Cloud architect Andrija Panić has developed an alternative to VMware’s Virtual Disk Development Kit. Following the earlier release of V2K Migrate, OpenVDDK serves as a drop-in replacement for the VDDK, which is now very limited in availability. This removes a roadblock imposed by Broadcom on VMware migrations.
Panić states that VM migrations are already using OpenVDDK. He told The Register that he didn’t think it was fair for a Broadcom download page to determine whether user data could be protected and migrated. The project specifically replaces libvixDiskLib.so.8.0.3, but the code is in no way identical. The tool is written in Go with a C layer to expose the same interface, library name, and symbol versions. The code is licensed under an Apache license. Panić is also a committer and PMC member of Apache CloudStack, which is considered one of the many KVM-based VMware alternatives.
Drop-in replacement without VMware code
Although VDDK was never intended to simplify VMware migrations, that has been one of the uses for the backup tool. Popular solutions such as Azure Migrate, Nutanix Move, and Red Hat’s Forklift use or have used VDDK. Since Broadcom blocked downloads, these providers of VMware alternatives have had to adapt their tools. Broadcom partners still have access to VDDK.
There is one significant limitation compared to the original VMware tool. OpenVDDK is read-only and is therefore not a complete like-for-like replacement for VDDK in all applications. For migrations, however, this functionality is sufficient.
The tool has already been tested on vSphere 6.7 U3, 7.0.3, 8.0.3, and 9.1.1. The Register reports that successful tests have already been conducted using Forklift, MTV on OpenShift, a Proxmox VE pipeline, and proprietary nbdkit tools. A German cloud provider is said to have already migrated a large file server using this tooling.
Other approaches
OpenVDDK is one of many ways to migrate away from VMware as smoothly as possible. For example, Nutanix Move has used DirectPath since version 6.3.3, which reads VM disks directly from ESXi to AHV. OpenNebula, meanwhile, offers OneSwap, which boasts a 96 percent success rate. This tool also does not require VDDK and works via virt-v2v and qemu-img. For VMs running on vSAN, however, VDDK remains necessary.
See also: VMware restricts VDDK for migrations