== Setup a new kvm domain fast ==
+=== guest setup ===
+
+or: how to install Debian.
+
Define a shell function
{{{
setup_env() {
echo -n "New hostname: " &&
export LC_ALL=C &&
- read host &&
- target=/mnt/target &&
+ read guest &&
+ target="/mnt/target-$guest" &&
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" &&
+ vgdefault=`vgdisplay -c | awk -F: '{print $1;exit}' | sed 's/ *//g'` &&
+ echo -n "Volume group? [$vgdefault]: " &&
+ read vg &&
+ if [ "$vg" = "" ]; then vg="$vgdefault"; fi &&
+ echo -n "Use lvm for non-swap partitions? [Y/n] " &&
+ read use_lvm &&
+ if [ "$use_lvm" = "n" ]; then
+ : SAN, as in the msa2012i at ubcece &&
+ : requires that it is already setup &&
+ dev_root="/dev/mapper/$guest-root" &&
+ dev_boot="/dev/mapper/$guest-boot" &&
+ echo "Root device will be $dev_root" &&
+ echo "Boot device will be $dev_boot" &&
+ echo "Make sure they exist already." &&
+ fs=xfs
+ else
+ use_lvm="y" &&
+ dev_root="/dev/mapper/$vg-$guest--root" &&
+ dev_boot="/dev/mapper/$vg-$guest--boot" &&
+ echo "Root device will be $dev_root" &&
+ echo "Boot device will be $dev_boot" &&
+ fs=ext4
+ fi &&
+ if [ "$vg" != "" ]; then
+ dev_swap="/dev/mapper/$vg-$guest--swap"
+ elif [ -d /SWAPFILES ]; then
+ dev_swap=/SWAPFILES/$guest-swap
+ else
+ echo "No idea how to do swap" && false
+ fi &&
+ echo -n "Use a /boot filesystem (strongly recommended)? [Y/n] " &&
+ read use_boot &&
+ echo "Swap device will be $dev_swap" &&
+ echo "fs is $fs"
echo "Chosen mirror is $mirror"
}
}}}
Then install base:
+The way we lay out the filesystems by default is that we have one 4g /
+filesystem, a swap, and a tiny boot filesystem. On the host we make
+a new LVM logical volume for each of the three. Only the LV that will
+take the guest's boot will actually be partitioned - into a single boot
+partition. That's so we can install grub into the MBR and have the system
+start just like a real system. Root and swap are put directly onto the
+logical volume, without partitioning it at all. This makes getting to the
+data from the host easier - no need to run kpartx - and it makes growing
+trivial.
+
{{{
#######
# install base
- apt-get install debootstrap kpartx &&
- lvcreate -L 128m -n "$host"-boot /dev/"$vg" &&
- lvcreate -L 4g -n "$host"-root /dev/"$vg" &&
- lvcreate -L 4g -n "$host"-swap /dev/"$vg" &&
+ apt-get install debootstrap debian-archive-keyring kpartx &&
+ if [ "$use_lvm" = "y" ]; then
+ if [ "$use_boot" != "n" ] ; then
+ lvcreate -L 128m -n "$guest"-boot /dev/"$vg"
+ fi &&
+ lvcreate -L 4g -n "$guest"-root /dev/"$vg"
+ fi &&
+ lvcreate -L 4g -n "$guest"-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"/"$host"-swap &&
+ if [ "$use_boot" != "n" ] ; then
+ ( echo ',,L,*' | sfdisk -D "$dev_boot" ) &&
+ kpartx -v -a "$dev_boot" &&
+ mkfs."$fs" "$dev_boot"1
+ fi &&
+ mkfs."$fs" "$dev_root" &&
+ mkswap "$dev_swap" &&
: &&
mkdir -p "$target" &&
- mount /dev/"$vg"/"$host"-root "$target" &&
- mkdir -p "$target/boot" &&
- mount /dev/mapper/"$vg"-"$host"--boot1 "$target/boot" &&
+ mount "$dev_root" "$target" &&
+ if [ "$use_boot" != "n" ] ; then
+ mkdir -p "$target/boot" &&
+ mount "$dev_boot"1 "$target/boot"
+ fi &&
cd "$target" &&
- debootstrap --variant=minbase lenny . "$mirror"
+ debootstrap --variant=minbase --keyring=/usr/share/keyrings/debian-archive-keyring.gpg squeeze . "$mirror"
}}}
And finalize the setup:
{{{
#######
# finish setup
- echo "$host" > etc/hostname &&
+ echo "$guest" > etc/hostname &&
cat > etc/hosts << EOF &&
127.0.0.1 localhost
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/ &&
+ ( ! [ -e /etc/apt/preferences ] || 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
+ chroot . apt-get install -y net-tools iproute ifupdown dialog vim netbase xfsprogs &&
+ cp -av `readlink -f $dev_root` dev/`basename $dev_root` &&
