In this chapter, you learned about various design patterns by applying the techniques from Chapter 3, Attributes of the Solution Architecture, and Chapter 4, Principles of Solution Architecture Design. First, you built the architecture design foundation from a multilayer architecture with a reference architecture from three-tier web application architecture. You learned how to design a multi-tenant architecture on top of a three-tier architecture, which can provide a SaaS kind of offering. You learned how to isolate multi-tenant architecture at the database label, schema level, and table level as per customer and organization need.

User state management is very critical for complex applications such as finance, e-commerce, travel booking, and more. You learned about the difference between stateful and stateless applications and their benefits. You also learned how to create a stateless application with a persistent layer of the database for session management. You learned about the two most popular SOA patterns, SOAP-based and RESTful-based patterns, along with their benefits. You looked at a reference architecture of an e-commerce website based on SOA and learned how to apply the principle of loose coupling and scaling.

You learned about serverless architecture and how to design a secure survey delivery architecture that is entirely serverless. You also learned about microservice architecture using the example of a serverless real-time voting application, which builds on the microservice pattern. For more loose coupling designs, you learned about queuing chain and job observer patterns, which provide loosely coupled pipelines to process messages in parallel. You learned about the pub/sub and event stream models to design event-driven architecture. 

It's not possible to achieve your desired performance without applying caching. You learned about various cache patterns to apply to caches at the client side, content distribution, web layer, application layer, and database layer. You learned architecture patterns to handle failure such as a circuit breaker to handle the downstream service failure scenario and bulkhead pattern to handle complete service failure. You learned about floating IP patterns to change servers without changing their address in failure situations to minimize downtime.

You learned about the various technique of handing data in an application and how to make sure your database is highly available to serve your application. Finally, you learned about various architecture anti-patterns and how to replace them using best practices.

While, in this chapter, you learned about various architecture patterns, in the next chapter, you will learn about architecture design principles for performance optimization. Additionally, you will deep dive into technology selection in the area of computing, storage, databases, and networking, which can help to improve your application's performance.