Ole Michaelis & Sönke Ruempler | Jimdo

Make it SOLIDSoftware Architecture for System Administrators

OSDC 2014

Ole Michaelis“Open Source Rockstar”

@CodeStarsgithub.com/nesQuick

codestars.eu

OSDC 2014

Sönke Ruempler

“Chief Trolling Officer”

@s0enkegithub.com/s0enke

ruempler.eu

OSDC 2014

Jimdo

OSDC 2014

because infrastructure development is neither a Jenga game!

S.O.L.I.D

OSDC 2014

a little poll!

http://images.fineartamerica.com/images-medium-large/live-long-mr-spock-tobias-woelki.jpg

OSDC 2014

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S O L I D

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Adev/ops

story

Oleas

Junior Admin

SönkeasDr. Software

OSDC 2014

the basics

OSDC 2014

configuration management

IdempotentDeclarativeConvergent

Abstract

OSDC 2014

software architecture

VS.36 years

>2000 years

OSDC 2014

OSDC 2014

node web-1 {

$role = 'web-app-a'

$has_apache = true;

include php5

}

node web-2 {

$role = 'web-app-b'

$has_fcgi=true

include php5

}

# has both enabled, but needs a special config

node web-3 {

$role = 'web-app-c'

$has_fcgi=true

$has_apache=true

include php5

}

Web App 1

Web App 2

Web App 3

OSDC 2014

class php5 {

if ($::has_fcgi)

package { 'php5-cli' : ensure => installed }

}

if ($::has_apache) {

package { 'php5-apache' : ensure => installed }

}

if ($::role == 'web-app-c')

package { 'php5-web-app-c-special-module' }

file { '/etc/php5/php.ini' :

source => 'puppet:///modules/php5/php.ini-web-app-c'

}

}

}

Global variable!

Out of Context!

No abstraction

OSDC 2014

class php5(

$has_fcgi = false,

$has_apache = false,

$role = undef

) {

if ($has_fcgi)

package { 'php5-cli' : ensure => installed }

}

if ($has_apache) {

package { 'php5-apache' : ensure => installed }

}

if ($role == 'web-app-c') {

package { 'php5-web-app-c-special-module' }

file { '/etc/php5/php.ini' :

source => 'puppet:///modules/php5/php.ini-web-app-c',

require => Package[php-fcgi]

}

}

}

OSDC 2014

node 'web-1' {

$role = 'web-app-a'

$has_apache = true

class { 'php5' :

has_apache => true,

role => 'web-app-a'

}

}

node 'web-2' {

$role = 'web-app-b'

$has_fcgi = true

class { 'php5' :

has_fcgi => true,

role => 'web-app-b'

}

}

Injection!

Injection!

OSDC 2014

Would you solder a lamp directly to the electrical wiring in a

wall?

Dependency Inversion

OSDC 2014

OSDC 2014

class php5(

$has_fcgi = false,

$has_apache = false,

$role = undef

) {

if ($has_fcgi)

package { 'php5-cli' : ensure => installed }

}

if ($has_apache) {

package { 'php5-apache' : ensure => installed }

}

if ($role == 'web-app-c') {

package { 'php5-web-app-c-special-module' }

file { '/etc/php5/php.ini' :

source => 'puppet:///modules/php5/php.ini-web-app-c'

require => Package[php-fcgi]

}

}

}

OSDC 2014

Stuff tends to get big

Beware of god classes!

OSDC 2014

if ($lighttpd) { package { 'php5-cgi': } configdir { '/etc/php5/cgi': require => Package['php5-cgi'] } configdir { '/etc/php5/cgi/conf.d': require => Package['php5-cgi'] } if ($testserver) { configfile { '/etc/php5/cgi/php.ini': sourcename => 'php5/cgi/php.ini-testserver', require => Package['php5-cgi'] } } else { if ($cms ) { configfile { '/etc/php5/cgi/php.ini': sourcename => 'php5/cgi/php.ini-cms', require => Package['php5-cgi'] } } else { if ($mgmt ) { configfile { '/etc/php5/cgi/php.ini': sourcename => 'php5/cgi/php.ini-mgmt', require => Package['php5-cgi'] } } else { if ($lc ) { configfile { '/etc/php5/cgi/php.ini': sourcename => 'php5/cgi/php.ini-lc.jimdo.com', require => Package['php5-cgi'] } } else { configfile { '/etc/php5/cgi/php.ini': sourcename => 'php5/cgi/php.ini', require => Package['php5-cgi'] } } } } } configfile { '/etc/php5/cgi/conf.d/pdo.ini': sourcename => 'php5/cgi/conf.d/pdo.ini', require => Package['php5-cgi'] } }

OSDC 2014

OSDC 2014

?

OSDC 2014

OSDC 2014

rspec-puppet

test-kitchen

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OSDC 2014

describe :node => 'web-1' do it { should contain_package('php5-fcgi') }end

describe :node => 'web-2' do it { should contain_package('php5-apache2') }end

describe :node => 'web-3' do it { should contain_package('php5-fcgi') } it { should contain_package('php5-apache2') }end

Test php5 class:Install Package

?

OSDC 2014

describe :class => 'php5::fcgi' do it { should contain_package('php5-cli') }end

describe :class => 'php5::apache' do it { should contain_package('php5-apache2') }end

class php5::fgci { package { 'php5-cgi' : ensure => installed }} class php5::apache { package { 'php5-apache' : ensure => installed }}

OSDC 2014

Just because you can, doesn’t mean you

should!

