infra-as-code

Itamar Hassin April 2015
INFRASTRUCTURE
DEVELOPMENT USING
CUCUMBER, SEVERSPEC & ANSIBLE

THE GOAL
•Avoid snowﬂakes
•Fail fast (ofﬂine!) and cycle quickly
•Be able to sustain infrastructure as it expands
•Support apps and heterogeneous environments
•Optimise SA’s time (reduce manualVDDs)
•Time To Rebuild < Time To Fix

IAC, BDD, MDD
•Infrastructure As Code
•Behaviour-Driven Development
•Monitor-Driven Development

A way by which we can deﬁne, provision, and
conﬁgure hardware andVirtual Machines to suite
our needs
INFRASTRUCTURE AS CODE

An activity whereby a feature’s behaviour is described
prior to its implementation
BEHAVIOUR DRIVEN DEVELOPMENT

MONITOR DRIVEN DEVELOPMENT
• Write production monitors based on desired result
• Implement enough infrastructure to satisfy the
monitor
• Refactor
• Repeat

OURTOOLBOX
MDD Provisioning BDD IAC
ServerSpec Vagrant Cucumber Ansible

SERVERSPEC
With Serverspec, you can write tests for checking
your servers are conﬁgured correctly.

VAGRANT
Vagrant is a computer software for creating and
conﬁguring virtual development environments.

CUCUMBER
Simple, human collaboration

ANSIBLE
Ansible is a radically simple IT automation engine
that automates cloud provisioning, conﬁguration
management, application deployment, intra-service
orchestration, and many other IT needs.

SALLY & LEO AT WORK
Danielle: I want a web server.
Sally: Sure, boss.
Danielle: We’re a silo-ed org.
Sally: Sure, boss.
Danielle: The Admins need specs.
Sally: Sure, boss.
Sally: Leo, let’s pair.

WORKFLOW
How Sally and Leo go about setting up a web server
in such a way that it
•Is automated
•Is repeatable and measurable
•Assures environments for consistent development
testing

SALLY WRITES SPECS 
(IN A WORD DOC)
Feature: 
As a Webmaster (yeah baby!) I need a webserver to be
running so that I may master it. 
 
Background: 
Given my server is available 
And I provision it 
 
Scenario: 
When I get access to it 
Then I expect it to have apache running

THEY USE BDD
$ cucumber
No such file or directory @ rb_sysopen - features. Please
create a features directory to get started. (Errno::ENOENT)

MAKE FEATURES DIRECTORY
$ mkdir features

CUCUMBER IS SET UP
$ cucumber
0 scenarios
0 steps
0m0.000s

PASTE FEATURE 
(FROM WORD DOC)
Feature: 
As a Webmaster (yeah baby!) I need a webserver to be running
so that I may master it. 
 
Background: 
Given my server is available 
And I provision it 
 
Scenario: 
When I get access to it 

MISSING STEPS
$ cucumber
Feature:
As a Webmaster (yeah baby!) I need a webserver to be running so that I may master it.
Background: # features/httpd.feature:4
Given my server is available # features/httpd.feature:5
And I provision it # features/httpd.feature:6
Scenario: # features/httpd.feature:8
When I get access to it # features/httpd.feature:9
Then I expect it to have apache running # features/httpd.feature:10
1 scenario (1 undefined)
4 steps (4 undefined)
0m0.002s
You can implement step definitions for undefined steps with these snippets:
Given(/^my server is available$/) do
pending # express the regexp above with the code you wish you had
end
When(/^I provision it$/) do
pending # express the regexp above with the code you wish you had
end

WORKFLOW
At this stage, the high-level functional requirement
needs more speciﬁcation, so they MDD the server

THEY WRITE A MONITOR
describe package('apache2') do
it { should be_installed }
end
describe service('apache2') do
it { should be_enabled }
it { should be_running }
end
describe port(80) do
it { should be_listening }
end
describe file('/etc/apache2/sites-enabled/000-default.conf') do
it { should be_file }
it { should contain "example.com" }
end

MISSINGVAGRANT
A Vagrant environment or target machine is required
to run this
command.
Run `vagrant init` to create a new Vagrant
environment.
Or, get an ID of a target machine from `vagrant
global-status` to run
this command on.

THEY CREATE AVAGRANTFILE
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
config.vm.box = "Ubuntu 14.04"
config.vm.define "webserver"
config.vm.hostname = "webserver"
config.vm.network "private_network", ip: "33.33.33.33"
config.vm.provider "virtualbox" do |vb|
vb.customize ["modifyvm", :id, "--memory", "1024"]
end
end

THEY RUN MONITOR AGAIN
$ rake spec
ruby -S rspec spec/webserver/httpd_spec.rb
FFFFFF
Failures:
1) Package "apache2" should be installed
Failure/Error: it { should be_installed }
sudo dpkg-query -f '${Status}' -W apache2 | grep -E '^(install|hold)
ok installed$'
expected Package "apache2" to be installed
# ./spec/webserver/httpd_spec.rb:4:in `block (2 levels) in <top
(required)>'
2) Service "apache2" should be enabled
Failure/Error: it { should be_enabled }
sudo ls /etc/rc3.d/ | grep -- '^S..apache2' || sudo grep 'start
on' /etc/init/apache2.conf
expected Service "apache2" to be enabled
# ./spec/webserver/httpd_spec.rb:8:in `block (2 levels) in <top
(required)>'

