DevOps interview questions

Containers vs virtual machines — key differences?

Easy · DevOps, Docker, Fresher

What is Docker and how does it work?

Easy · DevOps, Docker, Fresher

Docker image vs container — what is the difference?

Easy · DevOps, Docker, Fresher

Dockerfile best practices for production?

Medium · DevOps, Docker, Senior

How do Docker image layers affect build and deploy speed?

Medium · DevOps, Docker, Senior

What are multi-stage Docker builds and why use them?

Medium · DevOps, Docker, Senior

CMD vs ENTRYPOINT in Dockerfile?

Medium · DevOps, Docker, Senior

COPY vs ADD in Dockerfile?

Easy · DevOps, Docker, Fresher

Docker volumes vs bind mounts?

Medium · DevOps, Docker, Senior

What is Docker Compose and when do you use it?

Easy · DevOps, Docker, Fresher

Docker networking modes (bridge, host, overlay, none)?

Medium · DevOps, Docker, Senior

Essential docker run flags for backend developers?

Easy · DevOps, Docker, Fresher

Why use .dockerignore and what should it exclude?

Easy · DevOps, Docker, Fresher

Docker container lifecycle states?

Easy · DevOps, Docker, Fresher

What is the OCI spec and how does containerd fit in?

Medium · DevOps, Docker, Senior

Docker vs Podman — key differences?

Medium · DevOps, Docker, Senior

How do you set CPU and memory limits on containers?

Medium · DevOps, Docker, Senior

Container security best practices?

Hard · DevOps, Docker, Staff

What is a container registry and how does image tagging work?

Easy · DevOps, Docker, Fresher

How do you debug a running or failed container?

Medium · DevOps, Docker, Senior

What are distroless and minimal container images?

Medium · DevOps, Docker, Senior

Docker HEALTHCHECK vs Kubernetes probes?

Medium · DevOps, Docker, Senior

What is Docker build context and how do you optimize it?

Medium · DevOps, Docker, Senior

Why run containers as non-root and how do you configure it?

Medium · DevOps, Docker, Senior

Docker Swarm vs Kubernetes — when to use each?

Hard · DevOps, Docker, Staff

Explain Kubernetes architecture (control plane vs worker nodes).

Medium · DevOps, Kubernetes, Senior

What is a Pod and when would you run multiple containers in one Pod?

Easy · DevOps, Kubernetes, Fresher

Deployment vs StatefulSet vs DaemonSet?

Medium · DevOps, Kubernetes, Senior

Kubernetes Service types (ClusterIP, NodePort, LoadBalancer, Ingress)?

Medium · DevOps, Kubernetes, Senior

What is an Ingress and how does it differ from a Service?

Medium · DevOps, Kubernetes, Senior

ConfigMap vs Secret in Kubernetes?

Easy · DevOps, Kubernetes, Fresher

How does Horizontal Pod Autoscaler (HPA) work?

Medium · DevOps, Kubernetes, Senior

Liveness vs readiness vs startup probes?

Easy · DevOps, Kubernetes, Fresher

How do Kubernetes rolling updates work?

Medium · DevOps, Kubernetes, Senior

What is Helm and why use it?

Medium · DevOps, Kubernetes, Senior

What are Kubernetes namespaces and when do you use them?

Easy · DevOps, Kubernetes, Fresher

Labels and selectors in Kubernetes?

Easy · DevOps, Kubernetes, Fresher

Resource requests vs limits in Kubernetes?

Medium · DevOps, Kubernetes, Senior

PersistentVolume (PV) and PersistentVolumeClaim (PVC)?

Medium · DevOps, Kubernetes, Senior

How does RBAC work in Kubernetes?

Medium · DevOps, Kubernetes, Senior

What are Kubernetes NetworkPolicies?

Hard · DevOps, Kubernetes, Staff

Taints, tolerations, and node affinity?

Hard · DevOps, Kubernetes, Staff

What are init containers?

Medium · DevOps, Kubernetes, Senior

Explain the sidecar pattern in Kubernetes.

