Docker Compose | Declarative Multi-Service Stacks

You will describe a web + database + cache stack in a single Compose file and launch it with one command. By the end you will have reproducible, ordered startup with health checks instead of fragile manual docker run sequences.

Learning Objectives

Define services, networks, and volumes declaratively.
Order startup with depends_on and healthchecks.
Manage the stack lifecycle with compose commands.
Time: ~3 hours · Difficulty: Intermediate · Prereqs: Docker Compose v2.

Architecture Overview

graph LR C[compose.yaml] -->|docker compose up| Stack subgraph Stack Web[web] --> DB[(db)] Web --> Cache[(redis)] end

Environment Setup

You will need: Docker Compose v2 (docker compose version).

Before you begin: create a project directory for the compose file.

Step-by-Step Execution

Write the compose file

Declaring services with a healthcheck and depends_on guarantees the DB is ready before the web app starts.

# compose.yaml
services:
  db:
    image: postgres:16
    environment: { POSTGRES_PASSWORD: secret }
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 5s
  web:
    image: nginx:stable
    depends_on:
      db: { condition: service_healthy }
    ports: ["8080:80"]

Bring the stack up

docker compose up -d

Creates the network, volumes, and starts services in dependency order.

Check status and logs

$ docker compose ps

NAME SERVICE STATUS PORTS proj-db db Up (healthy) proj-web web Up 0.0.0.0:8080->80/tcp

Progress So Far

graph LR A[01 Write compose] -->|done| B[02 up -d] B -->|done| C[03 ps + logs] style A fill:#1a4a1a,stroke:#00ff00,color:#fff style B fill:#1a4a1a,stroke:#00ff00,color:#fff style C fill:#1a4a1a,stroke:#00ff00,color:#fff

Testing & Validation

curl -s -o /dev/null -w "%{http_code}\n" http://localhost:8080 && docker compose down

You should see 200, then a clean teardown. If so, your whole stack is reproducible from one file.

Troubleshooting

web starts before db is ready: use a healthcheck with condition: service_healthy.
Old containers conflict: run docker compose down before re-creating.
Env not applied: confirm a .env file or environment keys are present.

Extension Ideas

Split prod/dev with compose override files.
Promote the stack to Kubernetes in Multi-Container Applications.
Add the build + deploy to CI/CD.

Key Results

Launched a 3-service stack with a single command.
Guaranteed startup order with healthchecks and depends_on.
Made the environment reproducible from one declarative file.
Verified the app and a clean teardown.

Docker Compose: Bring Up a Full Stack with One Command