In this post I will demonstrate how to use febootstrap to make a root file system (rootfs) for a LXC container using Fedora. This technique is working with Fedora 12 and rawhide. Rawhide is under development and will become Fedora 13, so use a rawhide container at your own risk.

Most of the commands in this tutorial are run as root. To obtain a root shell use:

su -

The working directory for this tutorial is /home/bodhi/lxc , so config.fedora and rootfs.fedora are both located in /home/bodhi/lxc

Note: Unless you are familiar with selinux, it may be helpful to disable selinux as you learn to use Linux Containers.

setenforce 0

Make a rootfs via febootstrap

# Fedora 12
febootstrap fedora-12 rootfs.fedora

# Rawhide
febootstrap rawhide rootfs.fedora

Configure the rootfs

Copy resolv.conf from host node to container

cp /etc/resolv.conf rootfs.fedora/etc

Fix devices

udev does not run in lxc containers, so you need to manually make the needed devices.

I use this script to configure the devices:

#!/bin/bash

# bodhi.zazen's lxc-config
# Makes default devices needed in lxc containers
# modified from http://lxc.teegra.net/

ROOT=$(pwd)
DEV=${ROOT}/dev
if [ $ROOT = '/' ]; then
printf "\033[22;35m\nDO NOT RUN ON THE HOST NODE\n\n"
tput sgr0
exit 1
fi
if [ ! -d $DEV ]; then
printf "\033[01;33m\nRun this script in rootfs\n\n"
tput sgr0
exit 1
fi
rm -rf ${DEV}
mkdir ${DEV}
mknod -m 666 ${DEV}/null c 1 3
mknod -m 666 ${DEV}/zero c 1 5
mknod -m 666 ${DEV}/random c 1 8
mknod -m 666 ${DEV}/urandom c 1 9
mkdir -m 755 ${DEV}/pts
mkdir -m 1777 ${DEV}/shm
mknod -m 666 ${DEV}/tty c 5 0
mknod -m 666 ${DEV}/tty0 c 4 0
mknod -m 666 ${DEV}/tty1 c 4 1
mknod -m 666 ${DEV}/tty2 c 4 2
mknod -m 666 ${DEV}/tty3 c 4 3
mknod -m 666 ${DEV}/tty4 c 4 4
mknod -m 600 ${DEV}/console c 5 1
mknod -m 666 ${DEV}/full c 1 7
mknod -m 600 ${DEV}/initctl p
mknod -m 666 ${DEV}/ptmx c 5 2

exit 0

The script is very slightly modified from This page and is saved in /usr/local/bin/lxc-config .

Make it executable :

chmod u+x /usr/local/bin/lxc-config

Run the script in rootfs.fedora

cd rootfs.fedora
/usr/local/bin/lxc-config # fix /dev

Generate a config file

I call it config.fedora . Make sure the following information is accurate:

container name (lxc.utsname)
network (lxc.network.ipv4)
rootfs (lxc.rootfs)

lxc.utsname = fedora
lxc.tty = 4
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br0
lxc.network.name = eth0
lxc.network.mtu = 1500
lxc.network.ipv4 = 192.168.0.0/24
lxc.rootfs = /home/bodhi/lxc/rootfs.fedora
lxc.cgroup.devices.deny = a
# /dev/null and zero
lxc.cgroup.devices.allow = c 1:3 rwm
lxc.cgroup.devices.allow = c 1:5 rwm
# consoles
lxc.cgroup.devices.allow = c 5:1 rwm
lxc.cgroup.devices.allow = c 5:0 rwm
lxc.cgroup.devices.allow = c 4:0 rwm
lxc.cgroup.devices.allow = c 4:1 rwm
# /dev/{,u}random
lxc.cgroup.devices.allow = c 1:9 rwm
lxc.cgroup.devices.allow = c 1:8 rwm
# /dev/pts/* - pts namespaces are "coming soon"
lxc.cgroup.devices.allow = c 136:* rwm
lxc.cgroup.devices.allow = c 5:2 rwm
# rtc
lxc.cgroup.devices.allow = c 254:0 rwm

Fix rootfs

touch rootfs.fedora/var/run/syslogd.pid
mkdir -p rootfs.fedora/var/lock/subsys
touch rootfs.fedora/var/lock/subsys/{atd,ip6tables,iptables,local,network,rsyslogd,sshd}

Disable udev

rm rootfs.fedora/etc/init.d/udev-post

edit rootfs.fedora/etc/rc.sysinit and comment out the start_udev line

# /sbin/start_udev

Set up fstab and mtab

touch rootfs.fedora/etc/{fstab,mtab}
echo "none /dev/pts devpts defaults 0 0" >> rootfs.fedora/etc/fstab

Configure networking

eth0

Using any editor, edit rootfs.fedora/etc/sysconfig/networking-scripts/ifcfg-eth0

set your ipaddress in this file, either via static or dhcp (I use static IP)

DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
HOSTNAME=fedora
TYPE=Ethernet
IPADDR=192.168.0.20
NETWORK=192.168.0.0
GATEWAY=192.168.0.1
BROADCAST=192.168.0.255
NETMASK=255.255.255.0
MTU=1500
DNS1=192.168.0.1
IPV6INIT=no
USERCTL=no

Using any editor, edit rootfs/etc/sysconfig/network

Add these two lines (adjust hostname):

NETWORKING=yes
HOSTNAME=fedora

Using any editor, edit rootfs/etc/rc.local

Add (was necessary to bring up the network in my Fedora containers).

service network restart

Remove tty5 and tty6

Fedora 12

cd rootfs.fedora/etc/event.d
rm tty{5,6}

Radhide: edit rootfs.fedora/etc/sysconfig/init

The very last line of the file reads "ACTIVE_CONSOLES=/dev/tty[1-6]" , change this to

ACTIVE_CONSOLES=/dev/tty[1-4]

Chroot and set a root password

chroot rootfs.fedora /bin/bash
passwd

Configure and start the container

lxc-create -f ~bodhi/lxc/config.fedora -n fedora

Disable selinux (on the host

setenforce 0

Start the container, watch for error messages

lxc-start -n fedora

Note: It takes some time for the container to boot ...

lxc-console or ssh in and set a locale

lxc-console -n fedora

In the container run:

yum -y reinstall glibc-common

#auditd is not woking, so turn it off
chkconfig auditd off

#sendmail is slow to start, so if you are not using it disable it
chkconfig sendmail off

Clean up container

From within the container

yum clean all

Stop the container

lxc-stop -n fedora

Optional : Clean unnecessary files

remove the febootstrap cache (if it exists). You may remove the shared doc and locales.

rm -rf rootfs/var/yum/cache/febootstrap
rm -rf rootfs/usr/share/locale/*
rm -rf rootfs/usr/share/doc/*