jenkins when a commit is made. Jenkins will trigger the job and execute the pipeline upon receiving the webhook.
68. How do you archive artifacts in Jenkins?
Artifacts can be archived in Jenkins by configuring the "Post-build Actions" section of a job and selecting "Archive the artifacts." You can specify which files (e.g., JARs, ZIPs) should be archived for later access.
69. How do you deploy a project using Jenkins?
Jenkins can deploy a project by configuring post-build actions or pipeline steps that connect to deployment environments, such as AWS, Kubernetes, or FTP servers. You can use plugins like Deploy to Container or script your deployment using SSH or cloud APIs.
DevOps Interview Questions for Continuous Testing: Selenium
69. What is Selenium?
Selenium is an open-source tool for automating web browsers. It provides a single interface that lets you write test scripts in programming languages like Ruby, Java, NodeJS, PHP, Perl, Python, and C#, among others.
70. What are the different components of Selenium?
Selenium has four major components:
Selenium IDE (Integrated Development Environment)
Selenium RC (Remote Control)
WebDriver
Selenium Grid
71. What is Selenium WebDriver?
Selenium WebDriver is a web framework that permits you to execute cross-browser tests. This tool is used for automating web-based application testing to verify that it performs expectedly.
72. What are the advantages of Selenium?
Open-source and free
Supports multiple programming languages
Supports multiple browsers and operating systems
Has a large and active community
Allows for distributed testing
73. What is a Page Object Model (POM)?
Page Object Model is a design pattern in Selenium that creates an object repository for storing all web elements. It helps reduce code duplication and improves test maintenance.
74. How do you handle dynamic web elements in Selenium?
You can handle dynamic web elements using different locator strategies like XPath, CSS selectors, or by using explicit waits to wait for the element to be present or visible.
75. What is an implicit wait in Selenium?
An implicit wait tells WebDriver to poll the DOM for a certain amount of time when trying to find any element (or elements) not immediately available.
76. What is an explicit wait in Selenium?
An explicit wait is a code you define to wait for a certain condition to occur before proceeding further in the code. You can set up a default timeout and check for the specific condition every 500 milliseconds until the timeout occurs.
77. What is the difference between findElement() and findElements()?
findElement() returns a single WebElement.
findElements() returns a list of WebElements.
78. How do you handle alerts in Selenium?
You can handle alerts using the Alert interface. Methods like accept(), dismiss(), and sendKeys() are available to interact with the alert.
79. What is TestNG and how does it work with Selenium?
TestNG is a testing framework inspired by JUnit and NUnit. It can be integrated with Selenium to provide more powerful testing capabilities, including parallel test execution and better reporting.
80. How can you take screenshots in Selenium?
You can use the TakesScreenshot interface and its getScreenshotAs() method to capture screenshots in Selenium.
81. What is cross-browser testing and why is it important?
Cross-browser testing is the practice of testing web applications across multiple browsers to ensure consistent functionality and appearance. It's important because users may access your application using different browsers and versions.
82. How do you handle frames in Selenium?
You can switch to frames using the switchTo().frame() method. You can switch by frame index, name/ID, or by a WebElement representing the frame.
DevOps Interview Questions for Configuration Management: Chef, Puppet, Ansible
83. What is Configuration Management?
Configuration Management is the process of maintaining systems, such as computer systems and servers, in a desired state. It's a way of making sure that a system performs as it's expected to as changes are made over time.
84. What are the key differences between Chef, Puppet, and Ansible?
Chef and Puppet use Ruby for their Domain Specific Language (DSL), while Ansible uses YAML.
Chef and Puppet follow a client-server model, while Ansible is agentless.
Chef and Puppet have a steeper learning curve compared to Ansible.
Ansible is generally considered easier to set up and use, especially for smaller deployments.
85. What is idempotency in configuration management?
Idempotency means that you can apply the same configuration multiple times without changing the result beyond the initial application.
86. What is a Chef cookbook?
A Chef cookbook is the fundamental unit of configuration and policy distribution in Chef. It defines a scenario and contains everything that is required to support that scenario.
