On 6/10/07, zethix or something zethix@gmail.com wrote:
On 6/9/07, Aaron Kaplan aaron@lo-res.org wrote:
On Jun 9, 2007, at 1:57 PM, Axel Neumann wrote:
I am currently trying to get a grip on vnuml ( http://www.dit.upm.es/vnumlwiki/index.php/Tutorial )
which has good
howtos and tutorial for building host- and uml- kernels and root_fs.
Especially vnuml offers a framework for virutal network configuration based on xml-configuration files. I think texas-kernel is also patched for vnuml enhancements but for texas's root_fs and network-configuration scripts I am not shure. Maybe aaron can provide some more background on that?
I _think_ zethix (in the CC) briefly looked into vnuml but it seemed to complicated. The scripts were all borked and quite unusable for us at least.
Yes, as far as I remember, vnuml needs a lot of things in order to work... well, things that all linux distros usually have, but not busybox. It was something like ... install its boot scripts in the vnuml'd system, make it mount an fs on the host, then use ssh for something and so on and so on. But the biggest problem we had was actually... that it was constantly making our poor system crash. Anyway, I guess we just had to drop it in order to move on. I do believe there are some nice things about vnuml, but ...
In order to releas texas from unproductive trial-and-error configuration testing (and feeling less intervening when applying core-kernel- patches or installing new system-libraries) I started to setup a small vnuml environment on my home-pc. Therefore I found also the following links quite useful:
http://www.enic.fr/people/landru/viminal/vnuml.gentoo/how-to/vnuml-
gentoo-guide.html ( gentoo oriented setup, host-kernel-enhancement, uml-kernel, root_fs )
http://www.dit.upm.es/vnumlwiki/index.php/Howto ( further links for root_fs howtos )
@aaron: do you have a link explaining from-scratch busybox-based uml-rootfs generation (as being used on texas) ?
yes
with an existing root_fs:
mount -o loop root_fs /mnt then just copy over things as needed. That is what I did . works!
To create an initial root_fs:
dd if=/dev/zero of=roof_fs bs=1M count=XXX Then mount this root_fs from inside an existing UML instance and fdisk it (./linux ubd1=root_fs ) and mkfs it
voila!
a.
PS: zethix was recently working on a way to do the simulation completely without UML but with olsr_switch which has still some bugs. Maybe some similar batman_switch application can be usefull?
Briefly, the olsr_switch works like this: in olsrd, there is this special 'driver' that doesn't use a netif for transmission, but a tcp connection instead. that connection goes to the olsr_switch. Also, there are some patches preventing all instances to modify the same routing table. So, in order to make batman work with olsr_switch (or whatever) I guess modifications might be needed.
There is also an N-th way of doing it, probably: pseudo interfaces (like tap) instead of tcp connections. Nevertheless, all batmans (or olsrds) will share the same routing table.
What about using OpenVZ instances (each instance has its own TCP IP stack I think)?
I did not manage to have a working 32bit UML kernel+busybox rootfs for testing OLSR and/or batman (ifconfig did not work out with the busybox rootfs version of http://uml.nagafix.co.uk/BusyBox-1.5.0/BusyBox-1.5.0-x86-root_fs.bz2 and kernel version vmlinux-2.6.18.1-bb2), if someone can recommend me one version for each of those.
-- Benjamin Henrion <bhenrion at ffii.org> FFII Brussels - +32-484-566109 - +32-2-4148403