Diskless image configuration - manual setup

This article explains how to setup MANUALLY a netboot image.

Instead of manual operations you can use some config managers such as Puppet or Chef.

Get distribution's content

Debian 7.x

cd /nfs/wheezy
debootstrap wheezy /nfs/wheezy

Ubuntu 14.04

cd /nfs/trusty
debootstrap trusty /nfs/trusty

Access distribution

This will "mount" the system:

# Debian 7.x
chroot /nfs/wheezy/

# Ubuntu 14.04
chroot /nfs/trusty/

From here you can perform operation as if you were on a separate machine.

Only the current distribution (= the client one) will be affected.

Setup

Adjust default login/password

First of all, you have to create / adjust the default user.

# Add new user
adduser <username>
# Add user to sudoers group
usermod -a -G sudo <username>

Now you can use that user:

su <username>
sudo -s

You can check that you really are in the "Virtual machine" by checking "/srv/". It should be empty !

- Note -

On Debian distribution you have to install "sudo" manually. It's not in the defaults packages.

Update sources.list and install key packages

Your client need to have some key packages in order to work. Without these package even the NetBoot will fail !!

First of all: edit your sources.list

apt-get install vim
vim /etc/apt/sources.list

Put the following:

### Custom repositories list
#
# May 2014 - Guillaume Diaz
# This is an ajdustement of the default "debootstrap" sources.list
# This is required to provided update, security and advanced tools to all our clients
#

# Official repositories
deb http://se.archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://se.archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu trusty-security main restricted universe multiverse

# Official updates 
deb http://se.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse

# Canonical partners
#deb http://archive.canonical.com/ubuntu trusty partner

# Community partners
#deb http://extras.ubuntu.com/ubuntu trusty main

Update your package list:

apt-get update && apt-get upgrade

Now, you can install the basic programs:

# NFS client. This is ABSOLUTELY MANDATORY ! That's the only way to mount the /root
apt-get install nfs-common
apt-get install initramfs-tools

# NFS is a bit low, and if you're using many client it might result in time faults. 
# You must install NTP to overcome this !!
apt-get install ntp ntpdate

# Basic set of utilities
apt-get install unzip zip
apt-get install make autoconf automake cpp gcc build-essential
apt-get install htop
apt-get install python3

# Advanced APT manager (require to add repository from command line)
apt-get install software-properties-common python-software-properties


# JAVA (that is required for my application)
# Depending on your target usage you might not need it.
add-apt-repository ppa:webupd8team/java 
apt-get update && apt-get upgrade
apt-get install oracle-java7-installer oracle-jdk7-installer

Adjust bash and vim configuration

Edit your VIM configuration:

vim /etc/vim/vimrc

Enable dark background + set nu + set ruler

Edit your bash configuration files to adjust the alias and enable auto-completion:

vim /etc/bash.bashrc
vim /home/<username>/.bashrc
vim /root/.bashrc

Install a local kernel

--- TO BE CHECKED --- IS IT MANDATORY ??

To install a local kernel, you have to:

• mount /proc
• unpack linux-headers-generic
• unpack linux-image-generic

mount /proc
apt-get install -y linux-headers-generic
apt-get install -y linux-image-generic

Check that you have some symlinks in /, either create them:

ln -s /boot/vmlinuz-3.5.0-21-generic /vmlinuz         
ln -s /boot/initrd.img-3.5.0-21-generic /initrd.img

!! Don't forget to adjust the number to your actual version !!

Edit mount points (/etc/fstab)

You must edit the mount points to get the client working!

vim /etc/fstab

/proc    /proc    proc    defaults   0 0
/sys     /sys     sysfs   defaults   0 0
/dev/nfs /        nfs     defaults   1 1

Adjust network configuration

Up to this point the client will already have got a DHCP address through the NetBoot process.

Therefore, you should prevent users / services from changing that automatic configuration.

Edit the config file:

vim /etc/network/interfaces

Put:

## Manual override of the debootstrap shipped configuration
#
# Version 1.0 - May 2014 - Guillaume Diaz
#

# Loopback
auto lo
iface lo inet loopback

# Keep the NetBoot configuration
iface eth0 inet manual

# Intel NUC trick - as the NUC uses "em1" instead of "eth0"
iface em1 inet manual

Run clients in diskless NFS mode

Now you are (finally) ready to tell the client to run in diskless mode! Edit the config file:

vim /etc/initramfs-tools/initramfs.conf

Set the following values:

MODULES = netboot 
BOOT    = nfs

Apply changes:

update-initramfs -u

Exit client distro

umount /proc
exit

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