Re: [libvirt] PATCH: Add domain event "detail" information

On Fri, Nov 14, 2008 at 05:44:29PM +0000, Daniel P. Berrange wrote: > As per our earlier discussion today, this patch expands the callback for > domain events so that it also gets a event type specific 'detail' field. > This is also kept as an int, and we define enumerations for the possible > values associated with each type. [...] Okay, that made the overall callbacks set clearer, ACK > If a event type has no detail, 0 is passed. Actually I would define a detail enum for all event type just to make clear what the value will be and expose how it's intended to be extended if needed. > I don't make use of 'CRASHED' in QEMU driver yet. It might be useful in > Xen though - when a PV guest crashes, Xen stops the domain running, but > leaves it there in a shutoff state, but marked as crashed. > > Now using the C event-test program you can see the effects: > > myDomainEventCallback1 EVENT: Domain F9x86_64(2) Started Booted > myDomainEventCallback2 EVENT: Domain F9x86_64(2) Started Booted > myDomainEventCallback1 EVENT: Domain F9x86_64(-1) Stopped Destroyed > myDomainEventCallback2 EVENT: Domain F9x86_64(-1) Stopped Destroyed > myDomainEventCallback1 EVENT: Domain F9x86_64(3) Started Booted > myDomainEventCallback2 EVENT: Domain F9x86_64(3) Started Booted > myDomainEventCallback1 EVENT: Domain F9x86_64(3) Suspended > myDomainEventCallback2 EVENT: Domain F9x86_64(3) Suspended > myDomainEventCallback1 EVENT: Domain F9x86_64(3) Resumed > myDomainEventCallback2 EVENT: Domain F9x86_64(3) Resumed > myDomainEventCallback1 EVENT: Domain F9x86_64(-1) Stopped Shutdown > myDomainEventCallback2 EVENT: Domain F9x86_64(-1) Stopped Shutdown > > Of the following sequence of actions > > virsh start F9x86_64 > virsh destroy F9x86_64 > virsh start F9x86_64 > virsh suspend F9x86_64 > virsh resume F9x86_64 > virsh shutdown F9x86_64 > > For the last 'shutdown' operation, you'll see the same if you just run > a graceful shutdown inside the guest itself. okay > NB, I've not tested saved/restored because my install of KVM is not new > enough to support that correctly, but I expect it to work without trouble. > Likewise for migration. > > A word about migration... > > - The destination host first gets a STARTED event, with detail MIGRATED > when it starts running > - The source host then gets a STOPPED event with detail MIGRATED when > it completes What about 'live' migration, i.e. events sent when the migration flows begin but the domain is stil running. I don't know if KVM has this but on Xen I would expect to be able to notice this. On the target host that could be indicated by SUSPENDED + VIR_DOMAIN_EVENT_SUSPENDED_MIGRATED because it will consume the memory resource like a suspended domain but no actual CPU cycle (well except for migration itself). On the source host this is a bit harder to indicate, maybe this isn't needed as the resource usage doesn't really change at that point.