Medium · DevOps, Kubernetes, Senior

What is a PodDisruptionBudget (PDB)?

Medium · DevOps, Kubernetes, Staff

How does the Cluster Autoscaler work?

Medium · DevOps, Kubernetes, Staff

Jobs vs CronJobs in Kubernetes?

Easy · DevOps, Kubernetes, Fresher

Kustomize vs Helm — when to use each?

Medium · DevOps, Kubernetes, Senior

What is etcd and why is control plane HA important?

Hard · DevOps, Kubernetes, Architect

Essential kubectl commands for troubleshooting?

Medium · DevOps, Kubernetes, Senior

Explain Continuous Integration vs Continuous Delivery vs Continuous Deployment.

Easy · DevOps, CI/CD, Fresher

What stages should a production CI/CD pipeline include?

Medium · DevOps, CI/CD, Senior

Jenkins vs GitHub Actions — comparison?

Medium · DevOps, CI/CD, Senior

Why use an artefact repository (Nexus, Artifactory, ECR)?

Easy · DevOps, CI/CD, Fresher

How do you manage secrets in CI/CD pipelines?

Medium · DevOps, CI/CD, Senior

What are quality gates in a pipeline?

Medium · DevOps, CI/CD, Senior

How do you speed up CI builds with caching?

Easy · DevOps, CI/CD, Fresher

How does CI/CD support canary deployments?

Hard · DevOps, CI/CD, Staff

Git branching strategies for CI/CD (trunk-based, GitHub Flow, GitFlow)?

Medium · DevOps, CI/CD, Senior

What are Git hooks and how are they used in CI/CD?

Easy · DevOps, CI/CD, Fresher

What is pipeline-as-code and why does it matter?

Easy · DevOps, CI/CD, Fresher

GitHub Actions workflow anatomy — key concepts?

Medium · DevOps, CI/CD, Senior

Jenkins declarative pipeline — core structure?

Medium · DevOps, CI/CD, Senior

How does OIDC federation eliminate long-lived cloud credentials in CI?

Hard · DevOps, CI/CD, Architect

How do you promote artefacts across environments (dev → staging → prod)?

Medium · DevOps, CI/CD, Senior

Blue/green deployment — how does it work?

Medium · DevOps, CI/CD, Senior

Rolling deployment vs recreate strategy?

Easy · DevOps, CI/CD, Fresher

How do feature flags support CI/CD and trunk-based development?

Medium · DevOps, CI/CD, Senior

How do you handle database migrations in CI/CD?

Hard · DevOps, CI/CD, Architect

Rollback strategies when deployment fails?

Medium · DevOps, CI/CD, Staff

Semantic versioning (SemVer) in release management?

Easy · DevOps, CI/CD, Fresher

What checks should run on every pull request?

Medium · DevOps, CI/CD, Senior

How do you handle flaky tests in CI/CD?

Medium · DevOps, CI/CD, Senior

What are DORA metrics and why do they matter?

Medium · DevOps, CI/CD, Senior

What is GitOps and how does it relate to CI/CD?

Medium · DevOps, CI/CD, Senior

Maven vs Gradle — when to use each?

Easy · DevOps, Build, Config & Debug, Fresher

Explain the Maven build lifecycle phases.

Easy · DevOps, Build, Config & Debug, Fresher

How does dependency management work (Maven BOM, dependency convergence)?

Medium · DevOps, Build, Config & Debug, Senior

Multi-module Maven/Gradle project structure and build order?

Medium · DevOps, Build, Config & Debug, Senior

12-factor app: how should configuration be handled?

Easy · DevOps, Build, Config & Debug, Fresher

Externalized configuration patterns for microservices?

Medium · DevOps, Build, Config & Debug, Senior

Spring Boot profiles — how do they work?

Easy · DevOps, Build, Config & Debug, Fresher

Spring Boot property source precedence order?

Medium · DevOps, Build, Config & Debug, Senior

Environment variables vs configuration files — trade-offs?

Easy · DevOps, Build, Config & Debug, Fresher

Secrets vs configuration — how do you separate them?

