Architecture - December 2013 - Avinash Ramineni, Shekhar Vemuri

1. Recap
• Web services
– SOAP
– Rest
• Security
– Authentication and Authorization
– SSL
• AWS
– EC2,S3,RDS,EBS,ELB

2. Architecture Concepts
PART 1

3. Architecture
• Understanding business goals
• Understanding the constraints
• Set the vision and communicate

4. Architecture
• Software Architecture
• Enterprise Architecture

5. Architecture
• Who are the stakeholders of any Architecture?
• Business
• Technology Leadership
• Developers …

6. Architecture
• Functional vs Non Functional Requirements
• Constraints
• Point in time representation - evolves over time

7. Architecture
• A Conceptual or Logical View of the system
• Implementation View
• Data Flow
• Systems view / Physical view

8. Architecture
• How to communicate?
• UML
• Whiteboard diagrams - boxes and arrows

9. Architecture
• Whiteboard diagrams - boxes and arrows
• Collapse related components
• Have different views
• Keep it abstract - but actionable
• Typically Layered

10. Architecture
• What
• Are we building
• What roles interact with the system
• How does it integrate into the rest of the environment
• Data flows, process flows

11. Architecture
• What
• is the technology stack
• how do interactions between various components
happen?
• What are the lower level technology choices?

12. Architecture
• What
• does the detailed software component architecture
look like?
• How do these components interact with each other
• Fairly low level - developer oriented

13. Architecture
• Component and Functional view
• Interactions - Flows
• Data
• Specific pieces of logic

14. Architecture
• HOW do we do it?
• All up front
• Agile

15. Architecture - Process
• Find the Drivers of the business, Goals, requirements
• What is our strategy to implement this?
• How does the overall vision get implemented?
(roadmap)

16. Architecture - Process
• What are the risks? How do we mitigate them?
• How does the architecture evolve?
• Quality - review - validate

17. Architecture
• A good architecture helps you evolve
• A good design lets you change at a lesser cost
• Abstractions - decoupling help with that
• Reduce tight coupling and hard dependencies

18. Architecture
• Monolithic Applications
• Service Oriented applications

19. N- Tier Architectures

20. Fallacies of Distributed Systems
• The network is reliable
• Latency is zero
• Bandwidth is infinite
• The network is secure
• Topology does not change
• Transport cost is zero
• Network is homogeneous

21. Best Practices
YAGNI
KISS
DRY

22. Best Practices
Continuous Integration / Deployment
Premature Optimization

23. Transactions

24. Distributed Transactions
• Follows 2 Phase Commit protocol
• Very Chatty protocol and does a lot of logging to be able to recover
from any failure scenario.
• Too much overhead to 99.9% of the cases to handle less than 0.1% of
cases
• Increases the chances for deadlocks on the database.
• Lowers the overall performance of the system.
• Bane of scalability. Grinds the entire system to halt by adding
overhead to each and every transaction.

25. Distributed Transactions
• Availability of the Systems goes down.
• XA Configuration is complicated
• Difficult to test.
• Many People tend to believe that using JTA implementation of
transaction manager will take care of a XA transactions
• Many a time people end up using JTA Manager even while
dealing with single resource

26. Asynchronous Architectures
• Event Delivery Guarantees
– Reliability
• At least Once - Duplicate events can be delivered
• At most Once - Some events can be lost
• Once and only Once - Each is delivered Exactly once
– Order of Delivery
• In Order Guaranteed
• In Order not Guaranteed