Proxmox: QEMU Guest Agent is not running — qmp command ‘guest-ping’ failed

Hey fellow Internet dweller, are you worried about the following message appearing during backup of a suspended virtual machine in Proxmox?

...
INFO: suspend vm
INFO: creating archive '...'
Qemu Guest Agent is not running - VM ### qmp command 'guest-ping' failed - got timeout
...

Then you should ask yourself a question, how can the QEMU guest agent in the virtual machine answer the “guest-ping” request while its virtual machine is suspended?

(Pay attention to the INFO: suspend vm line appearing before the message).

Of course it cannot, so maybe you shouldn’t worry that much.

One thing you can try to calm yourself down is to test the communication with the VM from the host while the VM is not suspended:

qm agent <id> ping

If the the QEMU guest agent is reachable, the command will complete without any output.

If you’re using Windows as a guest OS, you can (re)install the QEMU guest agent from a virtio-win iso.