# Getting Started with Docker Compose
Today I learned how to use Docker Compose to simplify the development and deployment of multi-container applications.
## The Problem with Multiple Containers
Before using Docker Compose, I was managing multiple containers manually with individual docker run commands. This approach had several drawbacks:
- Complex startup scripts with many command-line arguments
- No easy way to define container dependencies and startup order
- Difficulty sharing configurations across team members
- Tedious network configuration to enable container communication
## Docker Compose Solution
Docker Compose solves these problems by allowing you to define your entire application stack in a single YAML file (docker-compose.yml).
## Key Concepts I Learned
- **Services**: Definitions for each container in your application
- **Networks**: How containers communicate with each other
- **Volumes**: Persistent data storage that survives container restarts
- **Environment Variables**: Configuration that can change between environments
- **Dependencies**: Controlling the order in which containers start
## My First Compose File
I created a simple web application with a frontend, backend API, and database. The compose file defined all three services, their connections, and configuration.
## Benefits Realized
- **Simplified Development**: One command (docker-compose up) to start the entire stack
- **Consistent Environments**: Everyone on the team uses the exact same configuration
- **Easy Onboarding**: New developers can get started without complex setup instructions
- **Version Control**: Infrastructure configuration stored alongside application code
This approach has significantly streamlined our development workflow and reduced environment-related issues.
Code Example
version: '3.8'
services:
frontend:
build: ./frontend
ports:
- "3000:3000"
depends_on:
- backend
environment:
- API_URL=http://backend:8000
backend:
build: ./backend
ports:
- "8000:8000"
depends_on:
- database
environment:
- DB_HOST=database
- DB_USER=postgres
- DB_PASSWORD=example
- DB_NAME=myapp
database:
image: postgres:13
volumes:
- db-data:/var/lib/postgresql/data
environment:
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=example
- POSTGRES_DB=myapp
volumes:
db-data:DockerDocker ComposeContainers