[libvirt-users] Configuring default network/storage for qemu:///session
Hi libvirt-user, If I run (as a normal user): virsh -c qemu:///session net-list --all virsh -c qemu:///session pool-list --all I see a default network and a default pool. And indeed, these appear in the persistent configuration. It seems these are created the first time libvirtd is (auto)started in qemu:///session mode. Is it possible to configure the attributes of the default network and default pool that are created? This is to provide configuration for newly created users. Normally I would just put some default configuration in /etc/skel. But it seems that a UUID element needs to be present in the network and pool configuration. And so for my configuration to be correct I either need to wrap add some special sauce to adduser that generates several UUIDs and puts them in the configuration, or just generate the UUIDs in advance and let them be copied to all users. Currently I'm taking the second option, so all users have the same UUID for their default network and pool. I don't know if that might hurt me in the future, but it certainly seems distasteful. Thanks!
On Thu, Mar 03, 2016 at 10:20:41AM -0500, catern@catern.com wrote:
Hi libvirt-user,
If I run (as a normal user):
virsh -c qemu:///session net-list --all virsh -c qemu:///session pool-list --all
I see a default network and a default pool. And indeed, these appear in the persistent configuration. It seems these are created the first time libvirtd is (auto)started in qemu:///session mode. Is it possible to configure the attributes of the default network and default pool that are created?
This is to provide configuration for newly created users. Normally I would just put some default configuration in /etc/skel.
There's nothing in libvirt which auto-creates such resources by default. IIRC, it is probably virt-manager and/or GNOME Boxes applications which are creating them. 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 :|
"Daniel P. Berrange" <berrange@redhat.com> writes:
There's nothing in libvirt which auto-creates such resources by default.
IIRC, it is probably virt-manager and/or GNOME Boxes applications which are creating them.
Ah, in this case it's virt-install, quite right. My mistake. Still, then, what would be best way to have some initial configuration for qemu:///session? The configuration in question is two networks, to use bridges that are set up on this system to be usable unprivileged with qemu-bridge-helper. Since I can't control, and don't want to try to control, what libvirt-consuming applications are run by the user, that method is out. So is there some way I can put the configuration in /etc/skel and have the UUID be autogenerated? Or am I going to have to write a script to be run on user-creation, to generate new UUIDs for each new user? Or does it not matter that all the network resources under the different users have the same UUIDs? Thanks.
On 03/03/2016 11:03 AM, catern@catern.com wrote:
"Daniel P. Berrange" <berrange@redhat.com> writes:
There's nothing in libvirt which auto-creates such resources by default.
IIRC, it is probably virt-manager and/or GNOME Boxes applications which are creating them. Ah, in this case it's virt-install, quite right. My mistake.
Nope. virt-install doesn't create any libvirt network. It only uses existing networks. Of course in session mode libvirt the type of networks that are usable are very limited. There is only one, as a matter of fact - the "unmanaged" network (one which simply points to an existing bridge on the host), e.g.: <network> <name>test</name> <bridge name='virbr0'/> <forward mode='bridge'/> </network> So you have a network like this automatically added? That doesn't happen when I run virt-install. Perhaps, as Daniel suggested, it was gnome-boxes that did this (virt-manager may add a default storage pool, but I'm pretty sure it wouldn't add a default network; it certainly doesn't do that when connected to qemu:///system - many users don't want any libvirt networks).
Still, then, what would be best way to have some initial configuration for qemu:///session?
The configuration in question is two networks, to use bridges that are set up on this system to be usable unprivileged with qemu-bridge-helper.
If you're creating the guests with virt-install and don't specify a particular network connection, it will add a usermode network interface, so adding a libvirt network pointing at an existing bridge isn't going to help you. Instead, you can just tell them that if they want [better/different/whatever] network connection, they should connect to the bridges you mention. e.g. in virt-install they would add: --network bridge=$bridgeblah to the commandline. That seems just as simple (especially if you give the bridges descriptive names).
Since I can't control, and don't want to try to control, what libvirt-consuming applications are run by the user, that method is out.
So is there some way I can put the configuration in /etc/skel and have the UUID be autogenerated?
If the file was placed in the correct location by something other than libvirt, then libvirtd would read it, see that there was no UUID, so it would autogenerate the UUID (but wouldn't write this new UUID back to the config file). That would work fine until libvirtd was terminated (due to timeout after not using it, or due to rebooting the host, etc). The next time libvirtd was run, it would again see the UUID was missing, autogenerate one (different this time!), etc. Would that cause a problem? Dunno, haven't tried. I can't think of a problem internal to libvirt. Of course putting stuff in /etc/skel only works for *new* users though, right? What about existing users?
Or am I going to have to write a script to be run on user-creation, to generate new UUIDs for each new user? Or does it not matter that all the network resources under the different users have the same UUIDs?
Since the session-mode libvirtd's don't communicate with each other in any way, I seriously doubt that would ever cause a problem.
participants (3)
-
catern＠catern.com -
Daniel P. Berrange -
Laine Stump