Centos 6.3 script to automate creation of the LXC rootfs and libvirt definition

create_libvirt_lxc_guest.sh

#!/bin/bash
# vim: set ts=4 sw=4 et nu
set -e
usage="Usage: $0 <name>"
name=$1
if [ -z "$name" ]; then
	echo $usage
	exit 1;
fi

libvirt_xml="/containers/$name/libvirt.xml"
rootfs="/containers/$name/rootfs"

echo "Initializing rootfs: $rootfs"

mkdir -p $rootfs

mkdir -p $rootfs/home
mkdir -p $rootfs/opt
mkdir -p $rootfs/proc
mkdir -p $rootfs/sys
mkdir -p $rootfs/root
mkdir -p $rootfs/media
mkdir -p $rootfs/mnt
mkdir -p $rootfs/srv
mkdir -p $rootfs/var

for d in bin etc lib lib64 mnt sbin selinux usr var; do
	echo "Copying files /$d ..."
	rsync -ap "/$d/" "$rootfs/$d"
done

rm -rf "$rootfs/var/cache/*"

echo "Creating /dev"

dev_path="$rootfs/dev"
rm -rf $dev_path
mkdir -p $dev_path
mknod -m 666 ${dev_path}/null c 1 3
mknod -m 666 ${dev_path}/zero c 1 5
mknod -m 666 ${dev_path}/random c 1 8
mknod -m 666 ${dev_path}/urandom c 1 9
mkdir -m 755 ${dev_path}/pts
mkdir -m 1777 ${dev_path}/shm
mknod -m 666 ${dev_path}/tty c 5 0
mknod -m 666 ${dev_path}/tty0 c 4 0
mknod -m 666 ${dev_path}/tty1 c 4 1
mknod -m 666 ${dev_path}/tty2 c 4 2
mknod -m 666 ${dev_path}/tty3 c 4 3
mknod -m 666 ${dev_path}/tty4 c 4 4
mknod -m 600 ${dev_path}/console c 5 1
mknod -m 666 ${dev_path}/full c 1 7
mknod -m 600 ${dev_path}/initctl p
mknod -m 666 ${dev_path}/ptmx c 5 2

echo "Creating network config eth0"
cat <<EOF > ${rootfs}/etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
TYPE=Ethernet
USERCTL=yes
PEERDNS=yes
IPV6INIT=no
EOF

echo "Creating network config resolv.conf"
cat > $rootfs/etc/resolv.conf << END
# Google public DNS
nameserver 8.8.8.8
nameserver 8.8.4.4
END

echo "Creating network config sysconfig/network"
# set the hostname
cat <<EOF > ${rootfs}/etc/sysconfig/network
NETWORKING=yes
HOSTNAME=${name}
EOF

echo "Creating config fstab"
# 
cat <<EOF > ${rootfs}/etc/fstab
none /dev/pts devpts defaults 0 0
none /proc    proc   defaults 0 0
none /sys     sysfs  defaults 0 0
none /dev/shm tmpfs  defaults 0 0
EOF
 
echo "Creating etc/hosts"
# set minimal hosts
cat <<EOF > $rootfs/etc/hosts
127.0.0.1 localhost $name
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
EOF

# selinux
echo "Creating selinux"
cat <<EOF > $rootfs/etc/selinux/config
SELINUX=disabled
SELINUXTYPE=targeted 
EOF

#
echo "Creating init for guest"
cat <<EOF > $rootfs/bin/lxc_guest_init.sh
#!/bin/bash 
export PATH=$PATH:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
export PS1="[\u@\h \W]\\$ "

mount -t devtmpfs none /dev
mount -t devpts none /dev/pts
mount -t tmpfs none /dev/shm

/etc/init.d/network start
/etc/init.d/sshd start

exec /bin/bash
EOF
chmod 755 "$rootfs/bin/lxc_guest_init.sh"

# 
echo "Setting up sshd_config"
sed -i 's/^UsePAM\ *yes/\#&/' ${rootfs}/etc/ssh/sshd_config
sed -i 's/^GSSAPIAuthentication\ *yes/\#&/' ${rootfs}/etc/ssh/sshd_config
echo "pts/0" >> /etc/securetty

#
echo "Setting up etc/environment"
cat >> $rootfs/etc/environment <<EOM
LANG="en_US.UTF-8"
LANGUAGE="en_US:en"
PS1="[\u@\h \W]\\$ "
EOM
cat > $roofs/etc/default/locale <<EOM
LANG="en_US.UTF-8"
LANGUAGE="en_US:en"
EOM


# libvirt.xml
echo "Creating libvirt config: $libvirt_xml"
cat <<EOF > $libvirt_xml
<domain type="lxc">
  <name>$name</name>
  <memory>102400</memory>
  <os>
    <type>exe</type>
    <init>/bin/lxc_guest_init.sh</init>
  </os>
  <vcpu>1</vcpu>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/libvirt_lxc</emulator>

    <filesystem type="mount">
      <source dir="$rootfs/bin/"></source>
      <target dir="/bin">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/etc/"></source>
      <target dir="/etc">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/lib/"></source>
      <target dir="/lib">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/lib64/"></source>
      <target dir="/lib64">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/mnt/"></source>
      <target dir="/mnt">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/sbin/"></source>
      <target dir="/sbin">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/selinux/"></source>
      <target dir="/selinux">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/usr/"></source>
      <target dir="/usr">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/home/"></source>
      <target dir="/home">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/root/"></source>
      <target dir="/root">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/media/"></source>
      <target dir="/media">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/dev/"></source>
      <target dir="/dev">
    </target></filesystem>

    <filesystem type="mount">
      <source dir="$rootfs/var/"></source>
      <target dir="/var">
    </target></filesystem>

    <interface type="network">
      <source network="default"></source>
    </interface>
    <console type="pty">
  </console></devices>
</domain>
EOF

echo
echo "Done."