Comment 3 for bug 1187244

we have discuss this issue in the mail list
https://bugs.launchpad.net/nova/+bug/1171636 .

at that time , we can only attach subnets which belongs to the same network . as a workaround , we create only one network for each tenant , tenenat then create subnets in this network , so that user can attach new subnets to an exist vm.

there is another reason ,
as we could attach new subnet to a vm , why cann't we boot with two subnets?