Puppet Camp Berlin 2014: Module Rewriting the Smart Way

© Martin Alfke - 2014
Module (Re)writing the
Smart Way
Martin Alfke

<martin.alfke@buero20.org>

!
Puppet Camp Berlin 2014
www.netways.de/puppetcamp
Check-In / Schedule
Please provide your name or a form of identification at the conference registration desk.
Location

About Me
• Freelancer - Berlin/Germany

• Automation and Cfg Mgmt

• PCP 2013

• Module Contributor

• PuppetLabs Partner
Martin Alfke - at home

What is this talk about?
The story of ﬁnding a module,
learning that it is not useful for
you, rethink and rewrite new
shared, public module from
scratch use it in your private
roles and proﬁles and maintain it
for other users.
Martin Alfke - SFO -Vesuvio Cafe

What else?
Why contributing is better than
building a golden porcelain tower in
the dark of your closet.

or

The Puppet community way of
getting a task done.
Martin Alfke - Berlin - Hotel du Rome

The Task
Yes, we will have that task
ﬁnished by yesterday !
http://www.mid-day.com/articles/day-29-in-bigg-boss-6-its-vrijesh-vs-major-sidhu/187949

How to start?
We build a Puppet module !!

!
But … how should we start?
http://designtaxi.com/article/101902/How-To-Start/

The Lone Warrior Way
Martin Alfke - Lassen County, California

Coding Puppet …
class webserver13 {
package { 'apache2': ensure => present, }
file { '/etc/apache2/sites-enabled/000-default':
ensure => absent,
}
file { '/etc/apache2/sites-available/10_webserver13':
ensure => file,
source => 'puppet:///modules/webserver13/10_webserver13',
}
file { '/etc/apache2/mods-enabled/alias.conf':
ensure => link,
target => '/etc/apache2/mods-available/alias.conf',
}
file { '/etc/apache2/mods_enabled/alias.load':
ensure => link,
target => '/etc/apache2/mods-available/alias.load',
}
...
}

Documentation / Bugﬁxes
Who is doing reviews?

☞

YOU

Who does documentation?

☞

YOU

Who will support you?

☞

YOU
http://lonewarriorswa.com/

Features? Changes?
poor lonesome cowboy

I’m a poor lonesome cowboy

I'm a long long way from home

And this poor lonesome cowboy

Has got a long long way to roam

Over mountains over prairies

From dawn till day is done

My horse and me keep riding

Into the setting sun

http://smellslikescreenspirit.com/2009/12/warner-bros-2010-preview/Poor lonesome cowboy - Pat Woods

The Smart Way
Is there something available?

DevOps means to understand and
reuse foreign code.

Use Puppet as a framework.
http://www.thindifference.com/2011/02/11/what-is-the-best-way-to-brand-the-middle/

You are not alone
There are:

- companies using the same technology

- developers using the same framework

- sites which collect informations

- people talking about their solution
http://clivehicksjenkins.wordpress.com/

Sources
puppetlabs.com
github.com
http://en.wikipedia.org/wiki/File:Microsoft-Staff-1978.jpg

Found the solution?
Give feedback

Cooperate / Fix bugs / Improve
http://www.positoons.de/leistungen/character-design-info/eierlegende-wollmilchsau/

Reusing Modules
class webserver13 {
class { ‘::apache’:
default_vhost => false,
default_mods => false,
}
include ::apache::mod::alias
...
}

Reality?
We were checking for a module for
cloud management

We found one

We talked to upstream:

“Oh, …, yes, …, this module, …, ahem,
…, do yourself a favour, …, rewrite it”

or

What if you found nothing?
http://technorati.com/entertainment/celebrity/article/the-12-steps-of-reality-tv/

Start Writing Public Code
Start a shareable, parameterised
generic module

Always keep in mind separation of code
and data

Let others decide which data source
they want to use.

Do never put private data in your repo

Start using public repo immediately

Take care on proper license (AGPL,
GPL,…)
http://www.security-faqs.com/why-your-company-
should-issue-open-source-security-packages.html

Combine Public/Private
Use your public module like any other
(e.g. puppetlabs apache)

Add data only to your private
(wrapper) module

Search for “Puppet Roles and Proﬁles”
to understand this separation
http://www.internetmarketinginc.com/blog/share-or-not-share-
thats-the-question-going-public-with-private-information/

Responsibility
Be a responsive upstream

Always remember that other people
might want to solve similar problems
(not identical)

Make your code run on different
platforms

Build a community around your module

Review Pull Requests in time
http://ryaneller.com/guest-post/guest-post-friday-the-power-of-responsibility/

Improvement
Take your time to implement or
merge improvements

Write test

Write good documentation and
usage examples

Write more tests

Use your code

Summary - 1
Work smart, not hard

Write good documentation, examples and
tests

Write blog posts (mention your module
and company)

Be a responsive and responsible upstream

Review other users contribution

Allow access if contributors code quality
ﬁts your requirements
Martin Alfke - SFO

Summary - 2
Never refactor

Restart prevents old bugs in new
module

There will always come more
requirements

Parameters, parameters, parameters

Let other users decide for their
preferred data source

Use a proper open source license
Martin Alfke - SFO

Summary - 3
K.I.S.S

(Keep it simple and stupid)

“perfection is achieved, not when there
is nothing more to add, but when there
is nothing left to take away.”

(Antoine de Saint-Exupéry)
Martin Alfke - SFO

www.netways.de/puppetcamp
Check-In / Schedule
Please provide your name or a form of identification at the conference registration desk.
Location

PuppetForge

PuppetForge - ?

PuppetForge - 2

PuppetForge - yea

GitHub - woo

GitHub - Module must
haves

Puppet Camp Berlin 2014: Module Rewriting the Smart Way

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