== Setup a new kvm domain fast ==

Define a shell function

{{{
# set up environment
setup_env() {
 echo -n "New hostname: " &&
 export LC_ALL=C &&
 read host &&
 target=/mnt/target &&
 mirror=`cat /etc/apt/sources.list /etc/apt/sources.list.d/debian.list 2>/dev/null | awk '/^deb.*debian/ {print $2; exit}'` &&
 vg=`vgdisplay -c | awk -F: '{print $1;exit}' | sed 's/ *//g'` &&
 echo "Chosen vg is $vg" &&
 echo "Chosen mirror is $mirror"
}
}}}

And run it

{{{
setup_env
}}}

Then install base:

{{{
#######
# install base

 apt-get install debootstrap kpartx &&
 lvcreate -L 128m -n "$host"-boot /dev/"$vg" &&
 lvcreate -L 4g -n "$host"-root /dev/"$vg" &&
 lvcreate -L 4g -n "$host"-swap /dev/"$vg" &&
 : &&
 ( echo ',,L,*' | sfdisk /dev/"$vg"/"$host"-boot ) &&
 kpartx -v -a /dev/"$vg"/"$host"-boot &&
 mkfs.ext3 /dev/mapper/"$vg"-"$host"--boot1 &&
 mkfs.ext3 /dev/"$vg"/"$host"-root &&
 mkswap /dev/"$vg"/"$host"-swap &&
 : &&
 mkdir -p "$target" &&
 mount /dev/"$vg"/"$host"-root "$target" &&
 mkdir -p "$target/boot" &&
 mount /dev/mapper/"$vg"-"$host"--boot1 "$target/boot" &&

 cd "$target" &&
 debootstrap --variant=minbase lenny . "$mirror"
}}}

And finalize the setup:

{{{
#######
# finish setup
 echo "$host" > etc/hostname &&
 cat > etc/hosts << EOF &&
127.0.0.1       localhost

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
EOF
 rm -fv etc/apt/sources.list &&
 ( ! [ -e /etc/apt/sources.list ] || cp /etc/apt/sources.list etc/apt/sources.list)
 (cp -v /etc/apt/sources.list.d/* etc/apt/sources.list.d/ || true ) &&
 cp -v /etc/apt/preferences etc/apt/ &&
 apt-key exportall | chroot . apt-key add - &&
 chroot . apt-get update &&
 echo "Apt::Install-Recommends 0;" > etc/apt/apt.conf.d/local-recommends &&
 chroot . apt-get install net-tools iproute ifupdown dialog vim netbase &&
 #chroot . apt-get remove --purge cpp dpkg-dev g++ gcc gcc-4.2-base libatm1 libdevmapper1.02.1 libgpm2 libc6-dev linux-libc-dev libstdc++6-4.3-dev binutils cpp-4.3 gcc-4.3 gettext-base libgmp3c2 libgomp1 libmpfr1ldbl libtimedate-perl
 # don't - it may start daemons
 #chroot . apt-get dist-upgrade
 chroot . apt-get install grub &&
 cp -av usr/lib/grub/x86_64-pc boot/grub &&
 grub << EOF &&
device (hd0) /dev/mapper/$vg-$host--boot
root (hd0,0)
setup (hd0)
quit
EOF
 # install a kernel image
 echo -e "do_symlinks = yes\nlink_in_boot = yes\ndo_initrd = yes" > etc/kernel-img.conf &&
 chroot . apt-get install linux-image-2.6-amd64

}}}

And a fstab and a boot loader config

{{{
 # doesn't work: chroot . update-grub
 rootuuid=`vol_id /dev/"$vg"/"$host"-root "$target" | awk -F= '$1=="ID_FS_UUID" {print $2}'` &&
 swapuuid=`vol_id /dev/"$vg"/"$host"-swap "$target" | awk -F= '$1=="ID_FS_UUID" {print $2}'` &&
 bootuuid=`vol_id /dev/mapper/"$vg"-"$host"--boot1  | awk -F= '$1=="ID_FS_UUID" {print $2}'` &&
 cat > boot/grub/menu.lst << EOF &&
default 0
timeout 5
color cyan/blue white/blue

### BEGIN AUTOMAGIC KERNELS LIST
# kopt=root=UUID=$rootuuid ro

## ## End Default Options ##
title Debian
root (hd0,0)
kernel /vmlinuz root=UUID=$rootuuid ro
initrd /initrd.img

### END DEBIAN AUTOMAGIC KERNELS LIST
EOF
 cat > etc/fstab << EOF &&
UUID=$rootuuid    /               ext3    errors=remount-ro 0       1
UUID=$bootuuid    /boot           ext3    defaults        0       2
UUID=$swapuuid    none            swap    sw              0       0
EOF
 cat > etc/network/interfaces << EOF
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual
  pre-up ip link set up dev \$IFACE
  post-down ip link set down dev \$IFACE
EOF
}}}

Maybe fix/setup networking properly:

{{{
vi etc/network/interfaces
}}}

And unmount:

{{{
  cd / &&
 umount "$target"/boot &&
 umount "$target" &&
 kpartx -v -d /dev/"$vg"/"$host"-boot &&
 rmdir "$target"
}}}

Setup a new kvm domain by creating a new file in /etc/dm-virt/`hostname/$host.xml.

* Properly configure hostname
* Pick a new uuid ({{{uuidgen}}})
* Setup block devices properly
* pick a new and unique mac address (on d.o every kvm host has their own mac address space and the last block is changed for the guests, as in {{{..:..:..:..:<host byte>:<guest byte>}}}. )
* virsh commands:
** {{{virsh define foo.xml}}}
** {{{virsh start foo}}}
** {{{virsh destroy foo}}}
** {{{virsh vncdisplay foo}}} (and ssh -L 5900:localhost:<5900+x> $host  and  vnc localhost)