Why multi-stage builds reduce image size in Docker - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a multi-stage build with the first stage named 'builder'.

Docker

FROM alpine AS [1]

Drag options to blanks, or click blank then click option'

Abase

Bfinal

Cbuilder

Dstage1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'final' or 'base' as the first stage name, which is usually reserved for the last stage.

The first stage is named 'builder' to separate build dependencies from the final image.

2fill in blank

medium

Complete the code to copy the built binary from the 'builder' stage to the final stage.

Docker

COPY --from=[1] /app/myapp /usr/local/bin/myapp

Drag options to blanks, or click blank then click option'

Astage1

Bfinal

Cbase

Dbuilder

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'final' or 'base' instead of the build stage name.

The --from=builder option copies files from the 'builder' stage.

3fill in blank

hard

Fix the error in the Dockerfile line that copies files from the build stage.

Docker

COPY --from=[1] /app/myapp /usr/local/bin/myapp

Drag options to blanks, or click blank then click option'

Abuild

Bbuilder

Cbuild-stage

Dbuilder-stage

Attempts:

3 left

💡 Hint

Common Mistakes

Using similar but incorrect names like 'build' or 'builder-stage'.

The stage name must exactly match the name given in the FROM ... AS line, which is 'builder'.

4fill in blank

hard

Fill both blanks to create a final stage that uses a small base image and copies the binary from the builder.

Docker

FROM [1]
COPY --from=[2] /app/myapp /usr/local/bin/myapp

Drag options to blanks, or click blank then click option'

Aalpine

Bbuilder

Cubuntu

Dfinal

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ubuntu' which is larger, or wrong stage names.

The final stage uses 'alpine' for a small image and copies from the 'builder' stage.

5fill in blank

hard

Fill all three blanks to complete a multi-stage Dockerfile that builds and copies a binary, then sets the entrypoint.

Docker

FROM golang:1.20 AS [1]
WORKDIR /app
COPY . .
RUN go build -o myapp .
FROM [2]
COPY --from=[3] /app/myapp /usr/local/bin/myapp
ENTRYPOINT ["myapp"]

Drag options to blanks, or click blank then click option'

Abuilder

Balpine

Dubuntu

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent stage names or large base images.

The first stage is named 'builder'. The final stage uses 'alpine'. The copy command uses '--from=builder'.