ansible, simplicity, and the zen of python

Todd Owen

Ansible, Simplicity, and the Zen of Python

Koan 1

master

agent

agent

MANIFESTSSL

Puppet

for host in `cat /etc/temple_hosts` do ssh $host sudo apt-get purge puppet done

Bash

————————————————————————————————————————— / 3. Simple is better than complex. \ \ / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

>>> import this

master

agent

agent

MANIFEST SSL

for host in `cat /etc/temple_hosts` do ssh $host sudo apt-get purge puppet done

Push

Pull

SIMPLE

What is Ansible?

• IT automation tool!

• à la puppet, chef, CFEngine, salt, etc!

• Growing fast

ThoughtWorks Tech Radar

Ansible

Ansible is simple

SSHPLAYBOOK ansible

Example playbook

--- - hosts: all sudo: yes tasks: - apt: name=puppet state=absent purge=yes

-i /etc/temple_hosts

Python is simple

class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } Java

print("Hello World!") Python

————————————————————————————————————————— / 3. Simple is better than complex. \ \ / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

4. Complex is better than complicated. !!!!!

Occam’s Razor

Complex:!

• many elements!

• all necessary!

Complicated:!

• introduces unnecessary elements

Ansible Puppet

apt yum

package

apt yum

APT YUM APT YUM

module: provider:

resource type:

Complex Complicated

OS:

Python is uncomplicated

• grp (Unix)!

• winreg (Windows)!

• “…don’t cut off access to platform capabilities or properties” (Guido van Rossum)

Koan 2

hall

tree

door

corridor

room

office

templerunner.zip

src/

main/

java/

temple/

Run.java

————————————————————————————————————————— / 5. Flat is better than nested. \ \ / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

Ansible: unarchive

Python: zipfile

.NET: System.IO.Compression

Namespace

Ansible:

Python: zipfile

.NET: System.IO.Compression

unarchive

ZipFile

ZipArchive

————————————————————————————————————————— / 19. Namespaces are one honking great \ \ idea -- let's do more of those! / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

Namespace

Roles: Stouts django

cchurch django

futurice django

Koan 3

sum_fields --delim="," tally_columns

export IFS="," !!... !

————————————————————————————————————————— / 2. Explicit is better than implicit. \ \ / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

Explicit module result

tasks: - name: Verify Python 3.x is the default command: /usr/bin/python --version register: pyver failed_when: "'Python 3' not in pyver.stderr"

Magic variable?

tasks: - name: Verify Python 3 is the default command: /usr/bin/python --version register: pyver failed_when: "'Python 3' not in res.stderr"

Magic variable?

tasks: - name: Verify Python 3 is the default command: /usr/bin/python --version register: pyver failed_when: "'Python 3' not in res.stderr" ! - copy: dest=~/py.ver content="{{res.stderr}}"

Ansible and Python

Similar design philosophy!

• Simple!

• Consistent!

• Easy to learn

Ansible vision

Michael DeHaan, BDFL!

“radically simple”!

“easiest config management system to use, ever”!

— README v0.0.1

simple less!features

simple consistent!mental model

≠

=

————————————————————————————————————————— / 8. Special cases aren't special \ \ enough to break the rules. / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

–Michael DeHaan

“We’re simplifiers. We’re seeking a whole new technical aesthetic where much of the

software industry has been adrift.”

————————————————————————————————————————— / 1. Beautiful is better than ugly. \ \ / ————————————————————————————————————————— \ ^__^ \ (oo)\_______ (__)\ )\/\ ||————w | || ||

Beautiful!Python

simplicity!minimalism!pragmatism

=

todd.owen@cba.com.au!!

Analytics & Information Team, Commonwealth Bank

WE’RE HIRING!

Image Credits !

ThoughtWorks Technology Radar! ! Copyright ThoughtWorks!

Ansible Galaxy Logo!! ! ! ! ! Copyright Ansible, Inc.!

Github Avatar!! ! ! ! ! ! ! Copyright Michael DeHaan!

All other images! ! ! ! ! ! ! Public domain

Copyright !

This work by Todd Owen is licensed under a Creative Commons Attribution 4.0 International License.!