On Wed, Aug 4, 2010 at 6:03 PM, Ewan Mellor <[email protected]> wrote: > On Wed, Aug 04, 2010 at 09:52:28PM +0100, Jay Pipes wrote: > >> > This is not how they're being used in the code though. In particular, when >> > we get an exception during spawn we set the state to SHUTDOWN (in libvirt >> > semantics, "being shut down") and when destroying a VM, we wait for it to >> > transition to SHUTDOWN, rather than SHUTOFF. >> >> Yes, that is indeed inconsistent. In the case of the exception during >> spawn, what would be the state you suggest transitioning to? Perhaps >> CRASHED? > > In XenAPI, we have three axes, if that's the right term: > > The actual state of the VM, as observed by the virtualization layer: Running, > Halted, Suspended, Paused. > > Tasks that are in progress: start, clean reboot, or clean shutdown, for > example. > > Reasons for the last shutdown: it crashed, it shut down by itself, it was > asked to shut down by the platform, it was hard powered off by the platform. > > The power states are definitive: a VM is either running, or it isn't. > > The tasks are transitory, and may trigger a power state transition, e.g. a > clean shutdown task will cause a transition from Running to Halted once it is > complete (or it will fail, and the VM will stay in state Running). > > The shutdown reasons are there to record the necessary information without > exploding the state space. A VM that has crashed at the end of the day is > still Halted. The fact that it crashed is useful information, but ultimately > its now indistinguishable from a VM that was powered off -- they are both > merely Halted.
I would fully support using the Xen API's tuple of power states and reasons for last shutdown as a replacement for the current libvirt-specific stuff. Seems quite reasonable and much more definitive than libvirt's states. -jay _______________________________________________ Mailing list: https://launchpad.net/~nova Post to : [email protected] Unsubscribe : https://launchpad.net/~nova More help : https://help.launchpad.net/ListHelp
