I'm not responsible for what happens if you use this.

But if you want to anyway:

Step 1. Create a child that has its own setting for where disk images go. (my version defaults to /home/spencertipping/images)

$ ./uml-machine child ./my-uml-machine $ ./my-uml-machine root-directory = /home/myname/images # (can be other things too)

From now on you'll use this child. The nice thing is that the Perl scripts know not to overwrite the root-directory even when you're doing upgrades.

Step 2. Use that child to create a new Arch Linux instance.

$ ./my-uml-machine child my-arch-instance $ ./my-arch-instance check # important! tells you what to do next $ ./my-arch-instance create-image # takes an optional number of GB, defaults to 2 $ ./my-arch-instance arch-init-image $ ./my-arch-instance run

At this point your system is booted. You can change the amount of memory (defaults to 128M) and the terminal emulator (defaults to 'terminal'):

$ ./my-arch-instance memory 128M $ ./my-arch-instance memory = 512M $ ./my-arch-instance xterm terminator,-T,-x $ ./my-arch-instance xterm = 'gnome-terminal,-t,-x'

The script also knows how to do some other tasks:

$ ./my-arch-instance rescue # bash prompt inside mounted FS $ ./my-arch-instance ip-address $ ./my-arch-instance prefix # all files live in here $ ./my-arch-instance nuke-image # nuke the disk image and accompanying files

Note that you can't run an instance more than once, or do anything squirrelly like that. The reason is that the Perl script disables its execute bit while it's busy.

Step 3. Later on, do a git pull and have everything update.

$ git pull $ for file in *; do ./$file update -n done

You can also have your machines update even if you've moved them into a different directory. Just run ./my-machine update-from /path/to/uml-machine -n, and it will remember the path to uml-machine so that ./my-machine update -n works in the future.

Alternatives to Arch are Debian and Gentoo, specified by using debian-init-image and gentoo-init-image, respectively. Each distribution caches most of its downloads, so the first install takes much longer than subsequent ones. Gentoo is a disk hog, so it needs a bigger image; I use this:

$ ./my-gentoo-instance create-image 4 # 4GB instead of 2GB

Once your instance is running, a command called /sbin/netup should get networking going between the host and other UML instances. It also initializes the routing table so that your instance can connect to the Internet.

Right now only one instance can have Internet connectivity at a time. This is because I'm using tun/tap to interface to the host, and each tap interface requires root privileges to configure (so I'm using only one tap interface). I would like to fix this, however, ideally with a virtual network and a bridge.