Here is a compilation of 100 frequently asked DevOps interview questions and answers:

1. What is DevOps?
   DevOps is a software development methodology that combines software development (Dev) with IT operations (Ops) to shorten the development lifecycle and provide continuous delivery of high-quality software.
2. What are the key principles of DevOps?
   Key principles include collaboration, automation, continuous integration, continuous delivery, and continuous monitoring.
3. What is continuous integration (CI)?
   CI is the practice of frequently merging code changes into a central repository, followed by automated builds and tests.
4. What is continuous delivery (CD)?
   CD is the practice of automatically preparing code changes for release to production after passing automated tests.
5. What is infrastructure as code (IaC)?
   IaC is the practice of managing and provisioning infrastructure through code instead of manual processes.
6. What are some common DevOps tools?
   Common tools include Jenkins, Git, Docker, Kubernetes, Ansible, and Terraform.
7. What is the role of automation in DevOps?
   Automation is crucial in DevOps for streamlining processes, reducing errors, and enabling faster and more frequent releases.
8. What is version control?
   Version control is a system that records changes to files over time, allowing you to recall specific versions later.
9. What is Git?
   Git is a distributed version control system for tracking changes in source code during software development.
10. What is a Git repository?
    A Git repository is a directory that contains your project work, as well as files and folders that Git uses to track changes.
11. What is a branch in Git?
    A branch in Git is a lightweight movable pointer to a commit, allowing for parallel development.
12. What is a pull request?
    A pull request is a method of submitting contributions to a project, typically used in Git-based platforms like GitHub.
13. What is Docker?
    Docker is a platform for developing, shipping, and running applications in containers.
14. What is a container?
    A container is a lightweight, standalone, executable package that includes everything needed to run a piece of software.
15. What is Kubernetes?
    Kubernetes is an open-source container orchestration platform for automating deployment, scaling, and management of containerized applications.
16. What is a Kubernetes pod?
    A pod is the smallest deployable unit in Kubernetes, consisting of one or more containers that share storage and network resources.
17. What is Ansible?
    Ansible is an open-source automation tool used for configuration management, application deployment, and task automation.
18. What is Terraform?
    Terraform is an open-source infrastructure as code software tool that enables defining and provisioning infrastructure using a declarative language.
19. What is Jenkins?
    Jenkins is an open-source automation server used to build, test, and deploy software projects continuously.
20. What is a Jenkins pipeline?
    A Jenkins pipeline is a suite of plugins that supports implementing and integrating continuous delivery pipelines into Jenkins.
21. What is blue-green deployment?
    Blue-green deployment is a technique for releasing applications by shifting traffic between two identical environments running different versions of the application.
22. What is canary deployment?
    Canary deployment is a technique where a new version of an application is gradually rolled out to a small subset of users before being deployed to the entire infrastructure.
23. What is configuration management?
    Configuration management is the process of maintaining systems, such as computer systems and servers, in a desired state.
24. What is Puppet in DevOps?
    Puppet is a configuration management tool that helps in automating the provisioning and management of IT infrastructure.
25. What is Chef in DevOps?
    Chef is a configuration management tool that automates the process of managing servers and applications.
26. What is monitoring in DevOps?
    Monitoring in DevOps involves tracking the performance and health of applications, services, and infrastructure to ensure they are functioning correctly.
27. What is logging in DevOps?
    Logging in DevOps involves recording events, errors, and other relevant information to help troubleshoot issues and understand system behavior.
28. What is Prometheus?
    Prometheus is an open-source monitoring and alerting toolkit designed for reliability and scalability.
29. What is Grafana?
    Grafana is an open-source platform for monitoring and observability that allows you to query, visualize, and alert on metrics.
30. What is ELK stack?
    ELK stack refers to Elasticsearch, Logstash, and Kibana, which together provide a powerful platform for log management and analysis.
31. What is a microservices architecture?
    Microservices architecture is an approach to developing software systems as a suite of small, independently deployable services.
32. What is service discovery in microservices?
    Service discovery is the process of automatically detecting devices and services on a network.
33. What is a load balancer?
    A load balancer distributes incoming network traffic across multiple servers to ensure no single server becomes overwhelmed.