Medium · DevOps, Build, Config & Debug, Senior

What is Spring Cloud Config Server?

Medium · DevOps, Build, Config & Debug, Senior

What is build reproducibility and why does it matter?

Medium · DevOps, Build, Config & Debug, Senior

How do you optimize CI builds in a monorepo?

Hard · DevOps, Build, Config & Debug, Architect

JVM tuning for production containers (heap, GC)?

Hard · DevOps, Build, Config & Debug, Staff

Structured logging and correlation IDs in distributed systems?

Medium · DevOps, Build, Config & Debug, Senior

Log levels and what to log in production?

Easy · DevOps, Build, Config & Debug, Fresher

How do you capture and analyse a thread dump?

Medium · DevOps, Build, Config & Debug, Senior

How do you debug OutOfMemoryError in production?

Hard · DevOps, Build, Config & Debug, Staff

Remote debugging — how to do it safely?

Medium · DevOps, Build, Config & Debug, Senior

Health check endpoints (Spring Boot Actuator)?

Easy · DevOps, Build, Config & Debug, Fresher

How do you debug applications running in containers/Kubernetes?

Medium · DevOps, Build, Config & Debug, Senior

Role of Makefiles and build scripts in DevOps?

Easy · DevOps, Build, Config & Debug, Fresher

Feature flags as a configuration concern?

Medium · DevOps, Build, Config & Debug, Senior

How do you manage configuration across dev, staging, and prod?

Medium · DevOps, Build, Config & Debug, Senior

Debugging distributed systems — tracing and observability?

Hard · DevOps, Build, Config & Debug, Architect

Essential Linux commands every DevOps engineer must know?

Easy · DevOps, Linux & Shell, Fresher

Explain Linux file permissions (rwx) and how they work?

Easy · DevOps, Linux & Shell, Fresher

How do you manage and troubleshoot Linux processes?

Easy · DevOps, Linux & Shell, Fresher

Bash scripting basics for DevOps automation?

Easy · DevOps, Linux & Shell, Fresher

How do you analyse logs on a Linux server during an incident?

Medium · DevOps, Linux & Shell, Senior

How do you troubleshoot 'disk full' errors in production?

Medium · DevOps, Linux & Shell, Senior

Cron jobs vs systemd timers — when to use each?

Medium · DevOps, Linux & Shell, Senior

SSH access management and hardening for servers?

Medium · DevOps, Linux & Shell, Senior

Linux performance tuning — CPU, memory, I/O?

Hard · DevOps, Linux & Shell, Staff

How do Linux namespaces and cgroups relate to containers?

Medium · DevOps, Linux & Shell, Senior

How do you create and manage systemd services?

Medium · DevOps, Linux & Shell, Senior

Inodes, hard links, and symbolic links — explain?

Medium · DevOps, Linux & Shell, Senior

Git fundamentals — staging, commits, remotes, and branches?

Easy · DevOps, Git & Version Control, Fresher

Common Git branching strategies for DevOps teams?

Easy · DevOps, Git & Version Control, Fresher

Git merge vs rebase — when to use each?

Easy · DevOps, Git & Version Control, Fresher

How do you resolve merge conflicts in a CI/CD workflow?

Medium · DevOps, Git & Version Control, Senior

Git hooks — pre-commit, pre-push, and CI integration?

Medium · DevOps, Git & Version Control, Senior

Signed commits and verified tags for supply chain security?

Medium · DevOps, Git & Version Control, Senior

Monorepo vs polyrepo — Git strategies for microservices?

Medium · DevOps, Git & Version Control, Senior

git bisect and cherry-pick for production incidents?

Hard · DevOps, Git & Version Control, Staff

IaaS vs PaaS vs SaaS — explain with DevOps examples?

Easy · DevOps, Cloud DevOps, Fresher

Cloud shared responsibility model for DevOps?

Easy · DevOps, Cloud DevOps, Fresher

AWS CI/CD services — CodePipeline, CodeBuild, CodeDeploy?

Medium · DevOps, Cloud DevOps, Senior

AWS ECS vs EKS — when to choose each for container workloads?

