Another feature I'd like to provide in libvirt LXC is "hotplug" of NIC devices to containers. eg, I have a NIC eth1 in the host and I want to make it appear as eth0 in the container. There are two ways I can do this # ip link set eth1 name eth0 # ip link set eth0 ns $PID Or # ip link set eth1 ns $PID # setns --net $PID (assume it opens /proc/$PID/ns/net & does setns(fd)) # ip link set eth1 name eth0 Both these approaches suffer from flaws though. The first approach fails on step one, if there is already another NIC in the host, that has the same name as the target we want to use in the container. The second approach fails on step 1 if there is already a NIC in the container which has the same name as the original device on the host. To get around this, we'd basically need to temporarily use a completely random NIC name eg # ip link set eth1 name $RANDOMNAME # ip link set $RANDOMNAME ns $PID # setns --net $PID (assume it opens /proc/$PID/ns/net & does setns(fd)) # ip link set $RANDOMNAME name eth0 This is workable, but feels slightly unpleasant. So IMHO if would be desirable if the kernel allowed us to atomically change the NIC device name and namespace at the same time. eg # ip link set eth1 name eth0 ns $PID Although that 'ip' CLI syntax is allowed, it appears to implement it in two steps, doing the rename first and then setting the namespace, so you still hit the NIC name clash problem. 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 :| _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
