Without committing to an entire book, perhaps more detail on load-balancing and proxies?

https://blog.envoyproxy.io/introduction-to-modern-network-lo...

I posted this above in reply to someone else asking the same question:

> Perhaps "Web Scalability for Startup Engineers" by Artur Ejsmont. But I admit I have't read it yet -- I however felt the same as you and started exploring for more resources after coming across this thread.