In this episode, Our customers depend on them, and our businesses depend on them. Without modern web apps, most businesses would not survive. This is the second in a two part series on the principles for modernizing your enterprise web application.  And then, what is STOSA and how does it help with modern digital applications? Links and More InformationThe following are links mentioned in this episode, and links to related information: Modern Digital Applications Website (https://mdacast.com (https://mdacast.com)) Lee Atchison Articles and Presentations (https://leeatchison.com (https://leeatchison.com)) Architecting for Scale, published by O’Reilly Media (https://architectingforscale.com (https://architectingforscale.com)) STOSA — Single Team Oriented Service Architecture (https://stosa.org (https://stosa.org)) Main Story - Five Principles for Modernizing Your Enterprise Web Applications, p2Modern web applications have a lot riding on them. Our customers depend on them, and our business depends on them. Without modern web applications, many businesses would not survive. Modern web applications must scale to meet our biggest needs without suffering outages or other availability issues. In order to meet and exceed this high bar, we must build, manage, and monitor our applications using modern principles, processes, and procedures. There are five guiding principles that a modern application requires in order to meet these expectations.  In previous episodes, we discussed principle 1, using service-based architectures; principle 2, organizing teams around services; and principle 3, using DevOps processes and procedures. In this episode, we will finish the remaining two principles. Starting with… Principle #4. Use dynamic infrastructures.Customer traffic loads on our applications vary considerably. The upper bound or maximum amount of traffic your application needs to support can never be known accurately. In the past, as application traffic grew, we simply threw additional hardware at the problem. But as traffic variations increase, and customer usage patterns become more complicated. This simple solution is no longer reasonable. Simply adding hardware may be fine to handle expected peaks, but what do you do when an unexpected spike in usage arrives? When I was at Amazon, there was a term that was used. It was called the “Johnny Carson Effect”. It’s origin comes from the day that Johnny Carson died. On that day, there was a huge uptick in demand for any videotape of old episode’s of Johnny Carson’s The Tonight Show. Demand was huge, and given the suddenness of the event, it was all unexpected demand. Now-a-days, the term “going viral” is both a positive and a negative for most businesses. Going viral means huge attention given to you and your business. But it also means huge and unexpected traffic volume. The last thing you want is for your application to fail right at the point when everyone is watching. How can you handle the unexpected surge from such an unexpected event? It is no longer possible to throw large quantities of hardware at an application. You never know how much hardware is enough hardware to handle your possible maximum need. Additionally, when your application is not operating at a high volume, what do you do with the extra hardware? Typically, it’s sitting idle...which is a huge a waste of resources...and even more importantly...a waste of money. Especially if your traffic needs are highly variable or highly spiky, simply adding hardware to handle your peaks is not an effective use of resources. Instead, you must add resources to your applications dynamically, as they are needed and when they are needed. These resources can be applied when your traffic needs are high, and they can be released when they are no longer needed. This is what dynamic infrastructures are all about. The only way to implement a true dynamic infrastructure for an application with a highly variable load is...