Diskless netboot

Target folder tree (server side)

This is how we'll setup our files and folders:

# TFTP root
/tftpboot/                                   

###############
# Network bootable image(s) using NFS technology
################       

#### Boot file            
/tftpboot/pxelinux.0                   # Initial boot file - only use to load the PXE NetBoot manager
/tftpboot/{menu.c32 || vesamenu.c32}   # PXE interactive menu managers (text or graphical)
/tftpboot/pxelinux.cfg/                # PXE configuration(s)
/tftpboot/pxelinux.cfg/default         # default PXE configuration

#### Kernel file

/tftpboot/images/      

# Debian 7.x [Wheezy] 
/tftpboot/images/wheezy/   
/tftpboot/images/wheezy/vmlinuz
/tftpboot/images/wheezy/initrd.img

# [X]Ubuntu 14.04 [Trusty] 
/tftpboot/images/trusty/  
/tftpboot/images/trusty/vmlinuz
/tftpboot/images/trusty/initrd.img


#### NFS 
# This is where the runnable will be. Each image will be in a dedicated folder.
/nfs/                    

# Debian 7.x [Wheezy] 
/nfs/wheezy/   

# Ubuntu 14.04 [Trusty] 
/nfs/trusty/

Client overview

Each client must have, at least, 4 Go of RAM.

4 GO RAM configuration

This is how we're gonna populate the client:

As you can see, each client will have some space dedicated for swap + some RAMdisk to allow writing in /var, /tmp and /proc.

Configuration of a 4Go RAM disk:

• No swap
• Local TMPFS (read/write for /dev, /tmp, ...) : 1 Go
  • /tmp = 512 M
  • /var/tmp = 128 M
  • /var/log = 128 M
  • /var/run = 8 M
  • /var/lock = 8 M
  • /run/shm = 256 M
• O.S (NFS read only) : all the rest ~ 2.8 Go
• Common share (NFS read write) : Remote disk

2 Go

Due to budget restriction we might encounter some low memory machines with only 2 Go...

This is how we're gonna populate the client:

In case of 2Go RAM then you have to use some tricks:

• No swap
• O.S (NFS read only) : ~ 1.2 Go
• Common share (NFS read write) : Remote disk
• Local TMPFS (read/write for /dev, /tmp, ...) : all the rest
  • /tmp = 372 M
  • /var/tmp = auto
  • /var/log = 128 M
  • /var/run = auto
  • /var/lock = auto
  • /run/shm = auto

How big is the client image ?

By default the deboostrap Ubuntu 14.04 LTS image is 239 Mo. With the applications we're gonna use that size will increase to about 1 or 1.3 Go depending if you copy (or not) the kernel sources. It may even take 1.6 Go if you're using XFCE frontend.

NFS client image

There are different way to setup a NFS client image.

The main ones are:

• Manually
  • debootstrap
  • copying the install from your server
  • Manual install on a client, then, when the system is ready, copy everything to the NFS share

• Using script and software like "Puppet" or "Chef"

Setup client distribution

You have to create one target for each distribution you want to serve:

mkdir -p /nfs/trusty
mkdir -p /nfs/wheezy
mkdir -p /nfs/common

- NOTES -

• The folder name should match your NetBoot settings. Folder name = a LABEL in the NetBoot config.

• The folder name should match a Linux (Debian like) distribution name

Configure client distribution

• Manual configuration: Diskless image configuration - manual setup

• Automatic [Puppet || Chef] configuration: Diskless image configuration - script setup

Backup distribution

You can create an archive of your current distribution for later restore / re-use.

Compression

cd /nfs
tar cvpjf trusty.tar.bz2 ./trusty

Restoration

cd /nfs
tar -xvjf trusty.tar.bz2

PXE interactive menu

You can create interactive NetBoot menus, see:

• PXE interactive menu - single level
• PXE interactive menu - multi level

Local server monitoring

Install the following services:

• SNMP client
• Zabbix agent setup

Other services

File sharing

If you want to expose the NFS common folder as a file-share, you have to install and configure Samba. See: Samba server

Note

Samba is actually better than NFS for the file-share. You should remove Common from /etc/exports and use a samba share instead.

Management UI (webmin)

Since there is a lot of services to manage, it's always convenient to use an UI for it. Check Webmin

VPN server

See VPN

Apache2 server

See Apache 2

References

Ubuntu diskless how-to: https://help.ubuntu.com/community/DisklessUbuntuHowto

Mind reference: http://mindref.blogspot.se/2011/03/debian-diskless.html

Super video tutorials:

• https://www.youtube.com/watch?v=js9imsrqAMk
• http://www.stepladder-it.com/bivblog/14/ to /16/
• https://blog.dlasley.net/2013/01/pxe-server-ubuntu/

Nice explanation of PXE process: http://www.linux.com/learn/docs/ldp/497-Diskless-root-NFS-HOWTO

• How to improved /etc/fstab: http://www.askapache.com/optimize/super-speed-secrets.html