Please note: This schedule is for OpenStack Active Technical Contributors participating in the Icehouse Design Summit sessions in Hong Kong. These are working sessions to determine the roadmap of the Icehouse release and make decisions across the project. To see the full OpenStack Summit schedule, including presentations, panels and workshops, go to http://openstacksummitnovember2013.sched.org.
Overview: Work was done during the Havana development cycle to implement "live-snapshot" for virtual machines in Nova. A live-snapshot is basically a more complete snapshot of an instance. In addition to its disk(s), the memory and processor state is also snapshotted. This allows for a quick launch of an instance from the snapshot instead of the regular cold-boot from a snapshot image.
As it turns out, there were some concerns with the hypervisor support for this feature and it did not make it in for the Havana release. This design session is to revive the feature to determine which hypervisors will support it as well as discuss the concerns over the current Libvirt/KVM implementation.
There are also a few other question that should be hashed out for this feature: [a] How are we going to handled attached volumes? How do we handle booting with a different set, or different ordering, of volumes?
[b] How are networks going to be affected? Can a live-snapshot be booted with a different set of networks?
[c] Changes in flavours when a live-snapshot is booted -- We have a live-snapshot of an instance with 512MB of memory, but trying to boot a 1GB instance.
[d] Can CPUID heterogenous clouds be supported? How about cloud composed of different hypervisor versions? Any other host-level issues with live-snapshots.
[e] There also appears to be a need for an in-guest agent to help reconfigure the live-snapshot once its booted. How does nova communicate with the agent? When does the agent know to reconfigure the instance and how does it get the information.