Medium · DevOps, Cloud DevOps, Senior

GCP Cloud Build and Artifact Registry for CI/CD?

Medium · DevOps, Cloud DevOps, Senior

Cloud IAM best practices for DevOps pipelines and operators?

Medium · DevOps, Cloud DevOps, Senior

Multi-account cloud strategy for enterprise DevOps?

Hard · DevOps, Cloud DevOps, Staff

Cloud disaster recovery — RPO, RTO, and backup strategies?

Hard · DevOps, Cloud DevOps, Staff

How does the AWS Well-Architected Framework apply to DevOps?

Hard · DevOps, Cloud DevOps, Architect

Azure DevOps Pipelines — key concepts?

Medium · DevOps, Cloud DevOps, Senior

CI/CD for serverless (Lambda, Cloud Functions)?

Medium · DevOps, Cloud DevOps, Senior

Managed Kubernetes — EKS, GKE, AKS operational differences?

Medium · DevOps, Cloud DevOps, Senior

Using S3/GCS for CI artefacts, static sites, and Terraform state?

Medium · DevOps, Cloud DevOps, Senior

Cloud autoscaling — horizontal vs vertical, predictive scaling?

Medium · DevOps, Cloud DevOps, Senior

AWS Secrets Manager vs Parameter Store vs GCP Secret Manager?

Medium · DevOps, Cloud DevOps, Senior

When to use Lambda vs containers vs EC2 for workloads?

Medium · DevOps, Cloud DevOps, Senior

What is Infrastructure as Code (IaC) and why use it?

Easy · DevOps, Infrastructure as Code, Fresher

Terraform core concepts — providers, resources, state?

Medium · DevOps, Infrastructure as Code, Senior

Terraform remote state and state locking — why critical?

Hard · DevOps, Infrastructure as Code, Staff

Terraform modules — structure and best practices?

Medium · DevOps, Infrastructure as Code, Senior

Ansible vs Terraform — when to use each?

Hard · DevOps, Infrastructure as Code, Staff

Terraform at scale — workspaces, stacks, and blast radius?

Hard · DevOps, Infrastructure as Code, Architect

AWS CloudFormation vs Terraform — comparison?

Medium · DevOps, Infrastructure as Code, Senior

Pulumi and AWS CDK — IaC with real programming languages?

Medium · DevOps, Infrastructure as Code, Senior

Ansible playbooks, roles, and inventory — explain?

Medium · DevOps, Infrastructure as Code, Senior

Immutable vs mutable infrastructure — DevOps perspective?

Medium · DevOps, Infrastructure as Code, Senior

Policy as code for infrastructure — OPA, Sentinel, Checkov?

Hard · DevOps, Infrastructure as Code, Staff

GitOps for infrastructure — repo structure and workflow?

Medium · DevOps, Infrastructure as Code, Senior

What is Site Reliability Engineering (SRE) and how does it differ from DevOps?

Easy · DevOps, SRE & Observability, Fresher

Metrics, logs, and traces — the three pillars of observability?

Easy · DevOps, SRE & Observability, Fresher

Explain SLI, SLO, and SLA with examples?

Medium · DevOps, SRE & Observability, Senior

How do you design SLOs for a production service?

Hard · DevOps, SRE & Observability, Staff

Error budgets — how do they balance reliability and velocity?

Hard · DevOps, SRE & Observability, Architect

Prometheus and Grafana — architecture and alerting?

Medium · DevOps, SRE & Observability, Senior

Incident response workflow for production outages?

Medium · DevOps, SRE & Observability, Senior

Blameless postmortems — structure and culture?

Hard · DevOps, SRE & Observability, Staff

Building sustainable on-call culture?

Hard · DevOps, SRE & Observability, Staff

Chaos engineering — principles and tools?

Hard · DevOps, SRE & Observability, Staff

Capacity planning for cloud-native systems?

Hard · DevOps, SRE & Observability, Staff

What is toil and how do SRE teams reduce it?

Medium · DevOps, SRE & Observability, Staff

OpenTelemetry — unified observability instrumentation?

