It's not possible to start a VM with a network cable unplugged

[Uqbar]

There should be a command line (sub)option to unplug a network cable.
While from the monitor interface I can issue:

set_link virtio-net-pci.0 off

There's no way to fire a VM from command line with that cable already unplugged.
As an example, virtualbox can do it.

[timsoft (tim-tree-of-life)]

this would be really useful for testing resilliance and auto fall-over systems in a vm, to be able to quickly virtually "unplug" a network connection.

[Daniel Berrange (berrange)]

Note that you can start QEMU with the "-S" flag which means CPUS are paused. This gives you ability to run the "set_link" monitor command above, and then run "cont" to actually start the VM. Less convenient that a CLI flag, but functionally it is eqivalent.

[Thomas Huth (th-huth)]

The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now.
If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience.

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]