It's totally possible, but in my experience, the filesizes of qcow2 files tend to be quite large, which impacts our mirror providers. They can be compressed, but the trade-off for that is that there is a performance hit when the compressed data is decompressed on the fly. To avoid that, you can manually decompress the image first. But if you're going to do that, then there isn't really any advantage for us to distribute a qcow2 image. I.e. you may as well just convert a OVA or VMDK image!

Also we haven't had that much request for it so it's never been much of a priority.

So we're potentially open to it, but would need to be convinced of the benefit before we do that.

In the meantime, (as you are possibly already aware) you can covert a VMDK image to qcow2 if you wish.

If using our VMDK build (e.g. turnkey-core-16.1-buster-amd64-vmdk.zip) then you'll need unzip first, then convert:

unzip turnkey-core-16.1-buster-amd64-vmdk.zip
qemu-img convert -O qcow2 turnkey-core-16.1-buster-amd64/turnkey-core-16.1-buster-amd64.vmdk turnkey-core-16.1-buster-amd64.qcow2

Or, starting with the OVA build (turnkey-core-16.1-buster-amd64.ova), untar then convert:

tar xf turnkey-core-16.1-buster-amd64.ova
qemu-img convert -O qcow2 turnkey-core-16.1-buster-amd64-disk1.vmdk turnkey-core-16.1-buster-amd64.qcow2