It runs on 2.2.15 or later, and all 2.4 and 2.6 kernels.
Booting UML is straightforward. Simply run 'linux': it will try to
mount the file `root_fs' in the current directory. You do not need to
run it as root. If your root filesystem is not named `root_fs', then
you need to put a `ubd0=root_fs_whatever' switch on the linux command
You will need a filesystem to boot UML from. There are a number
available for download from here
. There are also several
tools which can be used to generate UML-compatible filesystem
images from media.
The kernel will boot up and present you with a login prompt.
Note: If the host is configured with a 2G/2G address space split
rather than the usual 3G/1G split, then the packaged UML binaries will
not run. They will immediately segfault. See
this page for the scoop on
running UML on your system.
The prepackaged filesystems have a root account with
password 'root' and a user account with password 'user'. The
login banner will generally tell you how to log in. So, you log in
and you will find yourself inside a little virtual machine. Our
filesystems have a variety of commands and utilities installed (and it
is fairly easy to add more), so you will have a lot of tools with
which to poke around the system.
There are a couple of other ways to log in:
When you're done using it, run halt, and the kernel
will bring itself down and the process will exit.
On a virtual console
Each virtual console that is configured (i.e. the
device exists in /dev and /etc/inittab runs a getty on it) will come up
in its own xterm. If you get tired of the xterms, read
this to see how to
attach the consoles to something else, like host ptys.
Over the serial line
In the boot output, find a line that looks like:
serial line 0 assigned pty /dev/ptyp1
Attach your favorite terminal program to the corresponding
tty. I.e. for minicom, the command would be
host% minicom -o -p /dev/ttyp1
- Over the net
If the network is running, then you can telnet to the virtual machine
and log in to it. See the
networking page to learn about setting up a virtual network.