Quiz

Test your understanding of the concepts covered in the Modern Docker & Best Practices chapter.

Q1. What is the primary technical benefit of multi-stage builds in a Dockerfile?

A They allow compiling code in early stages with full SDKs and copying only built artifacts into a minimal runtime image, reducing image size and attack surface B They automatically run unit tests inside web browsers C They allow running multiple web servers on the same port D They replace Docker Compose files

Explanation

Multi-stage builds separate build-time dependencies (compilers, devDependencies) from runtime requirements, yielding significantly smaller, more secure images.

Q2. Why can building a Docker image on an Apple Silicon Mac (M1/M2/M3/M4) without specifying a platform cause an `exec format error` when deployed to a standard AWS EC2 server?

A Because Macs build ARM64 architecture binaries, whereas standard cloud EC2 servers run on AMD64/x86_64 CPU architecture B Because macOS uses Windows executable files by default C Because AWS EC2 does not support Linux containers D Because Docker Hub only allows images smaller than 1 MB

Explanation

Apple Silicon Macs use ARM64 CPUs, whereas standard cloud servers use AMD64/x86_64. Using `docker buildx build --platform linux/amd64` ensures cross-building for cloud x86 hosts.

Q3. What feature introduced in Docker Compose V2 automatically monitors source code edits and intelligently syncs files or rebuilds services in real time?

A Compose Watch (`docker compose up --watch`) B Compose Sync (`docker compose sync`) C Docker Live Reload D Container Hot Swap

Explanation

`docker compose watch` monitors project files and automatically syncs code changes into running containers or rebuilds services when dependency manifests change.

Q4. Why is running containers under a non-root user account (`USER appuser` in Dockerfile) a critical security best practice?

A It prevents attackers from gaining root access to the host operating system if an application vulnerability is exploited inside the container B Non-root containers run 50% faster than root containers C Docker Hub rejects all images that execute as root D Root users cannot read environment variables

Explanation

Running as non-root limits the blast radius of potential container escape exploits, ensuring an attacker cannot obtain root privileges on the underlying host.

Q5. Which built-in Docker CLI tool allows developers to scan Docker images for security vulnerabilities (CVEs) and base image update recommendations?

A docker scout B docker audit C docker scan-all D docker guard

Explanation

`docker scout` (e.g. `docker scout quickview` or `docker scout cves`) analyzes image layers and reports known vulnerabilities and patch recommendations.

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