Development container patterns in Docker - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the Dockerfile line to set the base image for a development container.

Docker

FROM [1]

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

Apython:3.12-slim

Bnode:18-alpine

Cubuntu:latest

Dnginx:stable

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a production-only image like nginx for development.

The FROM instruction sets the base image. Here, node:18-alpine is a lightweight Node.js image suitable for development.

2fill in blank

medium

Complete the Dockerfile command to copy local source code into the container.

Docker

COPY [1] /app

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A./

B./src

C/src

Dsrc/

Attempts:

3 left

💡 Hint

Common Mistakes

Using absolute paths like /src which don't exist in the build context.

The COPY ./ /app command copies all files from the current directory into the container's /app folder.

3fill in blank

hard

Fix the error in the Dockerfile command to install dependencies using npm.

Docker

RUN npm [1]

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Ainstall

Bupdate

Cupgrade

Dbuild

Attempts:

3 left

💡 Hint

Common Mistakes

Using npm update which updates packages but does not install new ones.

The correct command to install dependencies is npm install. Other options do not install packages.

4fill in blank

hard

Fill both blanks to expose port 3000 and set the default command to start the app.

Docker

EXPOSE [1]
CMD ["npm", "[2]"]

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A3000

Bstart

Cbuild

D8080

Attempts:

3 left

💡 Hint

Common Mistakes

Exposing the wrong port or using npm build which only compiles code.

Port 3000 is commonly used for development servers. The command npm start runs the start script defined in package.json.

5fill in blank

hard

Fill all three blanks to create a volume mount for live code editing and set environment variable for development mode.

Docker

VOLUME ["[1]"]
ENV NODE_ENV=[2]
CMD ["npm", "[3]"]

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

A/app

Bdevelopment

Cstart

D/src

Attempts:

3 left

💡 Hint

Common Mistakes

Mounting the wrong directory or forgetting to set NODE_ENV for development.

Mounting /app allows live code changes inside the container. Setting NODE_ENV=development enables dev mode. Running npm start launches the app.