[openstack-dev] [nova] how does UEFI booting of VM manage per-instance copies of OVMF_VARS.fd ?

Jay Pipes jaypipes at gmail.com
Thu Sep 28 16:53:16 UTC 2017

On 09/27/2017 09:09 AM, Waines, Greg wrote:
> Hey there ... a question about UEFI booting of VMs.
> i.e.
> glance image-create --file cloud-2730. qcow --disk-format qcow2 
> --container-format bare --property “hw-firmware-type=uefi” --name 
> clear-linux-image
> in order to specify that you want to use UEFI (instead of BIOS) when 
> booting VMs with this image
> i.e.    /usr/share/OVMF/OVMF_CODE.fd
>            /usr/share/OVMF/OVMF_VARS.fd
> and I believe you can boot into the UEFI Shell, i.e. to change UEFI 
> variables in NVRAM (OVMF_VARS.fd) by
> booting VM with /usr/share/OVMF/UefiShell.iso in cd ...
> e.g. to changes Secure Boot keys or something like that.
> ·how does NOVA manage a unique instance of OVMF_VARS.fd for each instance ?
> oi believe OVMF_VARS.fd is suppose to just be used as a template, and
> is supposed to be copied to make a unique instance for each VM that UEFI 
> boots
> ohow does NOVA manage this ?
> §e.g. is the unique instance of OVMF_VARS.fd created in
>           /etc/nova/instances/<UUID>/  ?
> o... and does this get migrated to another compute if VM is migrated ?

Hi Greg,

I think the following part of the code essentially sums up what you're 
experiencing [1]:

LOG.warning("uefi support is without some kind of "
             "functional testing and therefore "
             "considered experimental.")


 From what I can tell, the bootloader is hardcoded to 
"/usr/share/OVMF/OVMF_CODE.fd" for x86_64:



and I see no way to change it via a configuration variable...

Yet another half-baked, completely untested "feature" added to Nova. :(


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