On Mon, Nov 05, 2012 at 04:02:28PM +0100, Peter Krempa wrote: > When the daemon is starting it autostarts all guests marked as > autostartable. This is not an ideal solution for autostarting if there's > a lot of domains configured so. After autostarting all right away the > guests start competing for disk I/O and the boot is prolonged > unnecessarily. > > This patch adds a config option to disable autostarting to leave it on > user scripts that may use mechanisms to reduce load of the host by > limiting the number of guests started in parallel. > > Unfortunately, there's no simple way we could do this in libvirt. The > problem is how to detect that the guest has finished booting as it's > mostly a black box for libvirt. There area few options: > > 1) Wait until I/O load of the guest drops. > - This is insufficient on guests that do heavy I/O all the time. > > 2) Let the guest tell us. > - Not every OS has the ability to have a guest agent. > > 3) Wait for certain amount of time. > - Very limited amount of control on diverse guests. > > With this functionality, the user may write his own script that load > balances the autostart in a sane way with accordance to his > infrastructure (Query agents, check I/O, use configurable timeouts) > while stil being able to mark the domains as autostartable with all the > benefits (virsh list --all --autostart). > --- > We could also add an example script based on parts of libvirt-guests to show > how to use this. > --- > src/qemu/qemu.conf | 7 +++++++ > src/qemu/qemu_conf.c | 4 ++++ > src/qemu/qemu_conf.h | 2 ++ > src/qemu/qemu_driver.c | 5 ++++- > 4 files changed, 17 insertions(+), 1 deletion(-) I sort wonder whether it is better to expose this as a command line argument rather than a config option. It would make life much easier for people who want to have autostart running most of the time, but occassionally want to start libvirtd without it. 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