DevOps aims to break down barriers between development and operations through practices like continuous integration and deployment. This involves automating the deployment process, testing in environments that match production, and making regular deployments to production. Enabling technologies for DevOps include configuration management tools like Ansible and Vagrant, and containerization with Docker.

1. DevOps: What is it and why is it important?
Mark Stillwell
September 28, 2014

2. Traditional Development/Deployment best practices
I source code only in vcs
I static release as versioned archive
I unit testing of code in development environment
I

3. nal product not installed on developer machine
I deployment instructions via howto or interactive application
I time consuming
I dicult to replicate

4. Similar Work
ows
I Collaborating on a paper by emailing Word .doc

5. les
I Developing software without vcs, periodically creating
versioned/dated zip

6. le in a backup/ directory

7. Issues With These Approaches
I Coordination, Communication, Documentation:
I I'll edit the document and email you when I'm done.
I I had to tinker with /etc/foo to get things working.
I Handling of con
icts
I No automating of merges
I Lack of one true authoritative latest version.
I Culture of Fear
I I know generally what needs to be done, but I'm afraid to try
because I might break it and not be able to get things working
again.

8. Software Speci

9. c Issues
I Diculty verifying complicated interaction between multiple
parts.
I Brittle deployment: It works, mostly, but don't touch it!
I Experts-Only install discourages end-users, results in lower
adoption/mindshare.

10. DevOps
I deployment as code in vcs
I continuously tested
I test environment similar to deployment environment
I enabled by virtual machines and containers
I regular deployments to production
I industry standard practice!
I NetFlix, Etsy, Twitter, etc tear down infrastructure and
redeploy multiple times per day. . .
I culture of fearless development

11. Enabling Technologies
I ansible
I vagrant
I docker

12. Ansible
I tool for managing distributed software deployments
I similar tools: puppet, chef, salt, cfengine
I free software (for command line, commercial web-based
management interface)
I written in python
I con

13. guration as list of idempotent tasks in yaml based
con

14. guration
I really only pseudo-idempotent
I push model that only requires administrator's computer have
ansible software and client machines have sshd and python
I all other require some kind of bootstrapping process on clients
I some (e.g., puppet) require server setup

15. Example Playbook
- hosts: all
sudo: True
tasks:
- name: ensure sysctl is configured
sysctl:
name: vm.swappiness
value: 10
state: present
- name: ensure latest version is installed
apt:
pkg: etckeeper
state: latest

16. Vagrant
I command line wrapper to virtualisation tools like
virtualbox/kvm
I sets up disks / networking etc.
I all con

17. guration in text Vagrant

18. le
I can bring up and network multiple vms with dierent
operating systems
I can invoke provisioning tools like ansible, or shell scripts
I user just needs to cd to right directory, type vagrant up

19. Example Vagrant

20. le
Vagrant.configure(2) do |config|
config.vm.box = ubuntu/trusty
config.vm.network forwarded_port, guest: 80, host: 80
config.vm.provider virtualbox do |v|
v.memory = 1280
end
config.vm.provision ansible do |ansible|
ansible.playbook = site.yml
end
end

21. Docker
I interface for managing container based deployments
I light-weight environment virtualisation that makes use of
linux-kernel features
I like chroot on steroids
I currently uses lxc, but this may change in the future
I also manages layered

22. le sytems using aufs copy-on-write
I disk-space ecient
I docker.io has a repository of of layers, e.g. docker pull
ubuntu
I can be used to provide lightweight linux virtual machines,
but this isn't the most ecient approach
I no need to run multiple copies of system services
I preference is one process per container, single responsibility
principle
I inter-process communication enabled by mapping directories /
ports between containers and/or host

23. Websites
I http://ansible.com
I http://vagrantup.com
I http://docker.io