Distributed Systems Resources
Distributed systems are complicated. Add networking to the mix, and you get traumatic challenges like the CAP theorem and Byzantine fault tolerance. Most of those challenges are unknown to engineers who have to suffer through the vendor marketing presentations, making it hard to determine whether the latest shiny gizmo works outside of PowerPoint.
I started collecting articles describing distributed-system gotchas years ago, wrote numerous blog posts on the topic in the heydays of the SDN Will Save the World lemming run, and organized them into the Distributed Systems Resources page.