OpenStack Compute (nova)

Time synchronization with qemu guest agent when resuming VM

Registered by Taku Izumi

VM's clock always loses time when resuming from paused state, because guest OS can't aware pausing/resuming so its clock continues from the moment it was suspended. Time synchronization should be automated when resuming VM.

Fortunately libvirt 1.2.5 added a virDomainSetTime API to trigger the guest agent to re-read the hardware clock and adjust software time from that. To impelment this feature in KVM instances, nova-compute libvirt driver should invoke virDomaiinSetTime API to adjust guest time with hardware clock when resuming VM.

This feature will be libvirt driver specific, and requires qemu guest agent installed in the instances
and 'hw_qemu_guest_agent=yes' property in the image metadata.

Blueprint information

Status:
Not started
Approver:
None
Priority:
Undefined
Drafter:
Taku Izumi
Direction:
Needs approval
Assignee:
Taku Izumi
Definition:
New
Series goal:
None
Implementation:
Unknown
Milestone target:
None

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Gerrit topic: https://review.openstack.org/#q,topic:bp/time-sync-with-qemu-guest-agent-when-resuming-vm,n,z

Addressed by: https://review.openstack.org/347625
    libvirt: Time synchronization with qemu guest agent when resuming VM

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