87. What is a Puppet manifest?
A Puppet manifest is a file containing Puppet code, written in Puppet's Domain Specific Language (DSL). It defines the desired state of the system.
88. What is an Ansible playbook?
An Ansible playbook is a YAML file containing a series of tasks to be executed on remote hosts. It's the core component for configuration management in Ansible.
89. How does Chef work?
Chef uses a client-server model. The Chef server stores the cookbooks, while Chef clients (nodes) pull these cookbooks and apply the configurations.
90. How does Puppet work?
Puppet also uses a client-server model. The Puppet master stores the manifests, and Puppet agents (nodes) pull and apply these configurations.
91. How does Ansible work?
Ansible works agentless, typically using SSH to connect to nodes. It pushes modules to the nodes, executes them, and removes them when finished.
92. What is a Chef recipe?
A Chef recipe is a collection of resources that describes a particular configuration or policy. It's written in Ruby and is the most fundamental configuration element within Chef.
93. What is a Puppet module?
A Puppet module is a collection of manifests and data (such as facts, files, and templates), organized around a particular purpose. It encapsulates a specific functionality.
94. What is an Ansible role?
An Ansible role is a way of organizing playbooks and other files to facilitate sharing and reuse of code. It's a higher-level abstraction of playbooks.
95. What is the purpose of Test Kitchen in Chef?
Test Kitchen is a testing harness tool used to execute your configured code on one or more platforms in isolation. It's used to automatically test cookbook data across any combination of platforms and test suites.
96. What is Hiera in Puppet?
Hiera is a key-value lookup tool for configuration data in Puppet. It helps you separate data from code, making your Puppet code more reusable.
97. What are Ansible facts?
Ansible facts are variables containing information about a system, like network interfaces or operating system. They are automatically discovered by Ansible when it runs on a host.
98. How do you handle secrets in Chef, Puppet, and Ansible?
Chef: Using encrypted data bags or Chef Vault
Puppet: Using Hiera-eyaml or Puppet's built-in encrypted SSL
Ansible: Using Ansible Vault
99. What is the difference between push and pull configuration models?
In a push model (like Ansible), the central server pushes configurations to nodes. In a pull model (like Chef and Puppet by default), nodes periodically check in with the central server for updates.
100. How do you ensure idempotency in Ansible playbooks?
Ansible modules are generally designed to be idempotent. You can also use the changed_when directive to explicitly define when a task should be considered changed.
101. What is Chef InSpec?
Chef InSpec is an open-source testing framework for infrastructure with a human-readable language for specifying compliance, security and policy requirements.
102. How does Puppet ensure consistency across different operating systems?
Puppet uses Facter, a system profiling library, to gather system information. This allows Puppet to abstract away OS differences and apply the correct configurations based on the system facts.
DevOps Interview Questions on Containerization
103. What is containerization in DevOps?
Containerization is a lightweight form of virtualization that packages an application and its dependencies into a single unit called a container. Containers are isolated environments that run consistently across various computing environments, ensuring that applications work regardless of where they're deployed.
104. What is Docker, and why is it used in DevOps?
Docker is an open-source platform used for developing, shipping, and running applications inside containers. It allows developers to bundle their application with all its dependencies, making it portable and consistent across different environments. Docker enhances DevOps by simplifying continuous integration and continuous deployment (CI/CD) processes.
105. What is the difference between a container and a virtual machine (VM)?
A container runs on a shared operating system kernel and includes only the application and its dependencies, making it lightweight and fast to start.
A virtual machine runs a full operating system and emulates hardware, leading to a larger resource footprint and slower startup times compared to containers.
106. What is Docker Compose?
Docker Compose is a tool used for defining and running multi-container Docker applications. With Docker Compose, you can define a configuration file (docker-compose.yml) that specifies the services, networks, and volumes needed to run your application, simplifying the orchestration of containers.
107. What is Docker Swarm?
Docker Swarm is Docker's native clustering and orchestration tool. It allows you to group multiple Docker hosts into a single cluster and manage containers across those hosts. Docker Swarm handles load balancing, scaling, and scheduling of containers across the cluster.