Medium · DevOps, SRE & Observability, Senior

Incident command system (ICS) for large-scale outages?

Hard · DevOps, SRE & Observability, Architect

DORA metrics — what they measure and how to improve them?

Medium · DevOps, SRE & Observability, Senior

Centralized logging — ELK stack vs Loki vs cloud-native?

Medium · DevOps, SRE & Observability, Senior

How do you reduce alert fatigue across many services?

Medium · DevOps, SRE & Observability, Senior

Synthetic monitoring and health checks — blackbox vs whitebox?

Medium · DevOps, SRE & Observability, Senior

What is DevSecOps and how do you shift security left?

Medium · DevOps, Security & Compliance, Senior

Container image scanning and vulnerability management?

Medium · DevOps, Security & Compliance, Senior

HashiCorp Vault — dynamic secrets and rotation?

Hard · DevOps, Security & Compliance, Staff

Kubernetes security hardening checklist?

Hard · DevOps, Security & Compliance, Staff

Software supply chain security — SLSA, SBOM, signed artefacts?

Hard · DevOps, Security & Compliance, Architect

DevOps considerations for SOC 2 compliance?

Hard · DevOps, Security & Compliance, Staff

Zero trust principles for infrastructure access?

Medium · DevOps, Security & Compliance, Senior

Why must secrets never be committed to Git and how to prevent it?

Easy · DevOps, Security & Compliance, Fresher

WAF and DDoS protection in cloud deployments?

Medium · DevOps, Security & Compliance, Senior

Least privilege IAM and RBAC — practical implementation?

Medium · DevOps, Security & Compliance, Senior

PCI DSS and HIPAA basics for DevOps engineers?

Hard · DevOps, Security & Compliance, Staff

mTLS and service mesh for service-to-service security?

Hard · DevOps, Security & Compliance, Staff

HTTP vs HTTPS — how TLS works in production?

Easy · DevOps, Networking, Fresher

DNS fundamentals for DevOps — records, propagation, troubleshooting?

Easy · DevOps, Networking, Fresher

Load balancers — L4 vs L7, algorithms, health checks?

Medium · DevOps, Networking, Senior

VPC, subnets, and CIDR — cloud networking basics?

Medium · DevOps, Networking, Senior

NAT gateways, firewalls, and egress control?

Medium · DevOps, Networking, Senior

CDN and edge caching for global applications?

Medium · DevOps, Networking, Senior

Container and Kubernetes networking — how pods communicate?

Medium · DevOps, Networking, Senior

Service mesh networking — Istio traffic management?

Hard · DevOps, Networking, Staff

Global load balancing and multi-region traffic routing?

Hard · DevOps, Networking, Architect

Network troubleshooting methodology — "service unreachable"?

Medium · DevOps, Networking, Senior

GitOps with ArgoCD and Flux — how do they work?

Hard · DevOps, Platform & Architecture, Staff

Internal Developer Platform (IDP) — design principles?

Hard · DevOps, Platform & Architecture, Architect

Progressive delivery — canary, feature flags, and A/B at scale?

Hard · DevOps, Platform & Architecture, Staff

Improving DORA metrics organization-wide — Staff/Lead approach?

Hard · DevOps, Platform & Architecture, Staff

Multi-cloud strategy — when is it right vs over-engineering?

Hard · DevOps, Platform & Architecture, Architect

Cloud landing zone design for enterprise DevOps?

Hard · DevOps, Platform & Architecture, Architect

Cell-based architecture for blast radius reduction?

Hard · DevOps, Platform & Architecture, Architect

Leading a DevOps transformation in a traditional organization?

Hard · DevOps, Platform & Architecture, Architect

Build vs buy for DevOps tooling — decision framework?

Hard · DevOps, Platform & Architecture, Architect

Multi-region active-active architecture for DevOps teams?

Hard · DevOps, Platform & Architecture, Architect

Zero trust architecture for cloud-native platforms?

Hard · DevOps, Platform & Architecture, Architect

FinOps at scale — cloud cost governance for platform teams?

Hard · DevOps, Platform & Architecture, Architect