This is a slide deck I have created for a session I did during a Microsoft Executive Meeting in Dublin. It is an excerpt of my SaaS/Multi Tenancy workshop that I do regularly at various conferences.

1. RAINER STROPEK | SOFTWARE ARCHITECTS GMBH
Building multi-tenant
SaaS Applications

2. Goals
• Why should I care?
• What does multi-tenancy + SaaS mean?
• How can the problems be solved?

3. Why should I care?

4. WHY SHOULD I CARE?
Where We Come From
Customer
Dev Team
Close
Relationship
5

5. WHY SHOULD I CARE?
Where Many Of Us Are Today
External/New
Customers
Kunde
Kunde
Customer
Kunde Dev Team
Kunde
Customer
From Cost Center to Shared Service
Center or even Profit Center!
6

6. WHY SHOULD I CARE?
Where We Want To Be
Off-The-Shelf
Product
Customer
Kunde
Kunde Kunde
Kunde Kunde
Kunde Kunde
Kunde Kunde
Kunde Kunde Kunde
Kunde Kunde Kunde
Dev Team Kunde Kunde Kunde
Kunde Kunde
Kunde Kunde Kunde Kunde Kunde
Kunde Kunde
Kunde CustomKunde Kunde Kunde
Kunde Kunde
Customer Custom Kunde Kunde
CustomKunde
Kunde Kunde
Custom
CustomKunde
Customer
7

7. SOLUTION
Catching The Long Tail
The Long Tail
http://www.wired.com/wired/archive/12.10/tail.html, Amazon
Free: The Future of a Radical Price
(Amazon)
8

8. How can
the cloud help?

9. CHALLENGES
Drives Costs Expected
Load
Resources
IT CAPACITY
Real Load Drives Revenue
TIME

10. CHALLANGES
Low
implementation
effort
Complex pricing
model

11. CHALLANGES
Rating/Billing/Payment
– Account/balance infrastructure (debit system
• Web portal for… instead of credit system; example: Skype)
– …registration of new users (has to handle very • E.g. what to do with remaining balance if user cancels
sensitive credit card data  has to be stored safely his account?
and securely, too!) • Fraud detection
– …maintaining customer billing data (e.g. customer
changes address or credit card provider) – Infrastructure for credit checking and fraud
– …cancelling accounts or users detection; examples are…
•
• Infrastructure for rating …credit card checking
• …check of credit ranking for users
– Measure usage
– Rage usage with rates/unit • Support infrastructure for rating/billing/payment
– Additional rating logic will be necessary; examples: issues
• Mechanisms for sales discounts (e.g. • Alternatives
introductory offer)
• Infrastructure for billing • Alternatives for building such a system from scratch
– Creation of invoices (in total for accounting and could be:
itemized bills for checking the correctness) – Buying an existing billing system (expensive; does
– Sending out invoices (electronically with/without only make sense if customer needs such a system in
signature, printed)
other areas, too)
– Storing invoices internally.
– Handle payments with payment partners (e.g.
• Infrastructure for payment; options could be:
payment via phone invoice  difficult because such
– Credit card payments including mechanisms for
handling payment cancellations, invalid credit contracts have to be maintained country by country)
cards (e.g. expired cards), etc. – Use existing SaaS payment solutions (e.g. PayPal;
– Payments via online payment solution like PayPal difficult with pay-per-use)
– Payment with vouchers (e.g. voucher that an end
user received with hardware)

12. Scalability is key, not only
from a technical
perspective but also from
a cost perspective.

13. What does
multi-tenancy + SaaS
mean?

14. CHALLENGES
Multi-Tenancy
Multi-Instance
(ASP)
SaaS Maturity Levels
Kwok, Nguyen, Lam: A Software as a Service with Multi-tenancy
Support for an Electronic Contract Management
Application, IEEE International Conference on e-Business
Engineering, pp. 179-186, 2008
This is where
Multi-Tenancy Windows Azure
shines 15

15. CHALLANGES
This is not the multi-
Cloud ≠ Multi Tenancy tenancy we are talking
about!
Subscription
owned by ISV Cloud
Tenant 1
...
Tenant n
Tenant m
Subscription owned
by customer 16

16. CHALLANGES
Cloud has to enable elastic multi tenancy
Cloud
17

17. How much does it cost
to run your system if
nobody is currently
using it?

18. CHALLANGES
Simple
Implementation
Strategic decision, not a
technical decision
Operational Costs/RGU [€]
Highly optimized
solution
Few large
customers Many small customers
Development Costs [€]
19

19. CHALLENGES
Monitoring
20

20. CHALLENGES
Monitoring
21

21. CHALLENGES
Monitoring
If you want to know more join our upcoming webinar.
22

22. Optimization is
sexy again!

23. CHALLENGES
Source: http://www.flickr.com/photos/mava/2445734571/
One Size Does Not Fit All
24

24. SOLUTION
Extensibility and Customizing
SaaS Configuration Competency Model
Wei Sun, Xin Zhang, Chang Jie Guo, Pei Sun, Hui Su: Software as a Service: Configuration and
Customization Perspectives, in Proceedings of IEEE Congress on Services Part II, 2008
25

25. APPROACH
Metadata Rulez!
Configuration Instead
Of Programming
26

26. Make the API an
integral part of
your product!

27. APPROACH
Model-Driven Architecture
Meta- Base Customer-
Model Model specific Model
Respon- ISV ISV Partner
Partners Customer
sibility
• Different levels of users
– Deverlopers (ISV)
– Consultants (ISV) and partners (External)
– Power users (customer)
– End users (customer)
28

28. Maintaining a multi-
tenant system that is
extensible and
configurable can
be hard.

29. CHALLANGES
Client-Server Model
Program
Version
Clients
Database
Offline
Capabilities
Data Version

30. CHALLANGES
Three-Tier Modell
Program Program
Version Version
Clients
Web Server
Database
Offline Service
Capabilities Version
Data Version

31. CHALLANGES
Multi-Tenancy, Cloud Program
Versions
Data
Versions
Offline Routing-
Capabilities service
Tenant 1
Tenant 2
Clients
Tenant n Web Server
Database
Service
Versions
Program
Versions
Multi-Tenant
Multiple Tenants Load Balancer App-Server Farm Cluster

32. CHALLANGES
Multi-Tenancy, Cloud Program
Versions
Data
Versions
Offline Routing-
Capabilities service
Tenant 1
Tenant 2
Clients
Web Server
Tenant n Database
Service
Manual release
Versions
management is
Program impossible!
Versions
Multi-Tenant
Multiple Tenants Load Balancer App-Server Farm Cluster

33. Conclusion
• Cloud computing enables
people
– There will be more
competition
• It‘s not easy
– Complexity comes from multi-
tenancy + customization
• Have your business plan
ready when moving to a
world of SaaS
– Technology will follow Source: http://www.flickr.com/photos/laurie_pink/2599768757/
34

34. Saves the day.
Thank you!
Questions? You want more?
rainer@software-architects.at