VMware Update Manager is a utility that oversees the installation of updates for existing installations of VMware ESX Server and guest operating systems. Update Manager tracks vulnerabilities within the virtual infrastructure and automatically applies user-defined patches to eliminate those vulnerabilities. The utility is part of the virtualization suite called VMware Infrastructure 3.
VMware Update Manager works in a manner similar to the automatic update feature found in computer operating systems such as Microsoft Windows. Patch data is gathered at user-defined intervals from the VMware repository as well as from Internet-based sites of third-party application vendors. Once the patch data has been collected, it is used to create updates appropriate for the particular system involved. All existing VMware ESX Server hosts and guest operating systems are scanned and compared with the update baseline. A snapshot of each virtual machine's current state is taken to obtain a restore point. All necessary updates are then applied to each virtual machine. If any machine requires a reboot, the action can be delayed by up to 60 minutes to minimize disruption of network operations.