Introduction to VMware's Virtual Disk Development Kit (VDDK)

One of the conditions of moving to vSphere for a customer of mine was the ability to quickly modify a set of files in a virtual disk after cloning it, but before deploying it as a virtual machine.  Fortunately for him (and myself) VMware has a tool that will do just that and more.  Although not widely known, VMware released the Virtual Disk Development Kit (VDDK) as a set of Open APIs a couple of years ago for modifying and manipulating virtual disk files (or vmdk’s).  The main purpose of the VDDK was for partners and customers to write their own applications to integrate with VMware storage using the included set of C function calls and executables.

Most of these partners used the VDDK to develop slick backup applications that made the VI Admins life’s a lot easier and there was no longer a need for a backup proxy server in most cases (think VCB).  The VDDK, along with the vSphere SDK make up the vStorage APIs for Data Protection enabling these backup solutions to function.  The VDDK is both a Windows and Linux based set of APIs that can interact with pretty much any of VMware’s hypervisors and their associated disk files.

I’m not a programmer and don’t intend to focus on the APIs.  In the posts that follow, I’ll walk you though the two executables included with the VDDK, vmware-mount and vmware-vdiskmanager and how they can best be used.  Since both tools are CLI based, there are third party tools that take advantage of the VDDK for all you fans of the GUI and we’ll take a look at those as well.

Documentation and Download

First and foremost, how do you get the VDDK and where is the documentation?  All of the documentation is here along with the download link.  Since you will need a VMware Store account to access the download, I cannot provide a direct link to it, just click on the Download link at the top.  There are separate PDF files for the Disk Mount User’s Guide, the Virtual Disk Manager User’s Guide, as well as Designing Backup Solutions for vSphere and the Virtual Disk Programmers Guide.