User Mode Linux

ben017f · 2006-01-30 10:30:45

Well, I've built a 2.6.15 UML kernel package and I made a filesystem using archbootstrap... I've been wrestling with it for several hours now and I FINALLY have it booting... kind of!
I've had to boot into runlevel 1 and then run init 3 otherwise it hangs! and I also had to follow the "Automatically login some user to a virtual console on startup" to get round agetty being a pain!
Is anyone still playing with UML and does anyone have any similar horror stories (or fixes ) to share..?[/url]

ben017f · 2006-01-31 12:00:28

WOW, i must a boring bastard!! 67 views and no comments!!

Well, I've now build a root filesystem around busybox, which was nice and small before i pacman'd glibc into it... it's now gone up to 134M of which 48M is due to /usr/lib/locale... I want to get rid of as much of this as i can, but i don't know what i can get away with!!

I'd also like to get pacman working properly, but i think i might have trouble with dependancy checking as the only thing i actually have installed is glibc, udev and bash, everything else is from busybox.

Any help would be greatly appreciated!!

iphitus · 2006-01-31 12:17:53

sounds awesome, keep us updated. uml is a very interestin thing.

Lone_Wolf · 2006-01-31 19:42:28

Not boring.

I was one of the people who read this, but didn't know what to respond at that time.
Looking at the description of UML it seems similar to running a virtual machine with qemu, vmware, Xen but a lot more difficult to set up.

I would be interested to hear more.

ben017f · 2006-02-02 00:00:00

A really good place to go for UML stuf is www.netkit.org it's a set of scripts plus a kernel and debian filesystem for controlling UML instances. There's also a really good section of networking turorials, using a network you've built out of UML machines to teach.

What I'm trying to achieve is similar, but I want to build a GUI front-end in python, with drag and drop funtionality to build the network. I also want to be able to run as many as possible on my laptop (512Mb RAM which I may increase as I progress) so I'm trying for as small a footprint as possible with both the filesystem and memory requirements. This is something I haven't got much experience with so any pointers from people (perhaps from an emgedded background) would be helpful! I envisage this, when it's finished, as either a teaching tool for TCP/IP, and/or a tool for organisations to test network configurations as fast and cheeply as possible.

At the moment, the root file system is at 48M; as I mentioned before glibc has really bumped that up so I may look at an alternative clib for later versions. This is running on busybox for all of my executables so far and at the moment I'm using

pacman -Sd <package>

to install new packages and then

ldd <executable>

to find any other library files I need and copy them from the host machine.

Any ideas, points, mistakes, improvements, general abuse would be gratefuly recieved! [/code]

Romashka · 2006-02-02 15:06:57

Lone_Wolf wrote:

Looking at the description of UML it seems similar to running a virtual machine with qemu, vmware, Xen but a lot more difficult to set up.

UML is not virtual machine. It is simply a modified kernel that runs as a process inside host system. Filesystem can be in one huge file or on dedicated partition. Hardware is shared with host system. The most useful feature is COW (copy on write). There are few ways to setup networking.
UML is good for trying something without scare of breaking something. There are also several hosting companies that uses UML for virtual hosts. UML is 10-20% slower than real system, with ska patch for host kernel it can be almost as fast as Xen (but patching host kernel will make it less secure).
I've played with UML few years ago on LFS. I had no problems with it, but that was 2.4 kernel.

Arch Linux

#1 2006-01-30 10:30:45

User Mode Linux

#2 2006-01-31 12:00:28

Re: User Mode Linux

#3 2006-01-31 12:17:53

Re: User Mode Linux

#4 2006-01-31 19:42:28

Re: User Mode Linux

#5 2006-02-02 00:00:00

Re: User Mode Linux

#6 2006-02-02 15:06:57

Re: User Mode Linux

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