Debugging the Virtualization Layer (libvirt and QEMU) in OpenStack

Virtualization drivers (e.g. libvirt, QEMU/KVM) are the core part of OpenStack Compute layer. An OpenStack environment is challenging to debug as is -- more so when multiple Compute nodes and thereby multiple libvirt daemons and QEMU instances are involved. A good grasp of Virtualization debugging mechanisms is vital for effective root cause analysis. To that end, libvirt and QEMU provide a rich set of debugging controls that allow us to query (or modify) the state of virtual machines in distres