Docker is more than Kernel Virtualization

by Rob Richardson

@rob_rich . https://robrich.org/

About Me

Rob Richardson is a software craftsman building web properties in ASP.NET and Node, React and Vue. He's a frequent speaker at conferences, user groups, and community events, and a diligent teacher and student of high quality software development. You can find this and other talks on https://robrich.org/presentations and follow him on twitter at @rob_rich.

Docker is

• ephemeral
• isomorphic
• deterministic

Docker is

• ephemeral (short-lived)
• isomorphic (unchanging)
• deterministic (same every time)

What is Docker?

Docker is an ecosystem around Container Virtualization

Containers vs VMs

Source: http://www.zdnet.com/article/what-is-docker-and-why-is-it-so-darn-popular/

Containers

Containers virtualize and share the host kernel

Containers must run on the kernel for which they were built:

• Linux containers run on a Linux host
• Windows containers run on Windows Server host

Host Docker in a VM

Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf

Installing Docker

• Linux, Mac, or Windows 10:
  https://www.docker.com/get-started
• Windows Server:
  https://msdn.microsoft.com/en-us/virtualization/windowscontainers/quick_start/quick_start_windows_server

Dockerfile

FROM node

WORKDIR /app

COPY package.json .
RUN npm install

COPY . .

ENV NODE_ENV production
ENV PORT 3000
EXPOSE 3000

CMD ["npm", "start"]

Layered Filesystem

Source: https://docs.docker.com/engine/userguide/storagedriver/aufs-driver/

Layered Filesystem

source

Layered Filesystem

Volumes - non-temporary storage

Volumes are a pointer in the container
saved to a folder on the host

Volumes

In Dockerfile:

VOLUME ["/data"]

Starting container

docker run -v $(pwd):/data imagename

Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf

Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf

Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf

docker-compose.yml - configuration as code

version: '3'
services:
  web:
    build: .
    ports:
    - "80:5000"
    volumes:
    - logvolume01:/var/log
    links:
    - redis
  redis:
    image: redis
volumes:
  logvolume01: {}

Source: https://docs.docker.com/compose/overview/

Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf

Docker Magic