Re: VKernel progress update - 9 Jan 2006

["Kevin L. Kane" <kevin.kane@xxxxxxxxx>]

>     The linux code is fairly opaque.  It is almost universally without any
>     code comments so I am not sure whether they are using a real page table
>     (requiring UML to run as root), or whether they are using a virtualized
>     page table like we are (which allows us to run without needing root
>     creds).  Inquiring minds want to know!

  Based on reading this page:  http://user-mode-linux.sourceforge.net/run.html

UML does NOT need to be run as root.

-Kevink

On 1/11/07, Matthew Dillon <dillon@apollo.backplane.com> wrote:
> :On Wed, January 10, 2007 8:44 pm, Gergo Szakal wrote:
> :
> :> Uhm, from the user's point of view: how about an rc.conf-like file
> :> (rc.vkernel) to store this values?
> :
> :Perhaps as a switch when running the kernel, so that alternate files can
> :be specified?  Of course, it's easy for me to suggest what I don't know
> :how to implement...
>
>     I don't think we'll have an /etc/vkernel.conf for this release, but
>     it is absolutely needed for any production use.
>
>     I can imagine a system which uses several vkernels in production
>     (possibly even 'many' vkernels).  Clearly some sort of config file
>     is needed to start up the vkernels and to manage and maintain their
>     operation (or at least detect when something goes wrong and complain
>     about it).
>
>     Even more importantly, the biggest resource used by a vkernel that
>     cannot be automatically allocated is its ROOT disk.  We have several
>     choices here, including NFS boot over the TAP/NKE.  To make it really
>     useful, though, we need a disk managment layer.  Again, not this
>     release, but the writing is on the wall.  We need one.
>
>     Post-release (end of january) I will be shifting gears over to the
>     SYSLINK and CCMS subsystems (clustering and cache coherency).  I
>     want other developers to take up the ball on the virtual kernel and
>     flesh it out, now that the hard part is done.   I did the virtual kernel
>     core for entirely selfish reasons :-) it makes kernel development a
>     whole lot easier.  Clearly there are major production uses for virtual
>     kernels as well and I need the rest of our development community to
>     develop those uses!
>
>     Linux has something similar (UML), but no BSD system has this feature.
>     All the BSDs rely on third party hardware virtualization (vmware, xen,
>     qemu, etc).
>
>
>                                         -Matt
>                                         Matthew Dillon
>                                         <dillon@backplane.com>


--
Kevin L. Kane
kevin.kane at gmail.com