Hi! I'm the author of the blog post that you listed in your article. Glad you found it useful; it surprises me to this day, almost 2 years later, at just how ma

Hi! I'm the author of the blog post that you listed in your article. Glad you found it useful; it surprises me to this day, almost 2 years later, at just how many pageviews it continues to generate. However, I would like to point out that the correct solution to this problem is DNS, as others here have indicated. Couple Route53 with something like Zonify (http://nerds.airbnb.com/easy-aws-inventorying-with-dns/ http://nerds.airbnb.com/easy-aws-inventorying-with-dns/) by the fine folks at AirBnB, and you've got something quite powerful that is diff'able via your normal tools, and can be easily versioned for sanity and safety. Don't let my comments (or the comments of others here) detract from the pretty clever approach that you took. I think it's the fate of every ops/devops to, at some point in their careers, create a host address storage/querying system that contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of DNS without realizing it the first time around.