[libvirt] libxl and non-absolute paths

[Stefan Bader]

On 16.02.2015 10:18, Martin Kletzander wrote:
> On Fri, Feb 13, 2015 at 03:20:07PM +0100, Stefan Bader wrote:
>> Just recently we moved to libvirt 1.2.12 for the next release. Which brought up
>> a few problems when working with configs which we and Debian used to have.
>>
>> A mild complaint towards the xml validation: it would be really nice of that
>> would be a bit more specific about what exactly it complains. It took me a while
>> to realize that "Extra element os in interleave" was trying to tell me
>> that the string of the loader element within the os section was not an absolute
>> path.
>>
>> The issue here is that with libxl, I think the goal was to rather allow the
>> library to select the path prefix (like for pygrub where the full path got
>> removed recently). But now the xml validation disagrees.
>>
>> This would go for bootloader for xenpv and loader (within os) for xenfv. And for
>> emulator in the device section. Though for that things are a bit more
>> complicated. The libxl driver now calls that with the help option and decides
>> from the output whether this is the "traditional" xen forked qemu or the
>> upstream qemu binary. Then it selects the device model depending on that outcome.
>> Not sure whether the libxl driver could query libxl for the path prefix. Right
>> now the most straight forward way seems to move back to a full path for the
>> emulator. At least now, by using the standard qemu binary for everything, we got
>> a predictable path that does not change with Xen versions. So its possible to
>> force migrate over to put /usr/bin/qemu-system-i386 there.
>>
>> But for loader and bootloader, do you think it reasonable to change the
>> templates from absFilePath to filePath?
>>
> 
> Maybe stupid question here... How does the string with the prefix look
> like then?  Is it something like <bootloader>pygrub:/path/to/loader ?

No, sorry I should probably have added that: in both cases there is only the
binary name in the config and libxl extends things internally.

So <bootloader>pygrub</bootloader> and <loader>hvmloader</loader>.

-Stefan

> 
>> -Stefan
>>
>> --- libvirt-1.2.12.orig/docs/schemas/domaincommon.rng   2015-01-23 12:46:24.0000
>> +++ libvirt-1.2.12/docs/schemas/domaincommon.rng        2015-02-13 10:00:43.1616
>> @@ -258,7 +258,7 @@
>>                 </choice>
>>               </attribute>
>>             </optional>
>> -            <ref name="absFilePath"/>
>> +            <ref name="filePath"/>
>>           </element>
>>         </optional>
>>         <optional>
>> @@ -1060,7 +1060,7 @@
>>       <optional>
>>         <element name="bootloader">
>>           <choice>
>> -            <ref name="absFilePath"/>
>> +            <ref name="filePath"/>
>>             <empty/>
>>           </choice>
>>         </element>
>>
> 
> 
> 
>> -- 
>> libvir-list mailing list
>> libvir-list at redhat.com
>> https://www.redhat.com/mailman/listinfo/libvir-list


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20150216/a9b1d562/attachment-0001.sig>