Docker Compose for dev environment - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the version of Docker Compose file format.

Docker

version: '[1]'
services:
  app:
    image: myapp:latest

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

A4

B3.8

C1

D2.0

Attempts:

3 left

💡 Hint

Common Mistakes

Using a numeric value without quotes causes syntax errors.

Choosing an unsupported version number.

The version '3.8' is a widely used and stable Docker Compose file format version suitable for development environments.

2fill in blank

medium

Complete the code to expose port 8000 on the host machine.

Docker

services:
  web:
    image: mywebapp
    ports:
      - '[1]:8000'

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

A443

B80

C8080

D8000

Attempts:

3 left

💡 Hint

Common Mistakes

Using a port number already in use on the host.

Swapping host and container ports.

Mapping port 8000 on the host to port 8000 in the container allows access to the app on localhost:8000.

3fill in blank

hard

Fix the error in the volume mount to map the current directory to /app inside the container.

Docker

services:
  backend:
    image: backend:dev
    volumes:
      - '[1]:/app'

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

A./

B/app

C.

D./src

Attempts:

3 left

💡 Hint

Common Mistakes

Using absolute paths that don't exist on the host.

Using incorrect relative paths like '.' without slash.

Using './' correctly maps the current directory to /app in the container, which is common in dev setups.

4fill in blank

hard

Fill both blanks to set environment variables for the service.

Docker

services:
  db:
    image: postgres
    environment:
      - [1]=devuser
      - [2]=devpass

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

APOSTGRES_USER

BPOSTGRES_PASSWORD

CDB_USER

DDB_PASS

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic variable names that Postgres does not recognize.

Swapping user and password variable names.

Postgres expects environment variables POSTGRES_USER and POSTGRES_PASSWORD to set up the database user and password.

5fill in blank

hard

Fill all three blanks to define a service with build context, restart policy, and command override.

Docker

services:
  api:
    build: [1]
    restart: [2]
    command: [3]

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

A./api

Balways

C"python app.py"

Dnever

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect paths for build context.

Choosing wrong restart policies like 'never' for dev environments.

Not quoting the command string properly.

The build context './api' points to the Dockerfile location. Restart policy 'always' keeps the container running. The command overrides the default to run the app.