I’ve had to do this a couple of times lately so thought I’d finally write down what I actually did for future reference. Kudos goes to Berk at Tekbyte.net.
Was a pretty simple procedure in the end.
An ova file is just a VMWare ovf directory tarred up to be installed. So the first stage of the conversion is to untar the file.
tar -xvf <filename>.ova
This will extract several files into the current directory. The one we are interested in is the .vmdk file. This is a VMWare virtual disk file. This can then be converted using the following command:
qemu-image convert <vmFileName>.vmdk <newfilename>.qcow2 -O qcow2
That’s about it. If they aren’t required then all the files with the exception of your shiney new qcow2 can be deleted.