Installing docker compose

Docker Compose is a tool used for defining and managing multi-container Docker applications. With Docker Compose, you can configure and run applications consisting of multiple interconnected services (like web servers, databases, caches, etc.) using a single YAML file (docker-compose.yml). This simplifies the process of orchestrating complex applications by allowing you to define and manage all services together, instead of managing each container individually.

<em># Download docker-compose dan store in /usr/local/bin/docker-compose</em>

curl -SL https://github.com/docker/compose/releases/download/v2.29.3/docker-compose-linux-x86_64 -o /usr/local/bin/docker-compose
 
<em># act as executable file</em>
sudo chmod +x /usr/local/bin/docker-compose

Key Concepts in Docker Compose

1. Service: A service represents a container configuration. Each service in Docker Compose is typically an individual container that is part of your application stack, such as a web server, a database, or a cache.
2. Network: Docker Compose automatically creates a network for the services defined in the Compose file, allowing them to communicate with each other by their service names.
3. Volume: Volumes in Docker Compose are used to persist data across container restarts, useful for storing data that should remain even if the containers are removed.

Benefits of Docker Compose

• Easier Configuration: You define the entire multi-container setup in one file, making it easy to share, version control, and replicate.
• Environment Management: Compose makes it easy to define different environments (e.g., production, staging, development) by using different docker-compose.yml files or using environment variables.
• Simplified Deployment: You can start all services with a single command, which simplifies launching complex applications.
• Scalability: You can scale services up or down by adjusting the number of container instances.

Example docker-compose.yml

Here’s an example of a docker-compose.yml file that sets up a simple web application with a web server (using Nginx) and a database (using MySQL):

version: '3'
services:
  web:
    image: nginx:latest
    ports:
      - "80:80"
    volumes:
      - ./web:/usr/share/nginx/html
    networks:
      - app-network

  db:
    image: mysql:5.7
    environment:
      MYSQL_ROOT_PASSWORD: example
      MYSQL_DATABASE: mydb
    volumes:
      - db-data:/var/lib/mysql
    networks:
      - app-network

networks:
  app-network:

volumes:
  db-data:

How to Use Docker Compose

1. Start Services: Run the following command in the same directory as your docker-compose.yml file:

   docker-compose up

This will build and start all containers specified in the file.

2. Run in Detached Mode: To run the services in the background, add the -d flag:

   docker-compose up -d

3. Stop Services:

   docker-compose down

This stops and removes all containers, networks, and volumes created by up.

4. Scaling: You can scale services by specifying the --scale flag:

   docker-compose up -d --scale web=3

Docker Compose is widely used in development and testing environments and is also commonly used in staging and production setups for smaller applications. It’s a powerful tool for building and managing multi-container applications efficiently.