108. What is Kubernetes, and how does it differ from Docker Swarm?
Kubernetes is an open-source platform for automating the deployment, scaling, and management of containerized applications. While Docker Swarm is a native orchestration tool for Docker, Kubernetes offers more advanced features, such as self-healing, automatic rollbacks, and load balancing. Kubernetes is often preferred for large-scale, complex container orchestration.
109. How does container orchestration help in DevOps?
Container orchestration automates the deployment, scaling, management, and networking of containers. It helps in DevOps by streamlining continuous integration and continuous delivery, ensuring that containerized applications are efficiently deployed and scaled across clusters without manual intervention.
110. What are Docker images, and how are they different from containers?
A Docker image is a static file that contains the blueprint of a container, including the application code, environment variables, and dependencies. A Docker container is a running instance of a Docker image. While an image is the template, the container is the live, executable version.
111. What is the purpose of the Dockerfile?
A Dockerfile is a script containing a set of instructions to build a Docker image. It defines what the base image should be, what application to install, what commands to run, and any required configuration. Docker uses this file to automate the image creation process.
112. How can you persist data in Docker containers?
To persist data in Docker containers, you can use Docker volumes or bind mounts. Volumes store data outside the container’s writable layer, ensuring data is retained even if the container is deleted. You can define volumes in the Dockerfile or use the -v option when running a container.
DevOps Interview Questions for Continuous Monitoring
113. What is continuous monitoring in DevOps?
Continuous monitoring is the process of constantly observing the performance, security, and health of an application in real-time during production. It ensures that issues like system downtime, security breaches, or performance bottlenecks are detected and addressed promptly, maintaining system reliability.
114. What are some popular tools used for continuous monitoring in DevOps?
Some popular tools for continuous monitoring in DevOps include:
Prometheus (metrics monitoring and alerting)
Nagios (server and network monitoring)
Grafana (visualization and dashboarding)
ELK Stack (log monitoring and analysis)
Datadog (infrastructure and application performance monitoring)
115. How does Prometheus work in monitoring?
Prometheus is a time-series database used for monitoring and alerting. It collects metrics from various services by scraping endpoints and storing the data as time-stamped series. Prometheus supports queries with its own query language (PromQL), and it integrates with Grafana for visualization.
116. What is the role of Grafana in monitoring?
Grafana is an open-source tool for creating, viewing, and sharing dashboards based on data from various sources like Prometheus, Elasticsearch, and others. It allows users to visualize metrics, logs, and alerts in real-time and provides customizable dashboards for efficient monitoring.
117. What is Nagios, and how does it help in monitoring?
Nagios is an open-source monitoring tool that helps monitor the health of servers, applications, and network devices. It sends alerts when something goes wrong, such as server downtime or network issues, enabling teams to take immediate action to fix problems.
118. How can continuous monitoring improve DevOps practices?
Continuous monitoring ensures that the systems and applications are performing optimally in production. It helps in quickly identifying and addressing potential issues such as outages, security threats, and performance bottlenecks, thereby improving system reliability and minimizing downtime in DevOps environments.
119. What is the ELK Stack, and how is it used in monitoring?
The ELK Stack (Elasticsearch, Logstash, Kibana) is a popular set of open-source tools used for log aggregation, search, and visualization. It allows DevOps teams to analyze logs from various sources in a centralized location, monitor application performance, and identify issues.
120. What are the key differences between infrastructure monitoring and application monitoring?
Infrastructure monitoring focuses on monitoring physical or virtual servers, network devices, and storage, ensuring they are up and running.
Application monitoring focuses on the performance, health, and behavior of software applications, ensuring they are functioning as expected. Tools like APM (Application Performance Monitoring) are used for this purpose.
121. How can you set up alerts in a continuous monitoring system?
Alerts in a continuous monitoring system can be set up based on specific conditions, such as CPU utilization exceeding a certain threshold or a service going down. Monitoring tools like Prometheus, Nagios, or Datadog allow users to define alert rules and send notifications via email, Slack, or other channels when these conditions are met.
