Squashing layers in Docker - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does 'squashing layers' mean in Docker?

Squashing layers means combining multiple image layers into one to reduce image size and improve efficiency.

beginner

Why is squashing layers useful in Docker images?

It reduces the final image size, speeds up downloads, and makes the image easier to manage.

intermediate

Which Docker command option allows squashing layers during build?

The option is --squash used with docker build to combine layers.

intermediate

Does squashing layers affect Docker cache usage?

Yes, squashing can reduce cache efficiency because it merges layers, making incremental builds less effective.

intermediate

How can you enable squashing layers in Docker BuildKit?

Set the environment variable DOCKER_BUILDKIT=1 and use --squash with docker build.

What is the main benefit of squashing layers in Docker images?

A Smaller image size

B Faster container startup

C More layers created

D Improved network speed

Squashing layers reduces the image size by combining multiple layers into one.

Which Docker build option enables layer squashing?

A --flatten

B --compress

C --squash

D --merge

The --squash option is used to squash layers during a Docker build.

What is a downside of squashing layers in Docker builds?

A Reduced cache efficiency

B Slower build times

C Increased image size

D More complex Dockerfiles

Squashing reduces cache efficiency because it merges layers, making incremental builds less effective.

To use squashing with Docker BuildKit, what must you do?

A Use --compress flag only

B Set DOCKER_BUILDKIT=1 and use --squash

C Enable experimental Docker mode

D No special setup needed

You must enable BuildKit with DOCKER_BUILDKIT=1 and add --squash to the build command.

Which of these is NOT true about squashing layers?

A It merges multiple layers into one

B It may reduce build cache effectiveness

C It can reduce image size

D It always speeds up container startup

Squashing layers reduces image size but does not necessarily speed up container startup.

Explain what squashing layers means in Docker and why it might be useful.

Think about how combining layers affects image size and build process.

Describe how to enable squashing layers when building a Docker image using BuildKit.

Remember the environment variable and the build command option.