34. What is auto-scaling?
    Auto-scaling is the process of automatically adjusting the number of computational resources based on the load.
35. What is chaos engineering?
    Chaos engineering is the practice of intentionally introducing failures in a system to test its resilience and identify weaknesses.
36. What is GitOps?
    GitOps is a way of implementing Continuous Deployment for cloud native applications using Git as a single source of truth.
37. What is a CI/CD pipeline?
    A CI/CD pipeline is a series of steps that must be performed in order to deliver a new version of software.
38. What is the difference between continuous delivery and continuous deployment?
    Continuous delivery automates the release process up to production, while continuous deployment automatically deploys every change that passes all stages of the production pipeline.
39. What is DevSecOps?
    DevSecOps is an approach that integrates security practices within the DevOps process, promoting a “security as code” culture.
40. What is shift-left testing?
    Shift-left testing is an approach to software testing in which testing is performed earlier in the lifecycle.
41. What is a webhook?
    A webhook is a way for an app to provide other applications with real-time information by sending a HTTP POST request to a URL when certain events occur.
42. What is a reverse proxy?
    A reverse proxy is a server that sits in front of web servers and forwards client requests to those web servers.
43. What is a forward proxy?
    A forward proxy is a server that sits in front of a group of client machines and acts as an intermediary between the clients and the internet.
44. What is a stateless application?
    A stateless application is one that does not store any state information between requests.
45. What is a stateful application?
    A stateful application is one that saves client data from one session to the next.
46. What is a rolling update?
    A rolling update is a deployment strategy where an application is updated incrementally, replacing instances of the old version with new ones.
47. What is a sidecar pattern?
    The sidecar pattern is a design pattern where a separate container is deployed alongside the main application container to provide supporting features.
48. What is a service mesh?
    A service mesh is a dedicated infrastructure layer for handling service-to-service communication in microservices architectures.
49. What is Istio?
    Istio is an open-source service mesh that provides a uniform way to connect, manage, and secure microservices.
50. What is Helm?
    Helm is a package manager for Kubernetes that helps you define, install, and upgrade even the most complex Kubernetes applications.
51. What is a Helm chart?
    A Helm chart is a collection of files that describe a related set of Kubernetes resources.
52. What is GitLab?
    GitLab is a web-based DevOps lifecycle tool that provides a Git repository manager providing wiki, issue-tracking and CI/CD pipeline features.
53. What is Jira?
    Jira is a proprietary issue tracking product developed by Atlassian that allows bug tracking and agile project management.
54. What is a Kanban board?
    A Kanban board is a visual workflow management tool that helps visualize work, limit work-in-progress, and maximize efficiency.
55. What is technical debt?
    Technical debt refers to the implied cost of additional rework caused by choosing an easy solution now instead of using a better approach that would take longer.
56. What is a feature flag?
    A feature flag is a technique in software development that turns certain functionality on and off during runtime, without deploying new code.
57. What is A/B testing?
    A/B testing is a way to compare two versions of a single variable to determine which performs better in terms of a given metric.
58. What is blue-green deployment?
    Blue-green deployment is a technique for releasing applications by shifting traffic between two identical environments running different versions of the application.
59. What is canary release?
    A canary release is a technique to reduce the risk of introducing a new software version in production by slowly rolling out the change to a small subset of users before rolling it out to the entire infrastructure.
60. What is dark launching?
    Dark launching is a technique for releasing production-ready features to a subset of users prior to a full release.
61. What is a staging environment?
    A staging environment is a nearly exact replica of a production environment for software testing.
62. What is a sandbox environment?
    A sandbox environment is a testing environment that isolates untested code changes and outright experimentation from the production environment.
63. What is infrastructure drift?
    Infrastructure drift refers to the unplanned changes that occur in infrastructure configuration over time.
64. What is configuration drift?
    Configuration drift occurs when production or production-like environments begin to differ from the baseline configuration.
65. What is immutable infrastructure?
    Immutable infrastructure is an approach to managing services and software deployments where components are replaced rather than changed.
66. What is serverless computing?
    Serverless computing is a cloud computing execution model where the cloud provider dynamically manages the allocation and provisioning of servers.
67. What is AWS Lambda?
    AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers.