122. What is synthetic monitoring, and how is it different from real-user monitoring?
Synthetic monitoring uses automated scripts to simulate user interactions and measure application performance. It helps identify issues before actual users encounter them. In contrast, real-user monitoring (RUM) captures data from real user interactions to provide insights into actual application performance and user experience.
Version Control System Interview Questions
123. What is a Version Control System?
A Version Control System (VCS) is a software tool that helps track changes in source code over time. It allows multiple developers to work on the same project simultaneously, manage different versions of the code, and merge changes when necessary.
124. What are the main types of Version Control Systems?
There are two main types of VCSs:
Centralized Version Control Systems (CVCS): e.g., Subversion (SVN)
Distributed Version Control Systems (DVCS): e.g., Git, Mercurial
125. What is Git and how is it different from other VCS?
Git is a distributed version control system. Unlike centralized systems, Git gives each developer a local copy of the entire development history, and changes are copied from one repository to another. This allows for faster operations, better offline work, and more flexibility in workflow.
126. What is a repository in Git?
A repository, or "repo", is a directory that contains your project work, as well as files and folders that Git uses to track the history of changes in the project. It can be local (on your computer) or remote (on a server).
127. What is the difference between Git and GitHub?
Git is a version control system, while GitHub is a web-based hosting service for Git repositories. GitHub provides additional collaboration features like bug tracking, feature requests, task management, and wikis for every project.
128. What is a branch in Git?
A branch in Git is a lightweight movable pointer to a commit. It represents an independent line of development, allowing you to work on different features or experiments without affecting the main codebase.
129. What is a merge conflict in Git and how do you resolve it?
A merge conflict occurs when Git is unable to automatically resolve differences in code between two commits. To resolve it, you need to manually edit the files to merge the conflicting sections, then add and commit the resolved files.
130. What is the purpose of the .gitignore file?
The .gitignore file specifies intentionally untracked files that Git should ignore. This is useful for excluding files that don't need version control, such as compiled code, temporary files, or sensitive information.
131. What is Git rebase and how is it different from merging?
Git rebase is a way of moving or combining a sequence of commits to a new base commit. Unlike merging, which creates a new commit to reconcile divergent branches, rebasing replays the commits of one branch onto another, creating a linear history.
132. What is a pull request?
A pull request is a method of submitting contributions to a project. It's a way to notify team members that you've completed a feature and want to merge your changes into the main branch. It allows for code review and discussion before the merge.
Virtualization Interview Questions
133. What is virtualization?
Virtualization is the process of creating a virtual (rather than actual) version of something, such as a server, storage device, network, or operating system. It allows multiple virtual systems to run on a single physical machine.
134. What are the main types of virtualization?
The main types of virtualization include:
Server virtualization
Desktop virtualization
Network virtualization
Storage virtualization
Application virtualization
135. What is a hypervisor?
A hypervisor, also known as a Virtual Machine Monitor (VMM), is software that creates and runs virtual machines. It allows multiple operating systems to share a single hardware host.
136. What is the difference between Type 1 and Type 2 hypervisors?
Type 1 hypervisors (bare-metal) run directly on the host's hardware, while Type 2 hypervisors run on a host operating system. Examples of Type 1 include VMware ESXi and Microsoft Hyper-V, while Type 2 includes VMware Workstation and Oracle VirtualBox.
137. What are the benefits of virtualization?
Benefits include:
Improved hardware utilization
Cost savings
Easier management and maintenance
Faster provisioning of resources
Better disaster recovery
Improved scalability
138. What is a virtual machine (VM)?
A virtual machine is a software-based emulation of a physical computer. It runs its own operating system and applications as if it were a physical computer, isolating it from the underlying hardware resources.
139. What is container virtualization and how does it differ from traditional virtualization?
Container virtualization, exemplified by Docker, is a lightweight alternative to full machine virtualization. Containers share the host system's kernel and isolate the application processes from the rest of the system. They are more efficient and faster to start up than traditional VMs, but provide less isolation.
140. What is VMware vSphere?
VMware vSphere is a cloud computing virtualization platform. It's a suite of tools that includes ESXi (the hypervisor) and vCenter Server (for centralized management), allowing businesses to virtualize and manage large collections of infrastructure.
