basics

Docker is a platform for developing, shipping, and running applications in containers. Containers allow you to package an application and its dependencies together in a standardized unit for easy deployment across different environments. Here are some basics to get you started with Docker:

1. Install Docker:

• Install Docker on your machine by following the instructions on the official Docker website.

2. Docker Concepts:

• Image: A lightweight, standalone, and executable package that includes everything needed to run a piece of software, including the code, runtime, libraries, and system tools.

• Container: An instance of a Docker image, running as a process on the host machine.

3. Docker Commands:

• Pull an Image:

  docker pull image_name:tag

• Run a Container:

  docker run image_name:tag

• List Running Containers:

  docker ps

• List All Containers (including stopped ones):

  docker ps -a

• Stop a Running Container:

  docker stop container_id

• Remove a Container:

  docker rm container_id

• List Docker Images:

  docker images

• Remove an Image:

  docker rmi image_id

4. Dockerfile:

• Create a Dockerfile to define how your image should be built. Here's a basic example:

  # Use an official base image
  FROM nginx:latest
  
  # Copy your application code
  COPY . /usr/share/nginx/html
  
  # Expose a port
  EXPOSE 80
  
  # Define the command to run your application
  CMD ["nginx", "-g", "daemon off;"]

5. Build a Docker Image:

• Navigate to the directory containing your Dockerfile and run:

  docker build -t image_name:tag .

6. Run a Container from a Built Image:

• After building your image, run a container:

  docker run -p 8080:80 image_name:tag

This example maps port 8080 on your host machine to port 80 in the container.

7. Docker Volumes:

• Use volumes to persist data outside the container:

  docker run -v /path/on/host:/path/in/container image_name:tag

8. Docker Compose:

• Docker Compose allows you to define and run multi-container Docker applications. Create a docker-compose.yml file to specify services, networks, and volumes.

9. Networking:

• Docker containers can communicate with each other using container names or through defined networks.

10. Docker Hub:

• Docker Hub is a registry service where you can find and share container images.

11. Docker Cheat Sheet:

• Refer to the official Docker Cheat Sheet for quick reference.

Additional Resources:

• Docker Documentation

• Docker Getting Started

Practice running containers, building images, and exploring more advanced features as you become more comfortable with Docker. It's a powerful tool for containerization and can significantly simplify application deployment and management.