Building a QEMU management tool

Back in November last year I moved from working as a consultant in Red Hat‘s Global Professional Services divison, back to being a member of Engineering. The first project I’ve been involved in is the $100 Laptop, in particular looking at how we can run OS images without needing the real hardware. We quickly identified QEMU as being a reasonable starting point on which to build out a basic ‘Laptop Simulator’. The base QEMU engine is command line driven, and although there is KQEMU and GTK QEMU provide some form of management frontend, neither was entirely satisfactory.

VMWare GSX server has a basic API which lets one create and control virtual machines from Perl. The API, however, was clearly tacked onto the admin UI as an afterthought, and while the capabilities it exposes are very useful, one is frustrated by the bits not exposed to the API. Anticipating the need to construct autmated test harnesses to control QEMU virtual machines, it was clear that any management tool for QEMU must treat its API as a first-class peer to the actual UI. In addition exposing the API as Perl limits the level of interoperability for developers who might want to write their tools in C, or Python, or Java. Being an active member of the DBus community, the answer to this goal was clear:

1. Write a management API as a DBus service
2. Write a completely separate admin UI as a DBus client

After a few weeks hard work, we now have not only a DBus service for managing QEMU, but a general purpose Python admin UI providing similar levels of functionality to that of VMWare GSX server, a command line Perl tool for quickly launching pre-built OS images with a virtual hardware configuration aligned to that of the $100 laptop, and the beginnings of an automated test suite. The full code trees will be opened up to the community over the next few weeks, but as a taster of what’s to come, there is a flash movie here