MachDB is machine database to catalog of the changing state of your hosts. It consists of a database, an aggregator, an XML spec, and some example information gathering scripts. Along with a Web UI, these form the basis of a system that will allow you to catalog the current and historical state of the hosts in your infrastructure. It has been designed with scale in mind, and the goal is to support 10k hosts. It is being actively developed and is used in production at a few organizations.
Network Inventory Lookup Assistant (NILA) is a combination network inventory database and lookup tool. It is designed to be compact and easily extensible to provide a custom solution for your network. The backend is a Perl CGI script which processes requests and returns output. It uses a SQL server for its storage and retrieval. The frontend is a Perl script which queries the HTTP backend and returns results. It is intended to be simple enough that you can take full advantage of its querying and updating abilities from a console or shell script.