Hi,
I just upgraded qemu to 7.2.0. Since then, lxd cannot create VMs with networking. Error indicator: Monitor is disconnected. My searches for prior documentation point at a QMP-related issue.
Below, trying to launch a VM attached to the lxdbr0 network.
# lxc launch --vm images:alpine/edge -c security.secureboot=false -n lxdbr0
Creating the instance
Instance name is: loyal-midge
Starting loyal-midge
Error: Failed setting up device via monitor: Failed setting up device "eth0": Failed adding NIC netdev: Monitor is disconnected
Try `lxc info --show-log local:loyal-midge` for more info
With a default profile without networking:
# lxc launch --vm images:alpine/edge -c security.secureboot=false
Creating the instance
Instance name is: thankful-gannet
The instance you are starting doesn't have any network attached to it.
To create a new network, use: lxc network create
To attach a network to an instance, use: lxc network attach
Starting thankful-gannet
Rebooting the VM with a nic.
# lxc stop thankful-gannet
# lxc network attach lxdbr0 thankful-gannet
# lxc start thankful-gannet
Error: Failed setting up device via monitor: Failed setting up device "lxdbr0": Failed adding NIC netdev: Monitor is disconnected
Try `lxc info --show-log thankful-gannet` for more info
lxd debug output
DEBUG [2022-12-17T18:15:37Z] Skipping lxd-agent install as unchanged installPath=/var/lib/lxd/virtual-machines/thankful-gannet/config/lxd-agent instance=thankful-gannet instanceType=virtual-machine project=default srcPath=/opt/lxd-5.9/bin/lxd-agent
DEBUG [2022-12-17T18:15:37Z] Starting device device=lxdbr0 instance=thankful-gannet instanceType=virtual-machine project=default type=nic
DEBUG [2022-12-17T18:15:37Z] Starting device device=root instance=thankful-gannet instanceType=virtual-machine project=default type=disk
DEBUG [2022-12-17T18:15:37Z] UpdateInstanceBackupFile started instance=thankful-gannet project=default
DEBUG [2022-12-17T18:15:37Z] Skipping unmount as in use driver=dir pool=default refCount=1 volName=thankful-gannet
DEBUG [2022-12-17T18:15:37Z] UpdateInstanceBackupFile finished instance=thankful-gannet project=default
DEBUG [2022-12-17T18:15:37Z] Instance operation lock finished action=start err="Failed setting up device \"lxdbr0\": Failed adding NIC netdev: Monitor is disconnected" instance=thankful-gannet project=default reusable=false
WARNING[2022-12-17T18:15:37Z] Failed to collect VM process exit status instance=thankful-gannet instanceType=virtual-machine pid=1214572 project=default
DEBUG [2022-12-17T18:15:37Z] Stopping device device=root instance=thankful-gannet instanceType=virtual-machine project=default type=disk
DEBUG [2022-12-17T18:15:37Z] Stopping device device=lxdbr0 instance=thankful-gannet instanceType=virtual-machine project=default type=nic
DEBUG [2022-12-17T18:15:37Z] UnmountInstance started instance=thankful-gannet project=default
DEBUG [2022-12-17T18:15:37Z] UnmountInstance finished instance=thankful-gannet project=default
DEBUG [2022-12-17T18:15:37Z] Start finished instance=thankful-gannet instanceType=virtual-machine project=default stateful=false
DEBUG [2022-12-17T18:15:37Z] Failure for operation class=task description="Starting instance" err="Failed setting up device via monitor: Failed setting up device \"lxdbr0\": Failed adding NIC netdev: Monitor is disconnected" operation=9fa644a7-4e92-4dbf-a639-548e638e69d4 project=default
Other information
# qemu-system-x86_64 --version
QEMU emulator version 7.2.0 (Debian 1:7.2+dfsg-1)
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers
Thanks