I don't like it since the master basically does a curl on each server to get the info, so it doesn't work behind a firewall without tons of issues
(Ok, you do need some knowledge at the parent if you want to raise alerts but you'd need that anyway.)
If you can't easily do that with your existing infrastructure, you should fix that first. I've written about this at http://www.robustperception.io/you-look-good-have-you-lost-m...
Your article is a good one but in my experience, many companies are still many years from being able to implement that kind of database:machine knowledge consistency.
Alerting based on state changes is fragile, it's better to compare against what you expect to see.