It's nice to see a more detailed technical explanation of this. I've used the story of Knight Capital is part of my pitching for my own startup, which addresses (among other things) consistency between server configurations.

This isn't just a deployment problem. It's a monitoring problem. What mechanism did they have to tell if the servers were out of sync? Manual review is the recommended approach. Seriously? You're going to trust human eyeballs for the thousands of different configuration parameters?

Have computers do what computers do well - like compare complex system configurations to find things that are out of sync. Have humans do what humans do well - deciding what to do when things don't look right.