Cache mount for faster builds in Docker - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a cache mount in Docker builds?

A cache mount is a way to save and reuse files or data between Docker build steps to speed up the build process by avoiding repeated work.

beginner

How does using a cache mount improve Docker build speed?

It stores intermediate files or dependencies so Docker can reuse them in later builds instead of downloading or compiling again.

intermediate

Which Dockerfile syntax enables cache mounts?

The syntax is: RUN --mount=type=cache,target=/path/to/cache <command>. This tells Docker to use a cache at the specified path during the RUN step.

intermediate

What is the purpose of the 'target' option in a cache mount?

The 'target' option specifies the directory inside the container where the cache will be stored and reused during the build.

intermediate

Can cache mounts be shared across different builds?

Yes, cache mounts can be reused across builds if the cache is stored persistently, which helps speed up builds on the same machine or CI environment.

What does the cache mount do in a Docker build?

A Saves and reuses files between build steps to speed up builds

B Deletes all files after each build step

C Runs the build in a separate container

D Uploads the build to Docker Hub automatically

Cache mounts save files between steps so Docker can reuse them, making builds faster.

Which Dockerfile command syntax uses cache mounts?

A RUN --mount=type=cache,target=/cache <command>

B COPY --cache /cache <command>

C FROM --cache=enabled

D CMD --cache /cache

The RUN command with --mount=type=cache,target=... enables cache mounts during build steps.

What is the role of the 'target' in a cache mount?

A It specifies the base image for the build

B It names the cache for Docker Hub

C It sets the directory inside the container to store cached data

D It defines the network for the build

The 'target' option tells Docker where inside the container to save and reuse cached files.

Can cache mounts help when building the same Docker image multiple times?

A Only if the build uses multiple stages

B No, cache mounts are cleared after each build

C Only if the image is pushed to a registry

D Yes, they speed up repeated builds by reusing cached data

Cache mounts keep data between builds, so repeated builds run faster.

Which of these is NOT a benefit of using cache mounts?

A Faster builds by reusing data

B Automatic image deployment

C Less CPU usage during repeated builds

D Reduced network downloads during build

Cache mounts speed up builds but do not handle image deployment.

Explain how cache mounts work in Docker builds and why they help speed up the process.

Think about how saving work done once can save time later.

Describe the syntax to use a cache mount in a Dockerfile and what each part means.

Look at how the RUN command is extended with --mount.