Re: [pbs-devel] Templates starting on backup

[Graeme Seaton <lists@graemes.com>]

Hi,

In one case CPU type/Numa/hugepages.  In others vmbr's.

Regards,

Graeme

On 05/10/2020 14:42, Thomas Lamprecht wrote:
> Hi,
>
> On 05.10.20 14:15, Graeme Seaton wrote:
>> I store my templates on a common host and move to deployment host as necessary.  Unfortunately, when backup up the process tries to start the template and then fails if there is a difference in the hardware configuration between the current host and it's definition.
>>
>> Given that templates (if I understand correctly) are not run directly shouldn't the backup just work with the images since there won't be any dirty blocks to be detected?
>>
> Yes, they have no dirty bitmap by definition, but we start them up so that
> we can re-use our QEMU backup integration for PBS. The VM is not started for
> real, just a QEMU process is running - this shows up in the webinterface
> (because it's a cheap check) - but the backup lock symbol should avoid
> confusions.
>
> Re-using the QEMU built in block drivers to access the templates disks allows
> to avoid duplicating quite some logic and functionality, and solves a few
> edge cases "for free". That's the main reason we use it here.
>
>
> What HW differences are talking here?
>
> cheers,
> Thomas
>
>