UMDS

Most vSphere admins are more than comfortable with using Update Manager to download patches and update their environment, but few that I talk to actually know a huge amount about the Update Mangaer Download Service (UMDS). UMDS is tool you can install to download patches (and third party VIBs - I’ll get to that) for Update Manager and it’s useful for environments that don’t have access to the internet, or air-gapped, and also for environments with multiple vCenter Servers where you don’t necessarily want to download the same patch on every server. You can control which patches you download (for example, limiting to ESXi 6.7+ only) and you can add third party Vendor repositories (e.g. Dell or HPE).

The vSphere UMDS provides a way to download patches for VMware servers that have an air-gap, or for some reason aren’t allowed to go out to the internet themselves – in my case a security policy prevented a DMZ vCenter Server from connecting to the internet directly. The solution is to use UMDS to download the updates to a 2nd server that was hosted in the DMZ and then update the vCenter Server from there. It also can save on bandwidth if you’re running multiple vCenter Servers, which again was the case (though bandwidth isn’t really a constraint).