Docker for Beginners Lecture Notes

Introduction to the Course

• Instructor: Moonshot 100, a DevOps and cloud trainer at Code Cloud Comm.
• Experience: Over 13 years in the industry, training thousands of students.
• Course Format: Interactive lectures with animations, illustrations, and hands-on labs accessible from your browser.

Course Objectives

• Understand containers and Docker basics.
• Learn how to run a Docker container and build your own Docker image.
• Explore Docker networking and Docker Compose.
• Introduction to Docker registry and private registry deployment.
• In-depth understanding of how Docker works under the hood.
• Overview of Docker for Windows and Mac.
• Basics of container orchestration with Docker Swarm and Kubernetes.

Hands-On Labs

• Provided labs accessible via browser for practical experience.
• Instant access to a terminal and quiz portal to validate your work with immediate feedback.

Real-World Application of Docker

• Personal experience with Docker for setting up application stacks with Node.js, MongoDB, Redis, etc.
• Challenges of compatibility across services and OS versions.
• Simplifying development environment setup for new developers.

Understanding Containers

• Containers: Isolated environments with their own processes and dependencies, sharing the same OS kernel.
• Docker utilizes Linux containers (LXC).
• Containers are not new; they've existed for around 10 years.
• Setting up low-level container environments is complex; Docker simplifies it.

Operating System Basics

• OS consists of a kernel and software.
• Docker can run flavors of Linux on a single kernel (e.g., running Ubuntu, Debian, etc. on the same kernel).
• Windows does not share the same kernel with Linux containers.

Differences between Containers and Virtual Machines

• Containers share kernel, are lightweight (usually in MBs), and boot up quickly (seconds).
• Virtual machines have separate OS instances, heavier (in GBs), and take longer to boot (minutes).
• Containers have less isolation, but both containers and VMs can coexist for better resource utilization.

Docker Images vs. Containers

• Images: Packages/templates for creating containers. Containers are running instances of images.
• Docker Hub: Public repository for Docker images.
• Custom images can be created and shared via Docker Hub.

Getting Started with Docker

• Docker editions: Community Edition (free) and Enterprise Edition (paid with enterprise features).
• Installation for Linux, Mac, and Windows.

Basic Docker Commands

• docker run: Launches a container.
• docker ps: Lists running containers.
• docker stop: Stops a running container.
• docker rm: Removes a stopped container.
• docker images: Lists downloaded images.
• docker rmi: Removes an image.

Container Lifecycle

• Containers exit once the process completes (e.g., running Ubuntu exits immediately because no process).
• Persistent data can be managed with data volumes.

Networking in Docker

• Docker creates three networks: Bridge, Host, and None.
• Containers communicate through internal IPs or mapped ports.

Advanced Docker Features

• Docker Compose: Manage multi-container applications using YAML files.
• Different versions of Docker Compose files (v1, v2, v3) enable new features such as service dependencies and custom networks.

Docker Registry

• Central repository for Docker images.
• Docker Hub is the default registry, but private registries can be set up.
• Docker registry can be run as a container itself.

Docker Engine Architecture

• Components: Docker daemon, REST API server, and CLI.
• Namespaces and control groups (cgroups) provide process and resource isolation.

Docker on Windows and Mac

• Docker Toolbox: Legacy version using VirtualBox for running Docker on Windows/Mac.
• Docker Desktop: Uses native virtualization (Hyper-V for Windows, HyperCard for Mac) for better performance.
• Supports running Linux containers; Windows containers are available on Windows Server.

Container Orchestration

• Definition: Automatic management of deploying, scaling, and operating application containers.
• Container orchestration tools include Docker Swarm and Kubernetes, providing load balancing, scaling, and high availability.
• Kubernetes is the most popular orchestration tool, supporting multi-cloud environments.

Conclusion

• The course covered Docker fundamentals, hands-on labs, commands, and orchestration.
• Further courses are available for deeper learning in advanced Docker, Kubernetes, and associated DevOps tools.