Before embarking on this project I had foolishly assumed I could just create the VM in VirtualBox and then "Export Appliance..." to create a portable OVA. If only it were that simple!
The OVA files that were created by VirtualBox worked fine by other VirtualBox users, but VMware users were getting various levels of success; Fusion wouldn't play nice at all.
I've created this post so that I remember what to do again down the track, and as a side bonus hopefully someone else will benefit or learn from it!
Let me explain some acronyms firstAn OVA file is an Open Virtualisation Appliance. It's essentially a tarball containing an OVF, one or more disk images (usually VMDK files) and a manifest (checksum) file.
The OVF (Open Virtualisation Format) specifies the configuration of the virtual machine. The disk images contain data held by the virtual drives.
Gathering test dataTo get some VMware test data I dragged my old HP N54L out of the cupboard and installed ESXi 6.5 on it. The disk performance was horrendously slow until I disabled the problematic AHCI driver as per this blog.
After creating a few OVA files from ESXi, my testing concluded that VirtualBox happily accepted a VMware OVA but VMware had a hard time working with a VirtualBox OVA.
My VirtualBox solutionI decided to keep things simple and use ESXi to generate the initial OVA. I chose to target VMware 4 to keep it compatible with pretty much everything. After this step ESXi was no longer required.
I then unpacked said OVA, prepared the replacement disk image with VirtualBox and rolled my own OVA using a few commands.
The initial OVA contained the following:
$ tar xvf covfefe.ova
To prepare the replacement disk-0.vmdk file, I ran through the steps in my earlier blog post and converted from VDI to VMDK with clonemedium (also mentioned in the same post).
After replacing the VMDK file, I edited the size entry in the OVF to reflect the new file:
<File ovf:href="disk-0.vmdk" ovf:id="file1" ovf:size="464093696"/>
Once I finished editing the OVF I had to create the correct checksums to use in the manifest file:
$ shasum covfefe.ovf disk-0.vmdk
After the changes my manifest file looked like this:
$ cat covfefe.mf
SHA1 (covfefe.ovf)= 249eef04df64f45a185e809e18fb285cadfcd6f0
SHA1 (disk-0.vmdk)= ae1718beb7d5eb7dfb5158718b0eceda812512a2
I then reassembled the OVA file:
$ tar cf covfefe.ova covfefe.ovf covfefe.mf disk-0.vmdk
Just as a test I also did the assembly using OVF Tool as it did some extra checks while assembling:
$ /Applications/VMware\ OVF\ Tool/ovftool covfefe.ovf covfefe.ova
The OVA has worked flawlessly on everything I've tested it on so far which is VirtualBox 5.1.22, VMware ESXi 6.5, Fusion 8.5.8 and Player 6.0.1.