Lab: Docker Compose basics

Run two containers from public images with one compose.yaml. No Dockerfile, no application code. The goal is to see how Compose starts a stack, maps ports, and names services on the same network.

Lab objective

• Use docker compose up and down.
• Reach each service from your host with curl.
• Run docker compose ps and docker compose logs.

Prerequisites

• Docker with Compose v2 (docker compose).

Hands on

1. Project directory

mkdir -p peachycloudsecurity-compose-lab && cd peachycloudsecurity-compose-lab

2. Compose file

cat <<'EOF' > compose.yaml
services:
  web:
    image: nginx:1.27-alpine
    ports:
      - "8080:80"
  whoami:
    image: traefik/whoami:v1.10.2
    ports:
      - "8081:80"
EOF

web serves the default nginx page. whoami returns a short text response (container hostname and request headers) on port 80 inside the container, mapped to 8081 on your host.

3. Start the stack

docker compose up -d
docker compose ps

4. Call both services

curl -sS http://127.0.0.1:8080/ | head -n 3
curl -sS http://127.0.0.1:8081/ | head -n 5

5. Logs and stop

docker compose logs --tail=10 web
docker compose logs --tail=10 whoami
docker compose down

Clean up

cd .. && rm -rf peachycloudsecurity-compose-lab

Summary

• Compose pulled two images and wired a private network between services (you can add more later).
• ports publishes containers to your laptop; service names such as web are DNS names inside the Compose network.
• The same multi-service idea appears on larger platforms that schedule containers for you.

• Next step: Image Build and Delivery, then Theory: Registry and image lifecycle and Lab: Slim Python images.