VMware has discontinued public downloads of its Virtual Disk Development Kit (VDDK). The SDK is used, among other things, by tools that migrate virtual machines to competing platforms. VMware states that VDDK was never licensed for that purpose.
This was reported by The Register. The VDDK includes libraries, utilities, and APIs that let software access VMware virtual disks. The technology was originally intended for applications related to backup, recovery, and cloning virtual machines. In practice, however, the SDK has also proven suitable for extracting VMs from a VMware environment.
Several competitors are using it. Nutanix uses VDDK within its migration tool Move, while Red Hat recommends the technology for migrations to its virtualization environment. Tools for migrating VMware workloads to KVM can also use VDDK as a transport method.
Now available only through partners
VMware has since removed the VDDK download pages. According to The Register, this happened without prior notice. The SDK is not disappearing entirely, however. Selected Technology Alliance Partners (TAPs) retain access to VDDK for applications that, according to VMware, fall within the license terms.
VMware draws a clear line here. The company states that VDDK has always been intended for backup and recovery. According to VMware, migration to other virtualization platforms is not a licensed use.
The company also emphasizes that access to VDDK is not part of a VMware license. It is a separate SDK with its own license terms. According to VMware, customers who need VDDK for backup and recovery can use solutions from approved partners.
Implications for existing migrations
The decision may pose particular problems for organizations and service providers that already use VDDK in migration processes. Integrator ShapeBlue points out that documentation for Apache CloudStack, among other things, still referenced the now-defunct download page.
Major software vendors partnered with VMware can still obtain the SDK. Smaller migration specialists, open-source projects, and companies that want to migrate workloads on their own do not automatically have that option.
Alternative methods now exist for migrating VMware VMs to other environments without VDDK. Removing the public download does not make such a transition impossible, but it can disrupt or complicate existing migration procedures.
Licensing policy under scrutiny
This move comes at a time when VMware’s licensing policy has been a frequent topic of debate since its acquisition by Broadcom. Some customers are exploring alternatives or scaling back their use of VMware technology.
The Register notes that VDDK was publicly available for years and that VMware must have known that other vendors were using the SDK for migrations. The publication therefore views the discontinuation of downloads as a possible attempt to make switching to competing platforms less straightforward.
However, the impact of this move appears to be limited. Actually moving VMs is only one part of a migration. Network configuration, storage, security, and reconfiguring the entire virtualization environment typically account for a much larger portion of the work.