Reducing final image size by 80 percent in Docker - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the Dockerfile line to use a smaller base image.

Docker

FROM [1]

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Aalpine:latest

Bubuntu:latest

Cdebian:latest

Dcentos:latest

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a full Linux distribution like Ubuntu increases image size.

Using CentOS or Debian also results in larger images.

Using alpine:latest as the base image reduces the image size significantly because Alpine is a minimal Linux distribution.

2fill in blank

medium

Complete the command to remove unnecessary package cache after installation.

Docker

RUN apk add --no-cache curl && rm -rf [1]

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A/tmp

B/usr/local/bin

C/var/cache/apk/*

D/etc/apk

Attempts:

3 left

💡 Hint

Common Mistakes

Removing /usr/local/bin deletes installed binaries.

Removing /etc/apk breaks package management.

Removing /tmp may not affect package cache.

Removing /var/cache/apk/* clears the package cache, reducing image size.

3fill in blank

hard

Fix the error in the Dockerfile line to reduce layers by combining commands.

Docker

RUN apk add curl \
    && [1] /var/cache/apk/*

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Acp -r

Bmkdir

Ctouch

Drm -rf

Attempts:

3 left

💡 Hint

Common Mistakes

Using mkdir or cp does not remove files.

touch only creates empty files.

Using rm -rf removes the cache in the same layer, reducing final image size.

4fill in blank

hard

Fill both blanks to create a multi-stage Dockerfile that copies only the final binary.

Docker

FROM golang:1.20-alpine AS builder
WORKDIR /app
COPY . .
RUN go build -o [1] .

FROM alpine:latest
COPY --from=builder /app/[2] /usr/local/bin/
CMD ["[3]"]

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Aapp

Bmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the binary causes copy errors.

CMD not matching the binary name causes runtime errors.

The binary is named main in the build step and copied from the builder stage. The command runs main.

5fill in blank

hard

Fill all three blanks to create a Dockerfile that cleans up build tools and reduces image size.

Docker

FROM node:18-alpine AS build
WORKDIR /app
COPY package.json .
RUN npm install
COPY . .
RUN npm run build

FROM alpine:latest
RUN apk add --no-cache [1]
COPY --from=build /app/dist /app
CMD ["[2]", "[3]"]

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

Anodejs

Bnpm

Cnode

Dserve

Eindex.js

Attempts:

3 left

💡 Hint

Common Mistakes

Installing npm in the final image increases size unnecessarily.

CMD not matching the app entry point causes failure.

The final image installs only node to run the app. The CMD runs serve index.js to start the app.