Difference between revisions of "Diskless netboot"
 
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Diskless server / workstation using netboot
+
[[Category:Linux]]
  
  
−
NFS is a technology that allow you to share some files and folders over the network. So:
+
==Target folder tree (server side)==
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* All the clients will share the installation, configuration files and so on.
 
−
* Each client will run a dedicated instance of the operating system
 
−
* Logs will be centralized on the common NFS server - so we don't loose data on each reboot.
 
  
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You must have a working DHCP server + NetBoot before starting this part.
+
This is how we'll setup our files and folders:
  
 +
<syntaxhighlight lang="bash">
 +
# 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
  
−
Requirements:
+
/tftpboot/images/     
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* [[DHCP server]]
 
−
* [[NetBoot server]]
 
  
 +
# 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
  
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=Installation=
 
  
 +
#### NFS
 +
# This is where the runnable will be. Each image will be in a dedicated folder.
 +
/nfs/                   
  
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'''NFS support'''
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# Debian 7.x [Wheezy]
−
<syntaxhighlight lang="bash">
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/nfs/wheezy/ 
−
apt-get install nfs-kernel-server nfs-common
+
 
 +
# Ubuntu 14.04 [Trusty]
 +
/nfs/trusty/
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
'''Debootstrap (manage netboot image)'''
+
 
 +
 
 +
==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:
 +
 
 +
[[File:Client_composition.png|480px|NetBoot client RAM overview - 4Go]]
 +
 
 +
 
 +
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:
 +
 
 +
[[File:Client_mount_points_2Go.png|480px|NetBoot client RAM overview - 2Go]]
 +
 
 +
 
 +
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:
 +
 
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
−
apt-get install debootstrap
+
mkdir -p /nfs/trusty
 +
mkdir -p /nfs/wheezy
 +
mkdir -p /nfs/common
 
</syntaxhighlight>
 
</syntaxhighlight>
  
  
 +
- NOTES -
  
−
=NFS server setup=
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* 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
  
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==Preparation==
 
  
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You have to create a dedicated folder on your server where you will host the client image.
 
  
−
<syntaxhighlight lang="bash">
+
==Configure client distribution==
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mkdir -p /srv/nfsroot
+
 
−
</syntaxhighlight>
+
* 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.
  
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==Configuration==
 
  
−
The NFS configuration is done in the '''/etc/exports''' file
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===Compression===
  
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
−
vim /etc/exports
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cd /nfs
 +
tar cvpjf trusty.tar.bz2 ./trusty
 
</syntaxhighlight>
 
</syntaxhighlight>
  
  
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Add something like that:
+
===Restoration===
  
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
−
  /srv/nfsroot      192.168.2.xxx(rw,no_root_squash,async,insecure)
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cd /nfs
 +
tar -xvjf trusty.tar.bz2
 
</syntaxhighlight>
 
</syntaxhighlight>
  
 +
=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
  
−
Adjust "192.168.2.xxx" to your own network address
 
  
 +
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/
  
−
==Security==
 
  
−
Like TFTP, this part is insecure !
+
Nice explanation of PXE process: http://www.linux.com/learn/docs/ldp/497-Diskless-root-NFS-HOWTO
  
−
You must restrict the access to your NFS server by a firewall script and filtering BEFORE reaching the LAN !
+
* How to improved /etc/fstab: http://www.askapache.com/optimize/super-speed-secrets.html

Latest revision as of 15:37, 21 August 2014


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:

NetBoot client RAM overview - 4Go


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:

NetBoot client RAM overview - 2Go


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



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:



Local server monitoring

Install the following services:



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:


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

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