Basic DevOps questions
1. What is DevOps?
DevOps is a culture and set of practices that brings development and operations together to deliver software quickly and reliably through automation, CI/CD, infrastructure as code, monitoring and shared ownership.
2. Continuous integration vs delivery vs deployment?
Continuous integration merges code often and runs automated builds and tests. Continuous delivery keeps every change releasable with a manual approval to production. Continuous deployment releases every passing change automatically.
3. git merge vs git rebase?
Merge combines branches with a merge commit and keeps the history as it happened. Rebase replays your commits on top of another branch for a linear history; do not rebase commits that others have already pulled.
Intermediate DevOps questions
4. Docker image vs container?
An image is a read-only, layered template built from a Dockerfile. A container is a running instance of an image with its own writable layer, process space and network.
5. How do you make Docker images smaller and safer?
Use slim or distroless base images, multi-stage builds, combine and order layers for caching, add a .dockerignore, run as a non-root user, pin versions and scan images for vulnerabilities.
6. What are Pods, Deployments and Services in Kubernetes?
A Pod is the smallest unit and runs one or more containers. A Deployment manages replica Pods with rolling updates and rollbacks. A Service gives Pods a stable network endpoint and load balancing (ClusterIP, NodePort, LoadBalancer).
7. What is infrastructure as code?
Defining servers, networks and cloud resources in version-controlled files with tools such as Terraform or CloudFormation, so environments are reproducible, reviewed like code and created automatically.
Advanced DevOps questions
8. Blue-green vs canary deployment?
Blue-green runs two identical environments and switches traffic all at once, allowing instant rollback. Canary releases the new version to a small percentage of users first and increases traffic while monitoring errors.
9. How do you monitor production systems?
Collect metrics (Prometheus, CloudWatch), logs (ELK, Loki) and traces (OpenTelemetry), build dashboards in Grafana, and alert on SLOs such as error rate, latency and saturation instead of on every metric.
10. How do you manage secrets in pipelines?
Never commit secrets. Store them in a vault or the CI's secret store (HashiCorp Vault, AWS Secrets Manager, GitHub Actions secrets), inject them at runtime as environment variables, rotate them and give each pipeline least-privilege access.
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