On Tue, Apr 15, 2014 at 05:31:17PM +0300, Laine Stump wrote: > On 04/15/2014 03:27 PM, John Ferlan wrote: > > > > On 04/10/2014 09:19 AM, Laine Stump wrote: > >> This eliminates problems with upgrading from older libvirt that stores > >> network status in /var/lib/libvirt/network to newer libvirt that > >> stores it in /var/run/libvirt/network, by also reading any status > >> files from the old location, saving them to the new location, and > >> removing them from the old location. > >> > >> This will not help those trying to downgrade, but in practice this > >> will only be problematic in two cases > >> > >> 1) If there are networks with network-wide bandwidth limits configured > >> and in use by a guest during a downgrade to "old" libvirt. In this > >> case, the class ID's used for that network's tc rules, as well as > >> the currently in-use bandwidth "floor" will be forgotten > >> > >> 2) If someone does this: 1) upgrade, 2) downgrade, 3) modify running > >> state of network (e.g. add a static dhcp host, etc), 4) upgrade. In > >> this case, the modifications to the running network will be lost > >> (but not any persistent changes to the network's config). > >> > >> I have an idea of how to make these cases work properly as well > >> (involving symlinks in /var/lib pointing to /var/run) but want to > >> avoid keeping such an ugly legacy around (forever) unlesss others > >> think it is absolutely necessary to support flawless downgrades across > >> this line *while remaining in service*. > > I would have to believe/think the downgrade issue has happened before > > with some other change to config or status file locations. > > > Thinking about it, there was one similar situation - when sessionmode > libvirtd switched from using gnome2 config directories to gnome3. I > don't recall if anything special was done in that case, or if it was > just considered not important because ... session mode. We migrated the locations - see migrateProfile() in daemon/libvirtd.c Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list