cloudstack talk

Integrating CloudStack with Puppet

Saturday, December 1, 12

About me:

Dan BodeIntegration Specialist at PuppetLabs

@bodepd

bodepd <on> freenode


Who is this talk for?

current CloudStack Users

Puppet beginners


It will cover

why integrate?

explanation of Puppet’s architecture as it applies to integration

using Puppet to model VM instances


Why Integrate?


Why integrate?

CloudStack provides an API for provisioning virtual machines

Self Service API

VM1

deployVirtualMachine


Why integrate?

Puppet converts freshly provisioned VMs into functional applications

Self Service APi

VM1

PuppetMaster

Make me anapache server

Here are theinstructions forbecoming anapache server


Why integrate?

Combined, they create fully automated application stacks.

Self Service APi

Apache1

deploy me a DB,then 2 apache servers

Apache2DB1


UnderstandingPuppet


2 run modes

puppet apply - all content is stored on the individual nodes. commonly used for testing (or for scale)

client/server - content is served from a central master (this is what we will be talking about)


A Puppet client/server run

VM1

Master

Facts Catalog

ModulesClassifier


Facter returns system specificinformation

Agent

Master

Facts Catalog

ModulesClassifier


Facter

to see a system’s facts, run

$ facterarchitecture => x86_64domain => localfacterversion => 2.0.0fqdn => DansLapTop.localhardwareisa => i386hardwaremodel => x86_64id => danbode


Facter

Nodes submit their facts as a part of the request for catalog.

Available as top scope variables from manifests

ie : $::fact_name

Creating custom facts is easy.



VM1

Master

Facts Catalog

ModulesClassifier


Modules

Sharable content composed of classes and defined resource types (configuration interfaces).


Module Forge

http://forge.puppetlabs.com/

http://forge.puppetlabs.com/puppetlabs/apache






Classes/defines compose resources


Resources

Describe the configuration state of individual system elements.

user { ‘dan’: ensure => present, shell => ‘/bin/bash’, }


Resources

Describe the configuration state of individual system elements.

user { ‘dan’: # a user named dan ensure => present, # should exist shell => ‘/bin/bash’, # with this shell }


Resources

package { ‘apache2’: # a package named apache2 ensure => present, # should be installed }


Puppet DSL and resources


Puppet DSL and Resources

The Puppet DSL can be used to compose collections of resources into classes or defined resources.


Example apache class

class apache { package { ‘apache2’: ensure => present, } file { ‘/etc/apache2/apache2.conf’: content => template(‘apache2/apache2.erb’), require => Package[‘apache2’], } service { ‘apache2’: ensure => running subscribe => File[‘/etc/apache2/apache2.conf’] }}



VM1

Master

Facts Catalog

ModulesClassifier


Classification

Process that determines how Puppet maps a role to a specific instance.


Site manifest

The master utilizes code from its site manifest to figure out how to assign a role to a node.

Master/etc/puppet/manifest/site.pp


Site manifest

Node blocks map a host’s certname to content from a module

node /^my_node/ { include apache }


Determine role based on facts

Self Service APi

Apache1

deploy me an apache server


Determine role based on facts

‘deployVirtualMachine’ -> userdata -> facts

node default { if $::role == ‘apache’ { include apache } else { fail(“Undefine role: ${role}”) }}


Decouple role assignment from provisioningAfter provisioning is completed, ssh into a machine, set a custom fact (using facts.d), and trigger a puppet run.

pros - you can easily execute a script to install and bootstrap puppet

cons - extra step


facts.d

facts.d comes with stdlib (http://forge.puppetlabs.com/puppetlabs/stdlib)

it converts any ‘key=value’ pairs listed in /etc/facts.d/*.txt into facts


http://forge.puppetlabs.com/puppetlabs/stdlib

http://forge.puppetlabs.com/puppetlabs/stdlib

ENC

The master can call out to arbitrary executables to figure out how a node should be classified.

Master

ENC


ENC

You can set the ‘group’ attribute with classification information when instances are created.

The ENC can then query the ‘group’ attribute from the VM instance that needs to be classified.



VM1

Master

FactsCatalog

ModulesClassifier


Catalog

Collection of resources that describe how a node can achieve a specified configuration.


Catalog

Catalog

Package

Package

File

UserUserFile

ServiceService

Resources

Dependencies


VM provisioning with Puppet (experimental! use cases appreciated)


Share Application Stacks as text

class my_app_stack { cloudstack_instance { 'foo4': ensure => present, group => 'role=db', }

cloudstack_instance { 'foo3': ensure => present, group => 'role=apache', }}


Use resource defaults for common settingsCloudstack_instance { image => 'CentOS 5.6 key+pass',

flavor => 'Small Instance', zone => 'ACS-FMT-001', network => 'puppetlabs-network', keypair => 'dans_keypair4',}

cloudstack_instance { 'foo4': ensure => $::ensure, group => 'role=db',}cloudstack_instance { 'foo3':

ensure => $::ensure, group => 'role=apache',}


cloudstack talk

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