Application/Server dependency mapping

Question

I'm just curious as to whether such as tool exists (free, open source, or commercial but for a reasonable price) before I build it myself.

We're looking for a simple solution to simplify taking web apps online and offline when a server is undergoing maintenance. The idea is that we be able to mark a server as unavailable, and then mark all dependent (direct and indirect) as offline.

Our first proof-of-concept is running, and we created an aspx page that lists various applications that have an App_Offline.html file with a friendly "Down for Maintenance" message in a GridView. In the GridView, each app has a LinkButton that, when clicked, either renames the App_Offline.htm to App_Offline.html or vice-versa to take the app online and offline.

The next step is to set up all of our dependencies. For example, our store locater would be dependent on our web services, which in turn are dependent on our SQL Server. (that's a simple example. We can easily have several layers, or one app dependent on multiple servers, etc.) In this example, if the SQL server goes down, we would need to drill down recursively to find all apps that depend on it, and then turn them off and on by renaming the App_Offline file appropriately.

I realize this will be relatively simple to build, but could be complex to manage. I'm sure we're not the first team to think of this concept, and I'm wondering if there are any open source tools, or if any of you have done something similar and can help us avoid pitfalls.

Edit - Update

I found the category of software I'm looking for. it's called CMDB - (Configuration Management Database), and it's generally more of a Network Admin type tool than a developer tool. I found some open source products in this category, but none written in .NET.

I had considered moving this question to ServerFault.com when I realized I was looking for a netowrk Admin type tool, but since I'm looking for code and a modifiable solution I'll keep the question here.

Answer 1

Pathway Systems sells such a tool for modeling and maintaining such dependency information called Blueprints. It's less overkill than a CMDB, and would probably suite your needs.

Answer 2

Since I've not had any answers, and a week's worth of googling has returned nothing (other than one php open source project that's good, but we don't support php in-house) I'm going to go ahead and write my own.

If it's any good, and my boss does not object, I'll open source it.

If anyone else happens to come up with an answer to this, I will change and accept your answer if it works.