Systems Building Systems
A Puppet Story

What is Puppet?
Language Parser
Client/Server
Resource Abstraction
A few other things...

Luke
Kanies
Recovering Sysadmin

One Goal:
Revolutionize
System
Administration

What is a sysadmin?

Not Exactly Modern

Do tools have
to suck?

Say What?!??

Everything the Same
Everything Distinct

“Best Practices”

Don’t look at me...
I wasn’t the last one to touch it...

SSH Cfengine ?

Bad product,
hungry Luke

SSH Cfengine ?

SSH Cfengine ?

You can either easily manage
complex systems at scale...

You can either easily manage
complex systems at scale...
Or you can’t...

Who’s using Puppet?
“...at Google we're
currently using Puppet
to manage close to
6,000 Macs, and it's
likely our deployment
will expand
dramatically beyond
that....”

Competitive Advantage

People are finally figuring out
puppet and how it gets you
to the pub by 4pm. Note that
I've been at this pub since
2pm.
-- Jorge Castro

Enter Puppet...
Configuration Is
Declarative Code
Semantics Matter
Reproducible
Shareable
Maintainable
Extensible

Developer Sysadmin

Three
people
Developer Sysadmin

An Analogy
Programming SysAdmin
Low-level, commands
Assembly
non-portable and files
Abstract,
C* Resources
portable
* For small values of
abstract

Portable Resources
This:

Portable Resources
This:
Becomes:

Portable Resources
This:
Becomes:

Portable Resources
This:
Becomes:

Portable Resources
This:
Becomes:

Portable Resources
This:
Becomes:

Portable
23 package types
Users in NetInfo,
useradd, pw
Support for Debian,
Ubuntu, Red Hat,
Solaris, OS X,
Gentoo, SuSE,
FreeBSD, and more

Debian

Debian
Red Hat

Debian
Red Hat

Package

Configuration should
Package get modified after
package installation
Configuration

Configuration should
Package get modified after
package installation
Service should restart
Configuration when
configuration changes
Service

Idempotence...

Idempotence...

Idempotence...
Describes the property of operations in mathematics
and computer science which yield the same result after
the operation is applied multiple times.

Network Effects

Code
Puppetmasterd
puppetd puppetd
OS X in the
puppetd
cloud
Linux

Every Client:

Every Client:
Retrieve resource catalog from central
server

Every Client:
Retrieve resource catalog from central
server
Determine resource order

Every Client:
Retrieve resource catalog from central
server
Determine resource order
Check each resource in turn, fixing if
necessary

Every Client:
Retrieve resource catalog from central
server
Determine resource order
Check each resource in turn, fixing if
necessary
Rinse and repeat, every 30 minutes

Every Resource:

Every Resource:
Retrieve current state (e.g., by querying dpkg
db or doing a stat)

Every Resource:
Retrieve current state (e.g., by querying dpkg
db or doing a stat)
Compare to desired state

Every Resource:
Retrieve current state (e.g., by querying dpkg
db or doing a stat)
Compare to desired state
Fix, if necessary (or just log)

Image from http://flickr.com/photos/pingnews/132543603/

Questions?
andrew@reductivelabs
twitter.com/littleidea