System Installation Suite

Who Am I

– Linux and Open Source Consultant

– „Infrastructure Architect“

– Linux since 0.98

– IANAKH

– Senior Consultant/CTO @ x-tend.be

WARNING

Or Credits ;)

Sean Dague : OLS2002 Talk

Thomas Lange : Fai talk at UKUUG 2005

Own previous talks

infrastructures.org

Today:

– Automating Machine Installs

– Reproducable

– Distro Independent

– FAST

– No Vendor Lock In!

–

Common Problems

• Accidental Identical Installs

• Many manual changes to systems

• Many undocumented changes

• Emergency Administration only

• Computers don’t work hard enough for us

•

Investing in Automation

• How long does it take to reinstall a machine

from 0

• To the exact same point as before ?

• With different Hardware ?

• What about customer/personal data ?

Facts!• Data Backup is only a part

• Sysadmin backup needs to be done also

• Manual Installations = bad

• Bad installations = unusable infrastructure

• Manual efforts = no time

• Bad installations = unproductive users

• Bad installations= manual efforts

• No time = no updates no patches no security

• Manual work = high costs

Do you want to ? (2)• Install the previous racks manually

• Over and over again ?

• And can you guarantee that installs are identical ?

• Sysadmins are Lazy (by default)

•

Do you want to ? (3)• “No simple admin taks is fun more than twice”

• s/twice/once/g;

• Repeating installs are boring and prone to errors

• Each installation is unintentionally Unique

• Manual installs DO NOT scale

Planning your infrastructure(s.org)

• Look at the infrastructure, not at 1 machine

• Plan changes in advance

• Version Control !

• {SystemAdminstration,Security} is a process, not a product, or even a LifeStyle

• Look for Similarities

• And differences

The 10th floor test

• Grab a random machine (don’t take a backup before)

• Throw it out a 10th floor window

• Can you recover it in 10 minutes ?

Imaging vs InstallingImaging

- Speed

- Identical machines

- Multicasting

Installing

- Finegrained

- “slower”

- Then install the delta's

Imaging Stinks ?

“Imaging sucks unless you create your image

with FAI”

Thomas Lange (FAI Presentation UKUUG 2005)

Sisuite History• Spring 2000 , SF Was just announced by VA Linux , RH 6.2 , Xfree86 4.0

• Not many clusters (no Scyld Beowulf 2 yet)

• RedHat had kickstart

• IBM: Lui Linux Utility For Cluster Installation (v1.0 April 200)

– Rich Ferri , IBM

– RH Only

• SystemImager v1.0 (May 2000)

– Brian Finley, VA Linux System

– Redhat and Debian only

Systemimager Suite: systemimager● Image Base

● Captures Images from a golden client

● All images stored on a central server

● Image is a complete copy of all disks on client

● Linuxbased autoinstall system

● Install from Floppy, CD, Harddrive or Network

SystemImager Suite (2)

● SystemInstaller

● Evolved from LUI

● Generates Images based on

● Packagelist

● Distro type

● Partition Definition

`SystemImager Suite (3)

● SystemConfigurator

● Post install configuration

● Hardware detection / bootloader config

● Distro integration

Systemimager Suite: overview●

SIS Image

• A Directory that contains the entire contents of the filesystems of a live

machines

• Stored in /var/lib/systemimager/images/$NAME

• Exported as an rsync module $NAME

• You can chroot into it

• Not as unchangeable as other imaging tools

Fetching an Image

• Install golden client as you would install any other server

• Install systemimager_client on that machine

• Prepare client

– Run si_prepareclient

– Captures all partition info in to /etc/systemimager/

– Starts rsync daemon as rsync module “root”

• Capture Image from server

– Run si_getimage

– Connects via rsync to rsync://golden-client/root and transfers to

/var/lib/systemimager/images/$imagename

– Calls mkautoinstallscript to build the autoinstallscript

My Advise: this is not the way!

• Perfect for Quick and Dirty backups

• Disaster recovery for single image setups

!! Don’t build your infrastructure on this method !!

• Reproducability is low

• Package management is better these days.

• Minimal changes in chroot are still undocumented and error prone

•si_mksiimage

•Takes parameters such as

• Packages list

•Partition list

•Determines the distribution based on the packages

•Determines”best” version to install of a package (version/architecture)

•Issues:

•Keep track of every distro ?

•Staged installes ?

•Ordering ?

•Post installscripts fail in chroot

Building an Image

– Yum –installroot=/path/ -y groupinstall Base

– Debootstrap

– Urpmi –root=/path basesystem urpmi ssh-server

– Yast

– Rpmstrap

Building an Image in 2005

Other Clues

• Mksidisk

• Addclients

• Mksimachine

• Mksirange

(haven’t used them lately might have si_ prepended these days)

Boel

• Autoinstall is driven by Brian’s Own Embedded Linux

– Special kernel and ramdisk

– Boots from floppy,cd, harddrive or pxe

– Kernel + initrd

– Tarbal with busybox, extra modules , other tools are being

rsynced over the network

Image Server

• SystemImager repository in var/lib/systemimager

– images/images

– overrides/hostname : configfiles per host containing network and

hardware configs and custom scripts

– scripts/ the actual machine dependent install scripts with partition

information etc.

Image server (2)

• DHCP Server

• PXE Boot environment

• /usr/share/systemimager Boel environment (mini embedded

environment)

• Rsync server

Bootstrap Procedure• Create a dhcp config file with the appropriate entries

• Machine PXE Boots over the network and downloads the initial kernel

and initrd

• Creates an initial ramdisk and asks ip addres, hostinfo, and in-

stallserver information.

• download boel image and setup a minimal environment (rsync)

• Based on the hostinfo downloads the host specific script (autoin-

stallscript) (hostnameXY.(sh/master))

AutoInstallScript• Partition the harddisk

• create the filesystems

• mount them

• rsync the $image to the harddisk.

• Run systemconfigurator

• Run postinstall script

• Reboot

Systemconfigurator• Problem:

– Network configs

– Hardware config

– Bootloader

• Solution ?

– Build a huge matrix

• Unmaintainable

– Footprinting detect similar configs

• If /etc/sysconfig/network-scripts then create ifcfg-$ETH

• If /sbin/lilo and /etc/lilo.conf exist then configure lilo

Systemconfigurator• Further problems

– Uses perl

– Can grow big

– Needs other tools

– ==> Chroot into the freshly installed system

• Modular approach

– --confighw , --confignet , --configrd , --configboot , --runboot etc

– Or combinations –configsi == --confighw –confignet –runboot

Image Maintenance

• Updateclient

• Please don’t

• Use package management tools

•

Misc Facts and Figures

• OSCAR : Uses SIS

• Installs as fast as < 4 minutes

• Flamethrower adds multicast features

• Xen integration

Alternative Tools !

• Commercial :

• RedHat Network : Satellite

• Novell Zenworks

• Open Source

• Fai

Links

• http://sisuite.org/

• http://wiki.sisuite.org

•

• http://planet.grep.be/

? !• Questions ?