Docker

Motivation

• As DevOps I want to quickly spin up a new server
• As DevOps I want to change the setup for all existing servers / part of them / new servers
• As DevOps I want to test the env changes before actually applying them
• As DevOps I want to run different stack components versions on the same server (e.g. panda)
• As a developer I want to reproduce "only at the server" bug.
• As a developer I want to setup a new dev env

Meet Docker...

• Virtualization alternative
• Linux containers based
• Fast growing technology

Introduction to Docker

Basics

Try It

• Images - transportation mean
• Containers - execution mean
• Dockerfile (remember Vagrantfile?)
• Docker Hub - Registry

Examples

• docker run ubuntu:14.04 /bin/echo 'Hello world'

• docker ps (-a)

• docker kill
• docker rm
• docker pull

• docker build

• docker images

• docker rmi

• docker push

• Dockerfile syntax

Our Need

• Setup Server 12 from top to bottom

• Based on the prescription we have

  • Some components required as is

  • Some components will go through config change

  • Some components are not required anymore

• Proudly invented elsewhere...

  • Is there a ready made image? Not really

  • Can we re-use some image as a baseline

Our Image Evolution - 1

• First take: build a full stack image:

  • Centos

  • Hardening, users, sshd

  • Firewall, Antivirus, rkhunter, etc

  • LAMP

  • Backup, monitor, logging

  • ...

• Second take: Different Envs - Different Needs

  • Separate Prod from Dev

  • Re-use as much as possible => base-image

  • TODO: change config files instead of copying

Our Image Evolution - 2

• Third take: separation of concerns

  • Desirably container per service

  • Linking containers

  • MySQL container + HTTPD Container

  • Restriction: image derivation is not possible

  • Both containers use the same Prod-Image

• Fourth take: data persistency

  • Setting up data volumes

  • var/www/html volume

  • mysql volume

  • config volume

Our Image Evolution - 3

• Fifth take: Orchestration

  • Need a tool to manage the containers

  • Meet fig AKA docker-compose

  • docker-compose.yml 

• Future Evolution:

  • Near term

    • Containers for additional services

    • Hardening the host

  • Longer term

    • Containers per site-service (i.e. pandora httpd)

    • No SSHD?

    • Own Registry

Additional Tools

• Docker hub - registry (for running)
• Bitbucket - images code (for building)
• Windows - special as always
  • VirtualBox+Boot2Docker
  • VirtualBox+Vagrant... + <some distro>
  • See this