Formats for Disk Images Another piece of the packaging puzzle is disk image formats. There are many. Each has its own benefits and detriments, but I’m not going to get into those here. Again, this is nowhere near a comprehensive list — just something to help with getting your bearings. I’d like to comment on a couple of the formats that I’ve recently encountered. VDI – VirtualBox’s internal default disk image format is VDI. Nevertheless, this is not what is used by Vagrant boxes. VMDK – One of the most common formats. VMWare’s products use various versions and variations of VMDK disk images. Several versions and variations exist, so it’s very important to understand which one you’re working with and where it can be used.