[libvirt-users] How to use rtc_timeoffset (XL toolkit option) in Libvirt and Xen/libxl hypervisor?

Hello techs, We used XL toolkit for Xen hypervisor for starting Windows hvm VMs and the option rtc_timeoffset worked perfectly with XL. It helped us to set correct Timezone time/offset for Windows HVM VMs from inside virtual_machine xen config. For example: Below option WORKS perfectly with XL toolkit. [root@hw12xen ~]# cat goillltawdlssq.xl.cfg | grep offset rtc_timeoffset = "7200" # +2 hours to UTC time (or +/-3600=+/-1 hour to UTC time) [root@hw12xen ~]# Now we try to migrate all the Windows hvm VMs to using Libvirt and Xen 4.6.6 (or 4.4). But as we see it's impossible to make VMs using correct time/offset set in XML config like below: below Libvirt option DOESN'T WORK as we expect... [root@hw12xen ~]# cat goillltawdlssq.var.xml | grep offset <clock offset='variable' adjustment='7200' /> [root@hw12xen ~]# Can you please explain if there's something we're doing wrong way or it's just a bug like described here: https://bugzilla.redhat.com/show_bug.cgi?id=1212191 ? Thanks in advance.

On 02/16/2018 08:37 AM, Volo M. wrote:
Hello techs,
We used XL toolkit for Xen hypervisor for starting Windows hvm VMs and the option rtc_timeoffset worked perfectly with XL. It helped us to set correct Timezone time/offset for Windows HVM VMs from inside virtual_machine xen config.
For example: Below option WORKS perfectly with XL toolkit. [root@hw12xen ~]# cat goillltawdlssq.xl.cfg | grep offset rtc_timeoffset = "7200" # +2 hours to UTC time (or +/-3600=+/-1 hour to UTC time) [root@hw12xen ~]#
Now we try to migrate all the Windows hvm VMs to using Libvirt and Xen 4.6.6 (or 4.4). But as we see it's impossible to make VMs using correct time/offset set in XML config like below:
below Libvirt option DOESN'T WORK as we expect... [root@hw12xen ~]# cat goillltawdlssq.var.xml | grep offset <clock offset='variable' adjustment='7200' /> [root@hw12xen ~]#
Can you please explain if there's something we're doing wrong way or it's just a bug like described here: https://bugzilla.redhat.com/show_bug.cgi?id=1212191 ?
No, you're not doing anything wrong. And yes, you've hit that bug, although I'd prefer to call it an enhancement request. Xen's rtc_timeoffset setting is currently not supported by the libvirt libxl driver. Regards, Jim

Jim, Thanks a lot for your confirmation. Could you also please explain if the issue can be ever fixed, if it's possible to make some patch to fix it? Is it libvirt-specific bug or Libvirt development team rely on some other developers of libxl code...etc? I'm asking because XL tools works fine and I wonder if XL uses the same libxl libraries , doesn't it? Lastly is the issue is going be fixed in near time? Can you answer my questions and ask for some patch for enhancement request or I should better send a separate email to development team ("libvir-list@redhat.com <https://www.redhat.com/mailman/listinfo/libvir-list>") ? Thanks a lot in advance for your answers... On Fri, Feb 16, 2018 at 8:37 PM, Jim Fehlig <jfehlig@suse.com> wrote:
On 02/16/2018 08:37 AM, Volo M. wrote:
Hello techs,
We used XL toolkit for Xen hypervisor for starting Windows hvm VMs and the option rtc_timeoffset worked perfectly with XL. It helped us to set correct Timezone time/offset for Windows HVM VMs from inside virtual_machine xen config.
For example: Below option WORKS perfectly with XL toolkit. [root@hw12xen ~]# cat goillltawdlssq.xl.cfg | grep offset rtc_timeoffset = "7200" # +2 hours to UTC time (or +/-3600=+/-1 hour to UTC time) [root@hw12xen ~]#
Now we try to migrate all the Windows hvm VMs to using Libvirt and Xen 4.6.6 (or 4.4). But as we see it's impossible to make VMs using correct time/offset set in XML config like below:
below Libvirt option DOESN'T WORK as we expect... [root@hw12xen ~]# cat goillltawdlssq.var.xml | grep offset <clock offset='variable' adjustment='7200' /> [root@hw12xen ~]#
Can you please explain if there's something we're doing wrong way or it's just a bug like described here: https://bugzilla.redhat.com/show_bug.cgi?id=1212191 ?
No, you're not doing anything wrong. And yes, you've hit that bug, although I'd prefer to call it an enhancement request. Xen's rtc_timeoffset setting is currently not supported by the libvirt libxl driver.
Regards, Jim

On 02/19/2018 06:08 AM, Volo M. wrote:
Jim,
Thanks a lot for your confirmation. Could you also please explain if the issue can be ever fixed, if it's possible to make some patch to fix it?
Yes, it can be fixed. I just submitted a patch to the libvirt dev list https://www.redhat.com/archives/libvir-list/2018-February/msg00981.html Please test it and provide feedback if you are able to do so. Thanks! Regards, Jim
participants (2)
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Jim Fehlig
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Volo M.