Univention Bugzilla – Bug 45117
qemu-1.1-2 live migration failes - missing 'kvmclock: Ensure time in migration never goes backward'
Last modified: 2017-08-23 14:59:11 CEST
wrong kvmclock value migrated, leads to VM getting stuck after migration waiting for kvmclock to catch up.
r17637 | Bug #45117 kvmclock: Ensure time in migration never goes Package: qemu-kvm Version: 1.1.2+dfsg-6.54.201708011801 Branch: ucs_4.1-0 Scope: errata4.1-4 r81665 | Bug #45117 kvmclock: Ensure time in migration never goes YAML QA: I have no test myself, but the linked discussion has some hint: start a VM keep it running for some time save-to-disk restore-from-disk From my reading the bug stems from KVM-Clock being stored twice, once inside the guest kernel and once in the KVM Device Migration stream. It the guest view is later than the host view, the VM gets stuck. I will do some testing tomorrow.
Reopen: I fixed a typo in the yaml in r82113 We could not reproduce the problem with the old qemu-kvm version. Updating to the patched version showed no issue with live migration, either. But i found https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786789 There it seems that additional patches are required in addition to the original one used here. Ultimately it was not fixed in jessie. We could apply the additional patches, but i do not the risk of these changes
(In reply to Erik Damrose from comment #2) > Reopen: > I fixed a typo in the yaml in r82113 OK > We could not reproduce the problem with the old qemu-kvm version. Updating > to the patched version showed no issue with live migration, either. But i > found > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786789 > > There it seems that additional patches are required in addition to the > original one used here. Ultimately it was not fixed in jessie. > > We could apply the additional patches, but i do not the risk of these changes r17658 | Bug #45117 kvmclock: add a new function to update Backport of <https://git.qemu.org/gitweb.cgi?p=qemu.git;a=commit;h=0fd7e098db30e302d27920487f0afec33be8982a>, which reverts 1154d84dcc + 317b0a6d8b Package: qemu-kvm Version: 1.1.2+dfsg-6.55.201708152029 Branch: ucs_4.1-0 Scope: errata4.1-4 r82159 | Bug #45117 kvmclock: add a new function to update env->tsc. qemu-kvm.yaml
Still a bit risky, but better than before. In the internal tests, no issues occured while migrating from / to the old and new qemu-kvm version, and between two new versions. OK: patches applied OK: yaml Verified
<http://errata.software-univention.de/ucs/4.1/472.html>