When you look at large scale systems from Google, Twitter, eBay, and Amazon, their architecture has evolved into something similar: a set of polyglot microservices.
What does it looks like when you are in the polyglot microservices end state? Randy Shoup, who worked in high level positions at both Google and eBay, has a very interesting talk exploring just that idea: Service Architectures at Scale: Lessons from Google and eBay.
What I really like about Randy's talk is how he is self-consciously trying to immerse you in the experience of something you probably have no experience of: creating, using, perpetuating, and protecting a large scale architecture.
In the Ecosystem of Services section of the talk Randy asks: What does it look like to have a large scale ecosystem of polyglot microservices? In the Operating Services at Scale section he asks: As a service provider what does it feel like to operate such a service? In the Building a Service section he asks: When you are a service owner what does it look like? And in the Service Anti-Patterns section he asks: What can go wrong?
A very powerful approach.
The highlight of the talk for me was the idea of aligning incentives, a consistent theme that crosscuts the entire endeavour. While never explicitly pulled out as a separate strategy, it's the motivation behind why you want small teams to develop small clean services, why a charge back model for internal services is so powerful, how architecture can evolve without an architect, how clean design can evolve from a bottom up process, and how standards can evolve without a central committee.
My takeaway is the deliberate aligning of incentives is how you scale both a large, dynamic organization and a large, dynamic code base. Putting in the right incentives nudges things into happening without explicit control, almost in the same way more work in a distributed system gets done when you remove locks, don't share state, communicate with messages, and parallelize everything.
Let's see how large scale systems are built in the modern era...