The document discusses the history and evolution of the "pets vs cattle" metaphor for describing how servers are managed. Originally, servers were treated like pets that were individually cared for, but in modern cloud computing they are treated like cattle in a herd that can be replaced without individual attention when one goes down. This shift reflects how infrastructure has become automated, standardized and able to dynamically scale out on demand. The metaphor helped explain why cloud computing was different from traditional IT and how failures could be handled without impact.

1. The History of
Pets vs. Cattle
Randy Bias
Vice President
September 30, 2016
OpenStack Days Seattle
@randybias
… & Using It Properly

2. Once upon a
time …
2

3. Cloud was Hard to Explain
3

4. It Wasn’t Really About Buying Online Services
4
2012
How to explain … ???
It’s got to be simple. Dead
simple.

5. I Went Looking for Inspiration
5
Bill Baker had a genius explanation
for scale-out vs. scale-up

6. So I, um … Appropriated It
6
Randy Bias

7. And a Meme was Born…
7

8. How to Explain Why Cloud is Different
8
Hint: it’s about uniqueness

9. “
”
In the old way of doing things, we treat
our servers like pets. For example,
‘Frodo’ the mail server. If Frodo goes
down, it’s all hands on deck. The CEO
can’t get his email and it’s the end of
the world.
In the new way, servers are numbered,
like cattle in a herd. For example,
www001 to www100. When one server
goes down, it’s taken out back, shot,
and replaced on the line.
— Randy Bias (many hundreds of times from 2012-2016)
9

10. The Old Way: Assembly Line IT

11. 11
“Mode 1”, “The Second Platform”, “Legacy”
GUI Driven
Ticket Based
Hand Crafted
Reserved
Scale-Up
Smart Hardware
Proprietary
“Waterfall Ops”
. . .

12. Each Server Built This Way is A “Pet”
12
“I love you!”
• Unique & indispensable
• Hand fed, hand-crafted
• Examples:
–mainframes
–HA pairs (LB, firewall, etc.)
–master/slave databases
• A “herd” of cattle is not 2 servers

13. The New Way: Robotics Factory IT

14. “Mode 2”, “Third Platform”, “Cloud-Native”
API Driven
Self Service
Automated
On Demand
Scale-Out
Smart Apps
Open Source
Agile DevOps
. . .

15. Every Server is Just Another Part of the Herd
15
“Lunch!”
• “A herd” is just many homogeneous servers
• 100% automated & designed to fail
• Load balanced & multi-master
• LB: svc discovery, DNS, H/W LB
• Examples:
- web server arrays
- multi-master data stores (Cassandra)
- Hadoop clusters

16. Pets vs Cattle
16
GUI Driven
Ticket Based
Hand Crafted
Reserved
Scale-Up
Smart Hardware
Proprietary
“Waterfall Ops”
. . .
API Driven
Self Service
Automated
On Demand
Scale-Out
Smart Apps
Open Source
Agile DevOps
. . .
Disposable,
One of the
Herd
Unique and
Indispensable

17. Our Brave New World
17
• Failures happen … always
• Everything must fail without an
impact: server components,
servers, racks, datacenters …
everything
• And most importantly, apps
must detect and route around
these failures

18. The Fundamental Difference
18
The Old Way
(inelastic)
The New Way
(elastic)
99.9%
Applications
99.999%
Infrastructure
($$$$)
99.999%
Applications
99.5%
Infrastructure
($)
Responsibility
Shift

19. Extending the Meme … Muddies the Water
19

20. An Example: Kubernetes “Pet Sets”
20
Stateful Applications supported by “Pet Sets”
• Cassandra
• Kafka
• MongoDB
These are
Cattle-architected
data store systems
Source: K8s Blog: Stateful Applications in Containers!? Kubernetes 1.3 Says "Yes!”

21. The World’s Biggest Stateful System is …
21Cattle … All the Way Down

22. Getting Value from “Pets vs Cattle”
22

23. Respect the Meme
23
See Also:
• http://tinyurl.com/history-pets-cattle
• http://www.slideshare.net/randybias/pets-vs-cattle-the-
elastic-cloud-story
• http://www.lauradhamilton.com/servers-pets-versus-cattle
• http://www.theregister.co.uk/2013/03/18/
servers_pets_or_cattle_cern/
• http://www.slideshare.net/randybias/architectures-for-open-
and-scalable-clouds