Complete Docker Course Notes 🐳

Course Overview

• Course Content:
  • Theoretical explanations and hands-on demos to gain hands-on experience with Docker.
• Main Topics:
  • Introduction to Docker
  • Docker vs. Virtual Machines
  • Installing Docker
  • Managing Containers
  • Docker Workflow with a Demo Project
  • Docker Compose
  • Dockerfile and Building Docker Images
  • Pushing Docker Images to Private Repositories
  • Deploying Containerized Applications
  • Data Persistence in Docker using Volumes

Introduction to Docker

• What is Docker:
  • Tool for packaging applications with dependencies and configuration.
• Problems Solved by Docker:
  • Portability and isolation of applications, simplifies both development and deployment processes.
• Containers vs. Virtual Machines:
  • Containers virtualize the application layer and share the host OS kernel.
  • VMs virtualize the entire OS, including the kernel, leading to larger size and slower startup.

Practical Usage of Docker

• Starting and Stopping Containers:
  • Use docker run to pull and start containers.
  • Use docker stop and docker start to manage running containers.
• Port Binding in Docker:
  • Bind container ports to host ports using -p flag.
• Docker Networks:
  • Containers in the same Docker network can communicate using container names.
• Inspecting Containers:
  • Use docker logs to view logs.
  • Use docker exec to access container terminals for debugging.

Docker Compose

• Purpose:
  • Simplify running multi-container Docker applications.
• Composing Services:
  • Define services in a docker-compose.yaml file.
  • Use docker-compose up to start all services and docker-compose down to stop them.
• Networking in Docker Compose:
  • Automatic network creation, allows containers to refer to each other by name.

Building Docker Images

• Dockerfile Basics:
  • Blueprint for creating Docker images.
  • Specify base image with FROM and add application dependencies and code.
  • Use RUN to execute commands and COPY to include local files.
  • Define entry point with CMD.
• Building Images:
  • Use docker build to create an image.
• Tagging and Pushing to Repositories:
  • Tag images with repository address before pushing.
  • Use docker push to upload images to repositories (e.g., AWS ECR).

Deploying Docker Applications

• Using Docker Compose for Deployment:
  • Combine application and dependent containers in docker-compose.yaml.
  • Deploy by running docker-compose up.
• Data Persistence:
  • Use Docker volumes to persist data across container restarts.
  • Mount host directories into containers using volumes.

Docker Volumes

• Purpose and Types of Volumes:
  • Persist data between container restarts.
  • Types include Host Volumes, Anonymous Volumes, and Named Volumes.
• Defining Volumes in Docker Compose:
  • Use volumes attribute to map host directories to container paths.
• Inspecting Volumes:
  • Named volumes managed by Docker and stored under /var/lib/docker/volumes.

Additional Notes

• Common Commands:
  • docker pull [image]: Pull an image from a registry.
  • docker run [options] [image]: Run a container from an image.
  • docker stop [container_id]: Stop a running container.
  • docker start [container_id]: Start a stopped container.
  • docker ps [-a]: List running (or all) containers.
  • docker images: List local images.
  • docker logs [container_id]: View container logs.
  • docker exec -it [container_id] [command]: Run a command in a running container.
  • docker rm [container_id]: Remove a stopped container.
  • docker rmi [image_id]: Remove an image.
  • docker-compose up [-d]: Start containers as defined in docker-compose.yaml.
  • docker-compose down: Stop and remove containers, networks, volumes defined in docker-compose.yaml.

Conclusion

• Next Steps: Learn about container orchestration tools like Kubernetes. Check out tutorials and subscribe to the channel for more content on modern development tools.
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