Cloning Windows NT Systems

Mainly based on experiences at RAL and Oxford.

Windows NT at RAL

• Office systems NT based.• Use Exchange server / Outlook 98.• Client for financial system on NT.• SMS used centrally to upgrade some 570 PCs.

(E.g. NT 3.51 -> 4 and Office 95 -> 97 upgrades.)

• Some services on NT (databases, dial-in, DHCP)

• NT farm for HEP use.

Windows NT in RAL Particle Physics

Department

Windows NT on Desktop. Access to Unix, VMS servers via X

(Exceed).

• Two main servers: One Intel, One Alpha.

• Desktop (Intel) systems cloned.– Buy PCs in batches - not all identical.

Topics Covered

• Design Goals for Desktop Systems.• Methods of Cloning.• Issues in cloning applications.• Experiences.• Disadvantages / Advantages of

cloning.• Laptops.

Issues / Goals for Desktop Systems

• Minimise Support Effort & Cost• Setup a good environment for the user

– e.g. sensible defaults• Systems (sufficiently) similar a user can move

between them and still see the same environment. – Can replace system in event of ‘failure’.

• Users’ files (including configuration files etc.) stored on server.

Specific Examples...

• Storing a users configuration for the application back on the server (e.g. Netscape bookmarks)

• Default location for saving files to be on the server not the local hard disk of the PC.

• No backups made of desktop systems.

What methods are there for setting up NT?

• Separate installs on each PC• Use SMS• Some form of duplication of a

‘master’ setup:– NICE– Simple cloning

• Zero Admin Windows

Methods of Cloning

• NT Install/Backup

• Disk Imaging (Ghost, DriveImage)

• SYSDIFF

Using NT Install/Backup

• On Master System– Backup the registries (to files).– Make a Backup.

• On Target System– Install NT to same level as Master(install options, network setup, service pack)– Backup (overwrite) from Master– Replace software & default registry hives– Patch-up

Disk Imaging

• Various commercial products available.– Ghost from Norton.– DriveImage from Powerquest.

• Make image of master system’s disk. (Place on server) and load down onto target machines.

• Some patch-up needed:– Load any different drivers (video and network cards) – Modify name & IP address.– Use SID changer.

SYSDIFF

• Resource kit utility.• Snapshot systems (registry and

files).• Records differences since a

snapshot and can apply those differences to another system.

• Problems with NT service packs.

Some issues in cloning an application.

Application made up of:• Executable Files etc.• Initialisation/Configuration Files (initial &

modified)– Per machine– Per user

• Registry Settings (initial & modified)– Per machine (HKEY_LOCAL_MACHINE)– Per User (HKEY_CURRENT_USER)

Where do these come from?

• Executable Files Application install• Ini. /Conf. Files

– Per machine Application install– Per user Application install

• Registry Settings– Per machine (HKLM) Application

install– Per User (HKCU) Application install

Where do these come fromon a cloned system?

• Executable Files cloning• Ini. /Conf. Files

– Per machine cloning– Per user copy in (at login)

• Registry Settings– Per machine (HKLM) cloning– Per User (HKCU) copy in (at login)

Experience with Cloning (1)

Oxford University Physics Department

• Use Ghost.• Approaching 200 systems

supported• Update ‘on demand’• Some tidy-up via nightly batch job.

Experience with Cloning (2)

RAL• Use of Install/backup works. (Approximately 50

systems installed.)• However, rather too heavy for updating regularly.

– Moving to using DriveImage and SYSDIFF.

• Problems with large packages required by a smaller number of users. Solution:– Install onto server– Control access via ACLs.

Disadvantages

• Updating of cloned systems from time to time.Not suitable as it stands for very large sites.

• If a user adds their own software to ