Top 40 Docker Interview Questions
Preparing for a DevOps interview? Docker questions
are asked in almost every interview.
Beginner Questions
Q: What is Docker?
Docker is a containerization platform that packages
applications with dependencies into portable containers.
Q: Difference between image and container?
Image: read-only blueprint (like a class)
Container: running instance of image (like an object)
Q: What is Dockerfile?
Text file with instructions to build a Docker image.
FROM, WORKDIR, COPY, RUN, CMD, EXPOSE
Intermediate Questions
Q: What is multi-stage build?
Uses multiple FROM statements. Build in full image,
copy only artifacts to minimal runtime image.
Result: 1.2GB β 80MB production image!
Q: CMD vs ENTRYPOINT?
ENTRYPOINT: always runs, not easily overridden
CMD: default args, easily overridden at runtime
Advanced Questions
Q: How do namespaces enable containers?
pid, net, mnt, uts, ipc, user namespaces
provide isolation at OS level without VM overhead.
...and 35 more questions with answers π
π Full Q&A + PDF: devopsrise.vercel.app/qa
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