Interview prep · 3 parts

Docker Interview Questions

Images and containers, Dockerfiles, layers, volumes, networking and Compose. Each question has an answer you can say out loud, the reasoning, and the follow-ups to expect.

Also coverscontainersDockerfileDocker Composecontainerization

Start with part 1 →All topics
In this series
1
parts published
6
questions
2
parts coming
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3 Beginner2 Intermediate1 Advanced
About this series

What Docker interviews test

Docker questions come up in backend, DevOps and full-stack interviews alike. Interviewers want to know whether you understand what an image and a container really are, how a Dockerfile builds layers, how data survives a container being replaced, and how to keep images small and secure.

Each answer here starts with the version you can say in one breath, then explains why, with real Dockerfile and command-line examples, the common mistake, and the follow-ups to expect.

Follow the order, or jump in

The 3 parts

PART 016 questionsDocker Interview Questions and AnswersImages and containers, Dockerfile instructions, volumes and smaller images - the Docker questions that come up most, with short answers and real examples.3 Beginner2 Intermediate1 Advanced12 min
PART 02Coming soonDocker Networking and Compose
PART 03Coming soonDocker in Production: Security and Debugging
Jump to an answer

6 Docker questions in this series

Docker Interview Questions and Answers

  1. What is the difference between an image and a container?Beginner
  2. How is a container different from a virtual machine?Beginner
  3. What is the difference between CMD and ENTRYPOINT?Intermediate
  4. What is the difference between COPY and ADD?Beginner
  5. What is the difference between a volume and a bind mount?Intermediate
  6. How do you make a Docker image smaller?Advanced
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How to use this series
  1. Turn on Practice mode and answer each question out loud.
  2. Reveal the answer and compare it with the short version.
  3. Learn the follow-ups - that is where interviews are decided.
  4. Come back the night before and skim the short answers.