Docker Basics Talk

Docker.md

Docker

What is docker?

• Containerization technology at it's heart
• Lots of goodies that make containers easy to use as part of the eco-system

What problems does docker solve?

Packaging, isolation, immutability

Old Way vs. New Way: http://kubernetes.io/images/docs/why_containers.svg

Containerization vs. Virtualization

Isolation and control using Namespaces and cgroups (Containers) vs. Hardware simulation (VMs)

Namespaces

List of namespaces http://man7.org/linux/man-pages/man7/namespaces.7.html

Found in: /proc//ns

cgroups

Control Groups, used for accounting

• http://man7.org/linux/man-pages/man7/cgroups.7.html

Found in: /sys/fs/cgroups

Create mock root using unshare and namespacing

AKA Cheap container

unshare --mount --uts --ipc --pid --map-root-user --fork --user --setgroups wget http://ftp.iij.ad.jp/pub/openvz/template/precreated/centos-6-x86_64.tar.gz tar -xvf mount --rbind /etc/resolv.conf c6/etc/resolv.conf # Or alternatively create it by hand chroot cat /etc/resolv.conf

Copy-On-Write filesystem

https://docs.docker.com/engine/userguide/storagedriver/images/container-layers-cas.jpg

Practical Docker

Dockerfile

• Neat way to write up and manage dependecies for your application
• Sample docker file
• Full blown Dockerfile

Building a docker container

• docker build --tag demo:v1 .
• docker run -it demo:v1 /bin/bash

Push to registry docker push

Kubernetes

What is kubernetes ?

Container orchestration system

Why do we need it?

Makes Load balancing, Self-healing, auto-scaling, rolling-deployments easy.

Kubernetes concepts

• pods
• nodes
• replication controllers
• services

Alternative Containerization technologies

• Rkt -- https://coreos.com/rkt/
• LXC -- https://linuxcontainers.org/

The Open Container Initiative (OCI)

Initiative to unify and standardize container formats

• https://www.opencontainers.org/about
• https://github.com/opencontainers/runtime-spec

Resources

Containerization basics

• http://www.slideshare.net/jpetazzo/anatomy-of-a-container-namespaces-cgroups-some-filesystem-magic-linuxcon
• http://man7.org/linux/man-pages/man7/namespaces.7.html
• http://man7.org/linux/man-pages/man7/cgroups.7.html

Docker

• https://docs.docker.com/engine/reference/builder/
• https://docs.docker.com/engine/getstarted/
• https://docs.docker.com/engine/userguide/storagedriver/imagesandcontainers/

Kubernetes

• http://kubernetes.io/docs/whatisk8s/
• http://kubernetes.io/docs/tutorials/kubernetes-basics/

What.md

This are the informal notes from a talk delivered about Containers, Docker and Kubernetes at Tower in Nov 2016.