Ultimate Docker Course Notes

Jul 18, 2024

Ultimate Docker Course - Introduction and Basics

Course Overview

Instructor

  • Ash Hamadani
  • Taught millions on YouTube and via online school at codewithmash.com

Course Goals

  • Teach Docker from basics to advanced concepts
  • Learn how to use Docker in software development workflows
  • Comprehensive and practical lessons

Prerequisites

  • No prior Docker knowledge required
  • At least three months of programming experience
  • Knowledge of front-end, back-end, APIs, and databases
  • Familiarity with basic Git commands

Learning Methodology

  • Highly practical approach
  • Watch lessons, take notes, and practice commands
  • Recap notes and repeat the steps demonstrated

What is Docker?

Definition

  • Platform for building, running, and shipping applications consistently
  • Ensures application works the same across different machines

Common Issues in Development

  • Missing files during deployment
  • Different software versions across machines
  • Different configuration settings like environment variables

Benefits of Docker

  • Packages the application with everything it needs
  • Runs consistently on any machine with Docker installed
  • Simplifies setting up new development environments for team members
  • Isolated environments for running multiple applications with different dependencies
  • Cleaning up applications and dependencies without affecting other applications

Containers vs Virtual Machines (VMs)

Virtual Machines

  • Abstractions of physical hardware
  • Requires a hypervisor (e.g., VirtualBox, VMware, Hyper-V)
  • Each VM has a full copy of an operating system
  • Resource-intensive, slow to start, limits on the number of VMs
  • Provides complete isolation for applications

Containers

  • Lightweight, faster start-up
  • Share the host operating system (specifically the kernel)
  • Can run multiple containers with different dependencies on the same machine
  • Efficient resource utilization, can run many containers simultaneously

Docker Architecture

Client-Server Model

  • Docker Client communicates with Docker Server (Docker Engine) via RESTful API
  • Docker Engine manages building, running, and distributing containers

Containers and Kernels

  • Containers share the kernel of the host OS
  • Linux only runs Linux containers, Windows can run both Linux and Windows containers
  • Mac uses a lightweight Linux VM to run Linux containers

Setting Up Docker

Installation

  • Download and install Docker Desktop for Mac and Windows or Docker Engine for Linux
  • Upgrade to the latest version if already installed (current Docker version: 20.10.5)
  • Ensure system compatibility by checking system requirements
  • Start Docker Engine to see the Docker icon on the status bar

Running Docker

  • Verify Docker installation using docker version
  • Start interactive containers using docker run -it <image>
  • Common Docker commands: docker build, docker run, docker images or docker image ls

Development Workflow

Containerizing Applications

  • Add a Dockerfile to the application
  • Dockerfile includes instructions to package the application into an image
  • Image contains OS, runtime environment, application files, libraries, etc.
  • Push the image to a Docker registry (e.g., Docker Hub)
  • Deploy the image to any machine with Docker

Practical Example

  • Created a directory called hello_docker containing a simple app.js
  • Used a Dockerfile to define instructions for building an image
  • Followed these steps:
    1. Create a Dockerfile
    2. Specify a base image (e.g., node:alpine)
    3. Copy files to the appropriate directory
    4. Set the working directory and run commands
  • Built and ran the Docker image locally and on a remote machine
  • Demonstrated consistency of application behavior across different environments

Essential Linux Commands for Docker Users

Linux Distributions

  • Linux has many distributions (distros): Ubuntu, Debian, Alpine, Fedora, CentOS, etc.
  • Differences between distros but most commands are consistent
  • Focused on using Ubuntu

Basic Commands

  • pwd: Print working directory
  • ls: List files and directories
  • cd [path]: Change directory
  • mkdir [directory]: Create a new directory
  • touch [file]: Create an empty file
  • rm [file]: Remove a file
  • nano [file]: Open a text editor to edit files
  • cat [file]: Display content of a file
  • echo [text] > [file]: Write text to a file
  • apt-get update: Update package list
  • apt-get install [package]: Install a package
  • apt-get remove [package]: Remove a package

Viewing and Editing Files

  • Tools: nano, cat, more, less, head, and tail

Redirection

  • Use > for output redirection
  • Combine content from multiple files using cat file1 file2 > combined_file

Searching Text in Files

  • Not covered in the provided transcript but commonly done using grep