Docker Compose for local development in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

Microservices

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

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

Alatest

B3.8

Cv2

D1.0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'latest' as version causes errors.

Using 'v2' is not a valid version string here.

The version field in Docker Compose specifies the file format version. '3.8' is a commonly used stable version for modern Docker Compose files.

2fill in blank

medium

Complete the code to define a service named 'db' using the official PostgreSQL image.

Microservices

services:
  db:
    image: [1]

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

Aredis:6

Bmysql:latest

Cpostgres:13

Dmongo:4.4

Attempts:

3 left

💡 Hint

Common Mistakes

Using MySQL or MongoDB images for a PostgreSQL service.

Omitting the version tag may cause unexpected updates.

The db service uses the official PostgreSQL image tagged 'postgres:13' for version 13.

3fill in blank

hard

Fix the error in the environment variable syntax for the 'web' service.

Microservices

services:
  web:
    image: myapp:latest
    environment:
      - DATABASE_URL=[1]

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

A"postgres://user:pass@db:5432/mydb"

Bpostgres://user:pass@db:5432/mydb

C'postgres://user:pass@db:5432/mydb'

DDATABASE_URL=postgres://user:pass@db:5432/mydb

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the URL causes YAML parsing errors.

Using single quotes may work but double quotes are safer here.

Environment variable values with special characters should be quoted with double quotes in YAML to avoid parsing errors.

4fill in blank

hard

Fill both blanks to correctly map the local port 8080 to the container port 80 and mount the current directory to /app inside the container.

Microservices

services:
  web:
    ports:
      - '[1]:[2]'
    volumes:
      - './:[3]'

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

A8080

B80

C/app

D/var/www

Attempts:

3 left

💡 Hint

Common Mistakes

Reversing port mapping order.

Mounting to wrong container directory.

Port mapping uses 'host_port:container_port' format, so '8080:80' maps local 8080 to container 80. Volume mounts map local './' to container '/app' to share code.

5fill in blank

hard

Fill all three blanks to define a 'depends_on' relationship where 'web' depends on 'db', and set restart policy to always.

Microservices

services:
  web:
    depends_on:
      - [1]
    restart: [2]
  db:
    image: postgres:13
    restart: [3]

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

Adb

Balways

Cno

Dnever

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong service name in depends_on.

Setting restart policy to 'no' disables auto-restart.

The 'web' service depends on 'db' to start first. Setting 'restart: always' ensures services restart automatically on failure.