Re: [libvirt] How to avoid the disk still persistent after no persistent hotplug and with restarting libvirtd then.

On 08/19/2011 08:17 AM, Osier Yang wrote: > Libvirt loads the domain conf from the status file > (/var/run/libvirt/qemu/$dom.xml) > if the domain is running, the problem if one restart libvirtd just after > some changing on the domain conf, and then destroy/start the guest. > libvirt will never known what the original domain conf is then. > (vm->newdef is NULL at this moment, generally libvirt restore the domain > conf > to the original conf (vm->newDef) when destroying and shutdown). Sounds to me like this is a bug in libvirtd reloading. For a running persistent guest, libvirt should be looking in two files: both the running state (/var/run/libvirt/qemu/$dom.xml) and the next-boot state (/etc/lib/libvirt/qemu/$dom.xml); and if they differ, then assign vm->newDef to the persistent definition.

In other words, the bug is that vm->newdef was NULL after libvirtd restart.

> The solution in my mind is to add some attribute to the status XML, such > as "live_updated=1", and do the checking when loading the domain conf > from status XML: Shouldn't need any XML changes; rather, libvirtd just needs to be taught to properly reconstruct its state from multiple files, instead of assuming that the first file that worked was all the state it needed. > For a transient domain, we still have no way to get the original domain > conf, > that means one will still be surprised when seeing the the disk is still > there. For a transient domain, it is already forbidden to request a persistent change. So you can't get into this situation in the first place unless you have a persistent domain.