a work for lxc monitor network interface

[Serge Hallyn]

Quoting Libo Chen (clbchenlibo.chen at huawei.com):
> Hello LXC experts,
> 
> 	lxc tool can set network interface by config, but it is static.
> In some scene, the network interface will be dynamic created on the host
> and need be shared to container, but it is not suitable to do by hand,
> so lxc can not work for it.
> 
> 	I also know lxc_user_nic() can only do a part of work, but we have
> two more work:
> 1. grasp the netlink/uevent message about network interface online
> 2. config interface attached to container ip address .
> 
> so it can not fully meet my requirements.
> 
> 	I want there is a monitor can work for network interface hotplug.
> 
> 1. read config form config file, it describe monitor which network interface
>    and what's the network configuration
> 2. grasp the netlink/uevent message about network interface online on the host
> 3. create veth pair, put veth attach to container and bridge
> 4. config the veth attached to container ipaddr
> 
> 			
>          	          netlink  create veth pair
> monitor ---> read config  -------> veth0 attach to container --> config ipaddr
> 				   veth1 attach to bridge
> 
> monitor may be the lxc-start or a child forked by lxc-start.
> 
> 
>  Is this reasonable?  If so, I'd like to do it.

I'm not quite clear on what you're trying to do, but it sounds like you
could use a udev rule, triggered on the nic creation, and use lxc-device
from inside that rule to attach the nic to the container.