Docker basics-containerize applications

Docker packages applications in containers - isolated, portable environments that work on any system. No "works on my machine" problems.

Images vs containers

• Image: Template (like a class) - defines what's included
• Container: Running instance (like an object) - actual execution
• One image → many containers

Run containers

docker run -d -p 80:80 --name web nginx
# -d: detached (background)
# -p: port mapping (host:container)
# --name: container name
# nginx: image name

Build with Dockerfile

FROM ubuntu:22.04
RUN apt-get update && apt-get install -y python3
COPY app.py /app/
CMD ["python3", "/app/app.py"]

docker build -t myapp:1.0 .

Manage containers

docker ps                    # List running containers
docker stop container-name   # Stop container
docker rm container-name     # Remove container
docker logs container-name   # View logs
docker exec -it container-name bash  # Enter container

Related: aaPanel Docker | Command line

Related articles