Top 5 Essential Docker Interview Questions & Answers | Part 2: Junior to Pro

Are you preparing for a DevOps, Backend, or Software Engineering interview? Welcome to Part 2 of our Docker Interview Series: Images & Builds! In this interactive video, we test your knowledge with 5 of the most-asked Docker image and Dockerfile interview questions, scaling from beginner-friendly warm-ups to genuinely hard, senior-level concepts. Here is how it works: I will present a question, you pause the video and try to answer it out loud, and then I will reveal the expert-level answer! 📌 What we cover in this episode: • Q1 (Very Easy): What a Dockerfile actually is — the recipe of instructions that builds an image. • Q2 (Easy): What an image layer is, and why each instruction becomes a cached, shareable layer. • Q3 (Medium): COPY vs ADD — which one to use, and the one case where ADD is actually the right call. • Q4 (Hard): Multi-stage builds — building in a heavy stage but shipping only the final artifact. • Q5 (Very Hard): How to build a minimal, secure production image — small base, multi-stage, non-root, and no secrets baked into layers. Whether you are a junior developer just getting into containerization or a seasoned Docker engineer tightening up your build pipelines, this test will show you exactly where you stand. 👇 Drop your score (out of 5) in the comments below! Be honest—did you make it past the checkpoint? Let me know which concept you'd like a dedicated deep-dive video on. 🔔 Don't forget to SUBSCRIBE to learn Docker the easy way and get notified when "Part 3 — Data & Networking" drops!