Docker Compose is a tool for defining and running multi-container Docker applications. It allows you to configure multiple containers and their connections in a single YAML file, and then start and stop all of the containers with a single command.
For example, if you have a web application that consists of a web server, a database, and a cache server, you can use Docker Compose to define each of these components in a YAML file. You can then start all of the containers with a single docker-compose up command, and stop them with a docker-compose down command.
Here is an example of a simple Docker Compose file that defines a web application with a web server, a database, and a cache server:
version: '3.8'
services:
web:
image: nginx:latest
ports:
- "80:80"
depends_on:
- db
- cache
db:
image: postgres:latest
environment:
POSTGRES_USER: myuser
POSTGRES_PASSWORD: mypassword
cache:
image: redis:latest
This file defines three services: web, db, and cache. The web service is based on the nginx Docker image, and exposes port 80. It depends on the db and cache services, which means that they must be started before the web service can be started.
To use this Docker Compose file, you would first install Docker Compose on your system, and then run the docker-compose up command in the same directory as the YAML file. This would start the db, cache, and web containers, and connect them according to the definitions in the file.
For more information about Docker Compose and how to use it, see the Docker Compose documentation.