+ DEBIAN_FRONTEND=noninteractive chroot . apt-get install -y grub2 &&
+ cat > etc/kernel-img.conf << EOF &&
+do_symlinks = no
+do_initrd = yes
EOF
- # install a kernel image
- echo -e "do_symlinks = yes\nlink_in_boot = yes\ndo_initrd = yes" > etc/kernel-img.conf &&
- chroot . apt-get install linux-image-2.6-amd64
-
+ if [ "$use_boot" != "n" ] ; then
+ cp -av `readlink -f $dev_boot` dev/`basename $dev_boot` &&
+ cp -av `readlink -f $dev_boot""1` dev/`basename $dev_boot`1 &&
+ chroot . grub-install --modules=part_msdos /dev/`basename $dev_boot` &&
+ # install a kernel image
+ chroot . apt-get install -y linux-image-2.6-amd64 &&
+ sed -i -e 's/^#GRUB_TERMINAL=console/GRUB_TERMINAL=console/' etc/default/grub &&
+ echo "(hd0) /dev/`basename $dev_boot`" > boot/grub/device.map &&
+ chroot . update-grub &&
+ sed -i -e "s#dev/`basename $dev_boot`1#dev/hda1#g" boot/grub/grub.cfg &&
+ rm -v dev/"`basename $dev_boot`" dev/"`basename $dev_boot`1"
+ else
+ echo && echo && echo && echo "Hardly tested, expect this to fail." && echo && echo && echo &&
+ echo "(hd0) /dev/`basename $dev_root`" > boot/grub/device.map &&
+ chroot . grub-install /dev/"`basename $dev_root`" &&
+ # install a kernel image
+ chroot . apt-get install -y linux-image-2.6-amd64 &&
+ sed -i -e 's/^#GRUB_TERMINAL=console/GRUB_TERMINAL=console/' etc/default/grub &&
+ chroot . update-grub
+ fi &&
+ sed -i -e "s#dev/`basename $dev_root`#dev/vda#g" boot/grub/grub.cfg &&
+ rm -v boot/grub/device.map &&
+ rm -v dev/"`basename $dev_root`"
}}}
And a fstab and a boot loader config
{{{
# doesn't work: chroot . update-grub
- rootuuid=`vol_id /dev/"$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=$rootuuid ro
-initrd /initrd.img
-
-### END DEBIAN AUTOMAGIC KERNELS LIST
-EOF
+ rootuuid=`blkid -s UUID -o value "$dev_root"` &&
+ swapuuid=`blkid -s UUID -o value "$dev_swap"` &&
+ if [ "$fs" = "ext4" ]; then
+ rootopts="errors=remount-ro"
+ else
+ rootopts="defaults"
+ fi
cat > etc/fstab << EOF &&
-UUID=$rootuuid / ext3 errors=remount-ro 0 1
-UUID=$bootuuid /boot ext3 defaults 0 2
+UUID=$rootuuid / $fs $rootopts 0 1
UUID=$swapuuid none swap sw 0 0
EOF
+ if [ "$use_boot" != "n" ] ; then
+ bootuuid=`blkid -s UUID -o value "$dev_boot"1` &&
+ echo "UUID=$bootuuid /boot $fs defaults 0 2" >> etc/fstab
+ fi
cat > etc/network/interfaces << EOF
auto lo
iface lo inet loopback
vi etc/network/interfaces
}}}
+And set a password:
+{{{
+chroot . passwd
+}}}
+
+Set a nameserver config that works once the VM has booted. Later in the process we will install unbound anyway.
+{{{
+cat > etc/resolv.conf << EOF
+nameserver 8.8.8.8
+search debian.org
+EOF
+}}}
+
And unmount:
{{{
cd / &&
- umount "$target"/boot &&
+ if [ "$use_boot" != "n" ] ; then
+ umount "$target"/boot &&
+ kpartx -v -d "$dev_boot"
+ fi &&
umount "$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.
+=== virsh setup ===
+
+Setup a new kvm domain by creating a new file in /etc/dsa-kvm/`hostname/$guest.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 help}}}
** {{{virsh define foo.xml}}}
** {{{virsh start foo}}}
** {{{virsh destroy foo}}}
** {{{virsh vncdisplay foo}}} (and ssh -L 5900:localhost:<5900+x> $host and vnc localhost)
+
+=== post processing ===
+
+Do not forget to set a sane root password before installing ssh in the new kvm domain.
+
+=== when stuff goes wrong ===
+
+To get to the guest data from the host:
+
+{{{
+ setup_env
+ kpartx -v -a "$dev_boot" &&
+ mkdir -p "$target" &&
+ mount "$dev_root" "$target" &&
+ mkdir -p "$target/boot" &&
+ mount "$dev_boot"1 "$target/boot"
+}}}
+
+and once you're done:
+{{{
+ cd / &&
+ umount "$target"/boot &&
+ umount "$target" &&
+ kpartx -v -d "$dev_boot" &&
+ rmdir "$target"
+}}}
+
+Make sure that the filesystem isn't being mounted twice - i.e. never start the guest while the filesystems are mounted, and never mount them while the guest is running.