Docker compose¶

intro¶

tool used to define and run multi-container Docker applications on a single Docker host.
docker-swam is native container orchestration tool.
file name : docker-compose.yml
command : docker-compose up

Features¶

Service Definition: expose container and access them dn.
Multi-container Setup: Simplifies the management of multiple related containers (like a web app, database, etc.) running on the same Docker host.
Environment Variables: Supports environment variable configuration for different environments (development, production, etc.).
Networking: Automatically creates a network for the services to communicate with each other.
Volumes: Supports persistent storage via volumes and allows mounting host directories to containers.

versions :¶

version-3 **¶

example
will start the nginx web server and the PostgreSQL database,
linking them through the custom network : webnet.

You can access the web service by navigating to http://localhost:8080

version: '3.8'

services:
  web:
    image: nginx:latest
    container_name: nginx-web
    ports:
      - "8080:80"  # Maps port 8080 on the host to port 80 on the container
    volumes:
      - ./html:/usr/share/nginx/html  # Mounts the local 'html' folder to the container
    networks:
      - webnet

  db:
    image: postgres:latest
    container_name: postgres-db
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mydatabase
    volumes:
      - db-data:/var/lib/postgresql/data  # Persist database data
    networks:
      - webnet

networks:
  webnet:
    driver: bridge

volumes:
  db-data:
    driver: local

version-2¶

by default create one network ( name:current_dir_default ) and associate all containers with it.
services:
- container-name-1 :
  - link not needed, already link all container/s (within default n/w) with each other.
  - for external network can add link.
- container-name-1 :
- depends on :
- network/s:
  - network-1
  - network-2
  - one container can be associated with multiple networks
networks:
- can also create
- network-1
- network-2

version-1¶

container-name-1 :
- image or build :
- ports:
- environment:
  - ENV_1: xxxxx
  - ENV_2: xxxxxx
- link:
  - db:db or just db, which become hostname.
  - redis:rd
container-name-2 :
container-name-3 :
note: sequence of container matters. v2 has depends-on.