KVM: Importing an OVA appliance
You may or may not be aware if it, but an OVA file is just a
tar archive containing an .ovf and a .vmdk
files, respectively the VM configuration and disk.
$ ls *.ova
HTAOE.ova
$ tar tf HTAOE.ova
HTAOE.ovf
HTAOE-disk001.vmdk
HTAOE.mf
So, you can simply extract the files:
$ tar xvf HTAOE.ova
And convert to a format appropriate for QEMU/KVM:
List the available formats
$ qemu-img -h | tail -n4
Supported formats: blkdebug blklogwrites blkverify bochs cloop compress copy-before-write copy-on-read dmg file ftp ftps host_cdrom host_device http https luks nbd null-aio null-co nvme parallels preallocate qcow qcow2 qed quorum raw replication ssh throttle vdi vhdx vmdk vpc vvfat
See <https://qemu.org/contribute/report-a-bug> for how to report bugs.
More information on the QEMU project at <https://qemu.org>.
Do the actual conversion (I chose qcow2 here)
$ qemu-img convert -O qcow2 HTAOE.vmdk HTAOE.qcow2
Have a look at the .ovf too, for information on expected
machine configuration, resources (eg. memory and cpu), etc.
After the conversion, simply create a new VM and make it use the newly created disk as the primary disk.