[pbs-devel] Templates starting on backup

[Thomas Lamprecht]

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