Docker Compose — Commands — Practice Exercises

1 minute read

Practice the essential Docker Compose commands.

Exercise 1: Full Lifecycle

Start a stack, verify it’s running, view logs, then tear it down completely.

Solution 
services:
  web:
    image: nginx:alpine
    ports:
      - "80:80"

docker compose up -d           # Start
docker compose ps              # Verify running
docker compose logs web        # View logs
docker compose down            # Tear down
docker compose ps -a           # Verify removed

Exercise 2: Debug a Service

Shell into a running container, check its environment, and test DNS.

Solution 
docker compose up -d
docker compose exec web sh
# Inside container:
env                            # View environment
ping api                       # Test DNS (if api exists)
cat /etc/nginx/nginx.conf      # View config
exit

Exercise 3: Build and Rebuild

Build a service, make a change, then rebuild without cache.

Solution 
docker compose build api              # Initial build
# Make code changes...
docker compose build --no-cache api   # Force full rebuild
docker compose up -d                  # Start with new image

Exercise 4: Config Validation

Introduce an error in your compose file and use config to find it.

Solution 
# Add a typo to compose.yml, then:
docker compose config -q
# Shows: yaml: line X: ...

# Fix the error, then:
docker compose config -q
# No output = valid!

Exercise 5: File Copy

Copy a config file into a running container and verify it.

Solution 
echo "test config" > test.conf
docker compose up -d
docker compose cp test.conf web:/etc/nginx/test.conf
docker compose exec web cat /etc/nginx/test.conf

Output: test config

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