Docker Basics

Containers in practice — the commands that matter.

Core concepts

Image: blueprint (read-only)
Container: running instance of an image
Volume: persistent data storage
Compose: multi-container orchestration

Images

docker pull nginx:latest        # pull from Docker Hub
docker images                   # list local images
docker rmi <image>              # remove image
docker build -t myapp:1.0 .     # build from Dockerfile

Containers

docker run -d -p 8080:80 nginx  # run in background
docker run -it ubuntu bash       # interactive shell
docker ps                        # running containers
docker ps -a                     # all containers
docker stop <id>
docker rm <id>
docker logs <id>
docker exec -it <id> bash        # shell into running container

Volumes

docker volume create mydata
docker run -v mydata:/app/data myapp
docker run -v $(pwd):/workspace myapp   # bind mount

Compose

# docker-compose.yml
services:
  web:
    image: nginx
    ports: ["8080:80"]
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: secret

docker compose up -d
docker compose down