Package: ifupdown Version: 0.8.19 This code in /lib/udev/ifupdown-hotplug just fails when there is is another ifup running at the same time:
| local out=$(ps -C ifup ho args) | if [ "${out%$INTERFACE*}" != "$out" ]; then | mesg "Already ifup-ing interface $INTERFACE" | exit 0 | fi When tracing the execution of that, this is the result: | + local out=ifup --allow=hotplug veth-foo | /lib/udev/ifupdown-hotplug: 70: local: veth-foo: bad variable name The result is, obviously, that the interface simply stays unconfigured. Commenting out that block seems to "solve" the problem.