As hrw pointed out on #ubuntu-devel, a third option is to simply add
devtmpfs dev devtmpfs defaults 0 0
to /var/lib/lxc/$c/fstab
As hrw pointed out on #ubuntu-devel, a third option is to simply add
devtmpfs dev devtmpfs defaults 0 0
to /var/lib/ lxc/$c/ fstab