Docker is more
than just
kernel virtualization
by Rob Richardson
About Me
Rob Richardson is a software craftsman building web properties in ASP.NET and Node, Angular and React. 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: VM++"
Docker is
- ephemeral
- isomorphic
- deterministic
Therefore Docker is
ideal platform for dev & ops
- clearly delineates duties
- clean communication strategy
Docker is
- ephemeral (short-lived)
- isomorphic (unchanging)
- deterministic (same every time)
Therefore Docker is
ideal platform for dev & ops
- clearly delineates duties
- clean communication strategy
What is Docker?
Docker is an ecosystem around Container Virtualization
What are Containers?
Light-weight kernel virtualization
What is Docker?
A suite of command-line tools for
creating, running, and sharing containers
Containers vs VMs
Source: http://www.zdnet.com/article/what-is-docker-and-why-is-it-so-darn-popular/
Containers
virtualize and share the host kernel
must match host kernel:
- Linux containers run on a Linux host
- Windows Server containers run on a Windows host
Host Docker in a VM
Docker Ecosystem
Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf
DEMO: Dockerfile
Layered Filesystem
Source: https://docs.docker.com/engine/userguide/storagedriver/aufs-driver/
Layered Filesystem
- read/write layer
-
demo
- CMD ["node" "server"]
- EXPOSE 3000/tcp
- server.js
- WORKDIR /app
-
Node
- Install Yarn
- Install Node
- Install gpg
- node user/group
-
buildpack-deps:jessie
- ... steps ...
-
parent image
- ... steps ...
-
parent image
- ... steps ...
Layered Filesystem
Only downloads each layer to disk once
because layers don't change
docker history demo
Download: https://robrich.org/slides/welcome-to-docker/docker-ecosystem.pdf
DEMO: build image, run container
Docker Magic
Inside the Container:
- A machine
- Unique IP, hostname
- Build your perfect snowflake
Outside the Container:
- A process
- Plug in power and internet
- Restart quickly
- Scale by launching more
Docker Magic
Want another?
"docker run" it again
Docker is
- - ephemeral (short-lived)
- ✔ isomorphic (unchanging)
- ✔ deterministic (same every time)
Therefore Docker is
ideal platform for dev & ops
- clearly delineates duties
- clean communication strategy