QEMU Monitor Protocol

QEMU Monitor Protocol (QMP) is a JSON-based protocol that allows applications to communicate with a QEMU instance. The qemu-monitor-command provided by the virsh shell allows users to interact with the QEMU monitor from the command line.

To enumerate all available QMP commands for a particular virtual machine, run the following:

#virsh qemu-monitor-command 
<vm_name> ––pretty '{"execute":"query-commands"}'

There are many query commands that can expose a lot of internal information that is not exposed to OpenStack and is vital for effective root cause analysis. For example, query-block returns detailed information about block devices being used by the virtual machine.

#virsh qemu-monitor-command instance-00000002 --pretty '{"execute":"query-block"}
{
  "return": [
      {
          "io-status": "ok",
          "device": "drive-virtio-disk0",
  ...