A CMDB, or configuration management database, records and tracks configuration items (CI) that are part of an IT department's information system. A CMDB describes CIs based on technical, ownership and relationship attributes. A CMDB helps keep metadata for IT department up to date. There are many open source CMDB tools that help you build your configuration management database.
The ECDB Toolset
The ECDB Toolset is a LAMP build based on Ubuntu, and it consists of Nmap2Mysql, Nagios, Oreon, The Owl Document Management System, Post Nuke Calendar, OCS Inventory System and PHPBB2 chat.
Nmap2Mysql will scan your network for data to populate your CMDB.
Zenoss is a systems monitoring system which helps you analyse your data.
Project Open is enterprise project management software that integrates CRM, project management, sales and invoicing.