68. What is Azure Functions?
    Azure Functions is a serverless compute service that enables you to run code on-demand without having to explicitly provision or manage infrastructure.
69. What is Google Cloud Functions?
    Google Cloud Functions is a serverless execution environment for building and connecting cloud services.
70. What is a container registry?
    A container registry is a repository for storing and retrieving Docker container images.
71. What is Docker Compose?
    Docker Compose is a tool for defining and running multi-container Docker applications.
72. What is Docker Swarm?
    Docker Swarm is a native clustering and orchestration solution for Docker.
73. What is a Dockerfile?
    A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image.
74. What is a Docker image?
    A Docker image is a lightweight, standalone, executable package of software that includes everything needed to run an application.
75. What is a Docker container?
    A Docker container is a standardized unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.
76. What is container orchestration?
    Container orchestration automates the deployment, management, scaling, and networking of containers.
77. What is a Kubernetes cluster?
    A Kubernetes cluster is a set of node machines for running containerized applications.
78. What is a Kubernetes deployment?
    A Kubernetes Deployment is a Kubernetes object that provides declarative updates to applications.
79. What is a Kubernetes service?
    A Kubernetes Service is an abstract way to expose an application running on a set of Pods as a network service.
80. What is a Kubernetes namespace?
    A Kubernetes namespace provides a mechanism for isolating groups of resources within a single cluster.
81. What is a Kubernetes ConfigMap?
    A Kubernetes ConfigMap is an API object used to store non-confidential data in key-value pairs.
82. What is a Kubernetes Secret?
    A Kubernetes Secret is an object that contains a small amount of sensitive data such as a password, a token, or a key.
83. What is a Kubernetes DaemonSet?
    A DaemonSet ensures that all (or some) Nodes run a copy of a Pod.
84. What is a Kubernetes StatefulSet?
    A StatefulSet is the workload API object used to manage stateful applications.
85. What is a Kubernetes Ingress?
    An Ingress is an API object that manages external access to the services in a cluster, typically HTTP.
86. What is a Kubernetes PersistentVolume?
    A PersistentVolume (PV) is a piece of storage in the cluster that has been provisioned by an administrator or dynamically provisioned using Storage Classes.
87. What is a Kubernetes PersistentVolumeClaim?
    A PersistentVolumeClaim (PVC) is a request for storage by a user.
88. What is a Kubernetes StorageClass?
    A StorageClass provides a way for administrators to describe the “classes” of storage they offer.
89. What is a Kubernetes Operator?
    A Kubernetes Operator is a method of packaging, deploying and managing a Kubernetes application.
90. What is GitOps?
    GitOps is a way of implementing Continuous Deployment for cloud native applications.
91. What is ArgoCD?
    Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes.
92. What is Flux CD?
    Flux is a tool for keeping Kubernetes clusters in sync with sources of configuration (like Git repositories), and automating updates to configuration when there is new code to deploy.
93. What is a CI/CD pipeline?
    A CI/CD pipeline is a series of steps that must be performed in order to deliver a new version of software.
94. What is Jenkins X?
    Jenkins X is a CI/CD solution for modern cloud applications on Kubernetes.
95. What is Spinnaker?
    Spinnaker is an open-source, multi-cloud continuous delivery platform for releasing software changes with high velocity and confidence.
96. What is Terraform?
    Terraform is an open-source infrastructure as code software tool that enables defining and provisioning infrastructure using a declarative language.
97. What is Ansible?
    Ansible is an open-source software provisioning, configuration management, and application-deployment tool.
98. What is Puppet?
    Puppet is a software configuration management tool which includes its own declarative language to describe system configuration.
99. What is Chef?
    Chef is a configuration management tool written in Ruby and Erlang. It uses a pure-Ruby, domain-specific language (DSL) for writing system configuration “recipes”.
100. What is SaltStack?
     SaltStack is a Python-based, open-source configuration management software and remote execution engine.

Rajesh Kumar

I’m a DevOps/SRE/DevSecOps/Cloud Expert passionate about sharing knowledge and experiences. I am working at Cotocus. I blog tech insights at DevOps School, travel stories at Holiday Landmark, stock market tips at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at I reviewed , and SEO strategies at Wizbrand. 

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