POC

With a complete statement and several options already defined, we can proceed to provide a POC based on one of the possible routes.

A POC is the process of demonstrating an idea or method, in our case a solution, with the aim of verifying a given functionality. Additionally, it provides a broad overview of how the solution will behave within an environment, allowing further testing to be able to fine-tune for specific workloads and use cases.

Any POC will have its advantages and disadvantages, but the main focus is for customers and architects to explore the different concepts of the solution of an actual working environment. It is important to note that you, as an architect, have a heavy influence in which POC will be used as a final solution, but the customer is the one who chooses which constraints and advantages suit their business better.

With the example of choosing an NGINX as a load balancer to provide high availability and performance improvements to Apache web servers hosting the application files, we can implement a working solution with scaled-down resources. Instead of deploying four nodes for the final solution, we can deploy just two to demonstrate the load-balancing features as well as provide a practical demonstration of high availability by purposely bringing one of them down.

Here's a diagram describing the previous example:

This does not require the full four-node cluster that was envisioned during the design phase, as we're not testing the full performance of the entire solution. For performance or load testing, this can be done by having less concurrent users provide a close to actual workload for the application. While having fewer users will never provide exact performance numbers for the full implementation, it delivers a good baseline with data that can later be extrapolated to provide an approximation of what the actual performance will be.

As an example for performance testing, instead of having 2,000 users load the application, we can have a quarter of the userbase and half of the resources. This will considerably decrease the amount of resources needed, while providing enough data to be able to analyze the performance of the final solution at the same time.

Also, in the information gathering stage, a document that has the different POC documented is a good idea, as it can serve as a starting point if the customer wants to construct a similar solution in the future.