Jeff Dike makes virtualization predictions
Posted by Fraser Campbell Thu, 18 Jan 2007 04:33:00 GMT
linux.com yesterday published an interview with Jeff Dike (author/maintainer of UML). The linux.com interview is available at http://www.linux.com/article.pl?sid=07/01/16/2037250.
It sounds likely that UML will soon be ported to make use of hardware virtualization extensions. This support will be via the KVM kernel subsystem.
Many interesting twists to this story:
- Xen popularizes paravirtualization
- Xen doesn’t get mainline kernel port
- VMware gets on the bandwagon with VMI proposal
- finally paravirt support starts creeping into the kernel
- KVM jumps into the fray (out of the blue)
- KVM now uses paravirt support
- along comes the grand-daddy of Linux virtualization (UML) building on top of both KVM and paravirt
- still no Xen in mainline support
On a related note, Jeff made a very interesting presentation last summer at OLS. The paper was entitled “Linux as a Hypervisor” and can be downloaded as part of the 2006 OLS Proceedings Volume 1.
In this paper Jeff argues that the Linux kernel itself is a very capable virtualization manager. He points out that many of the “fancy” new features being added to the kernel in the past few years have had great benefits for virtualization (async and direct I/O primarily are mentioned).
Another interesting part of the paper was that he mentioned namespace virtualization patches (containers) and how they can be a boon to UML as well by allowing processes to make system calls directly on the host kernel.
One could definitely forsee that hypervisors might be irrelevant before too long. The linux kernel has most of the features that virtualization solutions need (NUMA, SMP, AIO, DIO, volume management, memory management, etc, etc, etc.) why duplicate all of code in a hypervisor as well – UML kernels as a very thin wrapper around the host kernel could yet become the sweetest deal of all.
