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Notes from Mosh's Docker Tutorial ​

Docker Tutorial for Beginners [2021] - YouTube

  1. What is Docker?
  2. Virtual Machines (VMs) vs Containers
  3. Docker Architecture
  4. Development Flow
  5. Development Flow Example
  6. Additional Vocab
  7. Kernel
  8. Dockerfile
  9. Image
  10. Container
  11. Docker Commands

What is Docker? ​

  • Docker is a platform for building, running, & shipping apps
  • Docker acts as a buffer between the App's environment & local machine
  • i.e., provides consistently
  • Container = Isolated environment for each app
    • Contains Config Files, Dependencies, etc.
    • Containers are easy to create & delete since they are isolated!

Virtual Machines (VMs) vs Containers ​

  • Containers = isolated environment for running an App
    • Containers are more lightweight since they use the host's OS (specifically the host's kernel)
  • VMs = recreates a whole machine (OS, license, etc.)
    • VMs consume more resources

Docker Architecture ​

  • Docker's Type: Client-Server Architecture
  • Client -> {REST API} -> Server(Docker Engine)
  • Docker Engine creates & manages the containers
  • Containers are special processes running on the host OS
    • Special b/c Containers contain their own file system
  • Containers use the host's kernel
    • Windows -> Docker can run Windows & Linux Containers
    • Linux -> Docker can run Linux Containers
    • Mac -> Docker runs Linux VM that runs Linux Containers

Development Flow ​

  • Docker-ize an App? -> Add a Dockerfile to the App
  • Dockerfile + App -> Image
  • Tell Docker to start a Container using the Image
  • Upload Images to Docker Hub
    • Registry for Docker Images (similar to GitHub)

Development Flow Example ​

Instructions for Docker -> Dockerfile

  1. Start with an OS
  2. Install Node
  3. Copy app.js
  4. Run node app.js

Additional Vocab ​

Kernel ​

  • manages Apps & hardware resources
  • Inside OS

Dockerfile ​

  • plaintext file
  • Instructions for Docker to package the App into an Image

Image ​

  • Contains everything the App needs to run
  • Includes
    • Cut-down OS
    • runtime environment (eg. Node)
    • Application files
    • 3rd party libraries
    • Environment variables

Container ​

  • Containers are special processes running on the host OS
    • Special b/c Containers contain their own file system
  • Isolated environment for each app
    • Includes Config Files, Dependencies, etc.
    • Easy to create & delete
  • Containers use the host's kernel
    • Windows -> Docker can run Windows & Linux Containers
    • Linux -> Docker can run Linux Containers
    • Mac -> Docker runs Linux VM that runs Linux Containers

Docker Commands ​