THEY PROVISION AVM
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
config.vm.box = "Ubuntu 14.04"
config.vm.define "webserver"
config.vm.hostname = "webserver"
config.vm.network "private_network", ip: "33.33.33.33"
config.vm.provider "virtualbox" do |vb|
vb.customize ["modifyvm", :id, "--memory", "1024"]
end
config.vm.provision "ansible" do |ansible|
ansible.playbook = "playbook.yml"
ansible.inventory_path = "inventory.ini"
ansible.sudo = true
end
end

THEY RUN MONITOR
$ rake spec
There are errors in the configuration of this machine.
Please fix
the following errors and try again:
ansible provisioner:
* `playbook` for the Ansible provisioner does not exist on
the host system: playbook.yml
......
Finished in 3.51 seconds
6 examples, 0 failures

THEY WRITE PLAYBOOK
---
- hosts: all
user: vagrant
sudo: true
roles:
- common
- apache

COMMON ROLE EXAMPLE
- name: Update apt cache if needed 
apt: update_cache=yes cache_valid_time=3600 
 
- name: Upgrade OS 
apt: upgrade=dist force=yes 
 
- name: Install needed packages 
apt: pkg={{item}} state=installed 
with_items: 
- cron 
- logrotate 
- curl 
- git 
- update-motd 
 
- name: Create the deploy user 
user: name={{user}} comment="deploy user" generate_ssh_key=yes
ssh_key_bits=2048 state=present password={{password}} shell=/bin/bash 
 
- name: Set {{user}} as sudoer 
lineinfile: dest=/etc/sudoers line="{{user}} ALL=(ALL) NOPASSWD ":" ALL" 
 
- name: remove ubuntu's user 
user: name=ubuntu state=absent remove=yes

THEY WRITE INVENTORY
[webserver]
33.33.33.33

THEY RUNVAGRANT
$ vagrant provision webserver
==> webserver: Running provisioner: ansible...
PLAY [webserver] **************************************************************
GATHERING FACTS ***************************************************************
ok: [webserver]
TASK: [kamaln7.swapfile | Create swapfile] ************************************
changed: [webserver]
TASK: [common | Update apt cache if needed] ***********************************
ok: [webserver]
TASK: [common | Upgrade OS] ***************************************************
ok: [webserver]
TASK: [common | Install needed packages] **************************************
ok: [webserver] => (item=cron,logrotate,curl,git,update-motd)
TASK: [common | Create the deploy user] ***************************************
ok: [webserver]

WORKFLOW
At this stage,Vagrant and Ansible scripts provision and
conﬁgure the server, so all that’s left is to tie that to
the suspended Cucumber spec

STEP IMPLEMENTATION FOR CUCUMBER
Given(/^my server is available$/) do 
output=`vagrant reload` 
end 
 
And(/Î provision it$/) do 
output=`vagrant provision` 
end 
 
When(/Î get access to it$/) do 
run_remote("ls") 
end 
 
Then(/Î expect it to have apache running$/) do 
run_remote("ps asx | grep apache") 
end 
 
def run_remote(command) 
Net::SSH.start("33.33.33.33", "vagrant", :password => "vagrant") do |ssh| 
result = ssh.exec!(command) 
end 
end

GOODTIMES
LEO RUNSTHE MONITOR
$ rake spec
......
SALLY RUNS CUCUMBER
$ cucumber
Feature:
As a Webmaster (yeah baby!) I need a webserver to be running so that I may master it.
Given my server is available # features/steps/httpd_steps.rb:3
And I provision it # features/steps/httpd_steps.rb:8
When I get access to it # features/steps/httpd_steps.rb:12
1 scenario (1 passed)
4 steps (4 passed)

$ rake spec
......
LEO RUNSTHE MONITOR

$ cucumber
Feature:
As a Webmaster (yeah baby!) I need a webserver to be running so
that I may master it.
Given my server is available # features/steps/httpd_steps.rb:3
And I provision it # features/steps/httpd_steps.rb:8
When I get access to it # features/steps/httpd_steps.rb:12
1 scenario (1 passed)
4 steps (4 passed)
0m8.433s
SALLY RUNS CUCUMBER

AUTOMATION
• Commit the Cucumber and ServerSpec source
code to git
• Add a Jenkins task to run the scripts as part of the
integration test suite
• Add ServerSpec as a monitor in all environments
to ensure server conﬁguration immutability

SOURCE CONTROL
SCaaCC
• Infrastructure code is part of the app code
• Developers and SysAdmins share code using git
for modiﬁcations.
• HugOps can use master
• Others can use branching or forking

XP PRACTICES
• SysAdmins are part of the development team
• Participate in standups, part of a story/task
cards
• Participate in pairing sessions
• Empathise

REFERENCES
TheVisible Ops Handbook
James White's manifesto
DevOps Conferences
Ansible
Cucumber
ServerSpec

THANKYOU!
@itababy
www.in-context.com

infra-as-code

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