[libvirt] Re: [Qemu-devel] [PATCH 1/6] Allow multiple monitor devices (v2)

Avi Kivity wrote: If you live in a world where there is a single management application that provides the only interface to interact with a QEMU instance, then yes, they aren't critical. The problem with this is that most management applications are lossy by their nature. They expose only a subset of functionality supported by QEMU. Currently, the monitor is the "management interface" for QEMU. If we only every support one instance of that management interface, then it means if multiple management applications are to interact with a given QEMU instance, they must all use a single API to do that then allows for multiplexing. I see no reason that QEMU shouldn't do the multiplexing itself though. To put it another way, a user that uses libvirt today cannot see QEMU instances that are run manually. That is not true when a user uses libvirt with Xen today because Xend provides a management interface that is capable of supporting multiple clients. I think it's important to get the same level of functionality for QEMU. N.B. yes, Xend is a horrendous example especially when your argument has been simplicity vs. complexity. At the end of the day, I want to be able to run a QEMU instance from the command line, and have virt-manager be able to see it remotely and connect to it. That means multiple monitors and it means that all commands that change VM state must generate some sort of notification such that libvirt can keep track of the changing state of a VM. Regards, Anthony Liguori