141. What is live migration in virtualization?
Live migration, also known as vMotion in VMware, is the process of moving a running virtual machine from one physical host to another without downtime. This allows for maintenance and load balancing without disrupting services.
142. What is snapshot in virtualization?
A snapshot is a point-in-time image of a virtual machine. It captures the state, data, and hardware configuration of a running VM, allowing you to revert to that state if needed. This is useful for testing and backup purposes.
DevOps MCQ Questions
143. Which of the following best describes DevOps?
A) A software development methodology
B) A collaboration between development and operations teams
C) A project management tool
D) A programming language Answer: B) A collaboration between development and operations teams
144. Which of the following Git commands is used to upload local repository content to a remote repository?
A) git pull
B) git push
C) git commit
D) git clone Answer: B) git push
145. In Jenkins, what is a "Pipeline"?
A) A sequence of jobs
B) A branch in Git
C) A container in Docker
D) A monitoring tool Answer: A) A sequence of jobs
146. What does CI in CI/CD stand for?
A) Continuous Integration
B) Continuous Iteration
C) Container Integration
D) Code Implementation Answer: A) Continuous Integration
147. Which of the following is NOT a container orchestration tool?
A) Kubernetes
B) Docker Swarm
C) Prometheus
D) Mesos Answer: C) Prometheus
148. Which Git command is used to apply changes from a remote repository to your local repository?
A) git merge
B) git commit
C) git pull
D) git branch Answer: C) git pull
149. Which tool is used for infrastructure as code in a DevOps environment?
A) Kubernetes
B) Ansible
C) Nagios
D) Jenkins Answer: B) Ansible
150. What is the main function of Docker in a DevOps pipeline?
A) Continuous monitoring
B) Version control
C) Containerization
D) Application performance management Answer: C) Containerization
151. In Prometheus, what is a "scrape"?
A) A query to extract data from logs
B) A process of pulling metrics from targets
C) An alert notification
D) A build pipeline Answer: B) A process of pulling metrics from targets
152. Which command is used to initialize a new Git repository?
A) git init
B) git status
C) git clone
D) git add Answer: A) git init
Next Steps
After reviewing these DevOps MCQ questions, the next steps would involve expanding your understanding by working on real-world DevOps projects. Practice by setting up CI/CD pipelines, deploying applications using Docker and Kubernetes, and managing infrastructure with tools like Ansible or Terraform. Continuously monitor these applications using tools like Prometheus and Grafana, and ensure you're familiar with version control workflows in Git. Building hands-on experience will solidify your knowledge and prepare you for advanced DevOps roles.
Frequently Asked Questions
Is DevOps easy or difficult?
DevOps is a philosophy, and when philosophy is turned into a job, it's not going to be simple. To meet these issues, a DevOps engineer must be multifaceted and polyvalent, and while versatility is challenging nowadays, we need cross-functional teams (and/or feature teams).
How do I prepare for a DevOps interview?
DevOps is a tough tech which takes significant time to master. To prepare for a DevOps interview, you should be familiar with its principles, such as automation, collaboration, CI/CD, IAC, etc. Further, it would be best if you learned DevOps tools, agile methodologies, and practice and practice.
What are the concepts of DevOps interview?
DevOps interviews frequently address subjects like infrastructure as code (IaC), version control, automated testing, continuous integration/continuous deployment (CI/CD), containerization, and tools like Jenkins, Docker, and Kubernetes.
What are types of DevOps?
DevOps comprises a number of essential categories, such as Infrastructure as Code (IaC), Site Reliability Engineering (SRE), Continuous Integration (CI), Continuous Delivery (CD), Continuous Deployment, and Continuous Delivery.
Conclusion
That was the most common DevOps Interview Questions list. We learned what DevOps is, how it works, and several viable implementation methods at the start of this series of DevOps courses. The DevOps interview questions in this lesson can hopefully help you ace the interview and launch a successful career in this industry.The responses to the questions are crisp and to the point. Thus, making you all ready for DevOps interview questions.
84+ registered