Single Responsibility

OSDC 2014

describe :node => 'web-1' do it { should include_class('php5::fcgi') } it { should contain_package('php5-fcgi') }end describe :node => 'web-2' do it { should include_class('php5::apache') } it { should contain_package('php5-apache2') }end

node web-1 { include php5::apache} node web-2 { include php5::fcgi}

Tests

Code

OSDC 2014

OSDC 2014

“programs […] are changed by adding new code, rather than by changing

existing code”

Open ClosePrinciple

OSDC 2014

OSDC 2014

new requirements...now web app 1 needs a second

node

node web-1 { $role = 'web-app-a' include php5::apache}

node web-1a { $role = 'web-app-a' include php5::apache}

OSDC 2014

OSDC 2014

OSDC 2014

class role::web-app-a { include php5::apache}

node web-1 { include role::web-app-a} node web-1a { include role::web-app-a}

Our new role!

And nodes just include it!

OSDC 2014

>

OSDC 2014

OSDC 2014

?class php5::fcgi($role = undef) {

if ($role == 'web-app-c') {

package { 'php5-web-app-c-special-module' }

file { '/etc/php5/php.ini' :

source =>

'puppet:///modules/php5/php.ini-web-app-c',

require => Package[php-fcgi]

}

}

}

OSDC 2014

Don’t call us,we call you!

Hollywood Principle

OSDC 2014

class role::web-app-c::special-php-stuff { package { 'php5-web-app-c-special-module' } file { '/etc/php5/php.ini' : source => 'puppet:///modules/php5/php.ini-web-app-c' }}

1. Split out the special case into its own class.

OSDC 2014

class php5::fcgi($include_after_package_install = undef) { package { 'php5-fcgi' : ensure => installed } if ($include_after_package_install) include $include_after_package_install Package['php5-fcgi'] -> Class[$include_after_package_install] }}

2. Make the special case pluggable and reusable.

2a. And name it abstract.

OSDC 2014

class role::web-app-c { include php5::apache class { 'php5::fcgi' : include_after_package_install => 'profile::web-app-c::special-php-stuff' }}

3. Pass the special case as dependency in our web-app-c.

OSDC 2014

OSDC 2014

class profile::web-app-c::special-php-stuff { package { 'php5-web-app-c-special-module' } file { '/etc/php5/php.ini' : source => 'puppet:///modules/php5/php.ini-web-app-c' }} ?

OSDC 2014

define php5::specialconfig( $ensure = present, $sapi, $module, $key, $value, $section = undef, $path = '/etc/php5/%s/conf.d/%s.ini') { ini_setting { $title: ensure => $ensure, path => sprintf($path, $sapi, $module), section => $section, setting => $key, value => $value, require => Package["php5-${sapi}"] }}

OSDC 2014

OSDC 2014

?

OSDC 2014

“puppet separate code and data”

I’m feeling lucky

OSDC 2014

# /etc/puppet/hieradata/web1.yaml---classes:- profile::web-app-a # /etc/puppet/hieradata/web1a.yaml---classes:- profile::web-app-a # /etc/puppet/hieradata/web2.yaml---classes:- profile::web-app-c # /etc/puppet/hieradata/web3.yaml---classes:- profile::web-app-c

puppet-hiera

example in YAML

OSDC 2014

node default { hiera_include('classes')}

node web-1 { include role::web-app-a} node web-1a { include role::web-app-a}

node web-2 { include role::web-app-b}

node web-3 { include role::web-app-c}

OSDC 2014

hiera

AWS/Cloudformation LDAP

DNSyour selfwritten stuff

OSDC 2014

OSDC 2014

OSDC 2014

OSDC 2014

What about I and L

in SOLID?

OSDC 2014

You want me to plug this in, where?

Interface Segregation

OSDC 2014

If it looks like a duck, quacks like a duck, but

need batteries - you probably have the wrong abstraction!

Liskov Substitution

OSDC 2014

S O L I D

OSDC 2014

OSDC 2014

Structure your code!Node

ProfileProfilesRole ProfileModules

Resources

OSDC 2014

Puppet forge

puppet module registry

OSDC 2014

Librarian Puppetr10k

Berkshelf (chef)

OSDC 2014

stdmod

https://github.com/stdmod

OSDC 2014

sandboxeddevelopment

https://github.com/mlafeldt/skeleton-cookbookhttps://github.com/Jimdo/puppet-skeleton

OSDC 2014

server spechttp://serverspec.org/

beaker(puppet)

https://github.com/puppetlabs/beaker

OSDC 2014

Thank you!

OSDC 2014

@CodeStarsole@jimdo.com

@s0enkesoenke@jimdo.com

Questions?

OSDC 2014

*I ’m just a blank slide*

OSDC 2014

Sources• http://www.slideshare.net/PuppetLabs/garethrushgrove-puppetconf• http://www.slideshare.net/PuppetLabs/alessandro-franceschi-new• https://github.com/jedi4ever/stop-the-fork• http://lostechies.com/derickbailey/2009/02/11/solid-development-principles-in-motivational-

pictures/• https://speakerdeck.com/jfryman/refactoring-puppet• http://www.clker.com/cliparts/e/2/a/d/1206574733930851359Ryan_Taylor_Green_Tick.svg.med.

png• http://www.craigdunn.org/2012/05/239/• http://cdn.slashgear.com/wp-content/uploads/2012/10/google-datacenter-tech-13.jpg• http://deviq.com/Media/Default/Article/Dont-Call-Us-Well-Call-You-Jun-2013.png• http://www.timeshighereducation.co.uk/Pictures/web/g/q/g/copy_paste_keyboard_button_450.jpg• http://sanremo.com.au/wp-content/uploads/2013/05/lasagna.jpg• http://4.bp.blogspot.

com/_9kQQgQD35rY/SaV5p8YBGhI/AAAAAAAAAkg/HOvlhIo7yGI/s400/06_Red_Green_Refactor.JPG

• http://www.thelolshop.com/wp-content/uploads/2012/11/20121126-101937.jpg•