VMware vSphere Update Manager Download Service (UMDS) is an optional module of Update Manager. UMDS downloads upgrades for virtual appliances, patch metadata, patch binaries, and notifications that would not otherwise be available to the Update Manager server.
For security reasons and deployment restrictions, vSphere, including Update Manager, might be installed in a secured network that is disconnected from other local networks and the Internet. Update Manager requires access to patch information to function properly. In such an environment, you can install UMDS on a computer that has Internet access to download upgrades, patch binaries, and patch metadata, and then export the downloads to a portable media drive so that they become accessible to the Update Manager server.
In a deployment where the machine on which Update Manager is installed has no Internet access, but is connected to a server that has Internet access, you can automate the export process and transfer files from UMDS to the Update Manager server by using a Web server on the machine on which UMDS is installed.
UMDS 5.5 supports patch recalls and notifications. A patch is recalled if the released patch has problems or potential issues. After you download patch data and notifications with UMDS, and export the downloads so that they become available to the Update Manager server, Update Manager deletes the recalled patches and displays the notifications on the Update Manager Notifications tab. For more information about patch recalls and notifications, see Configuring and Viewing Notifications.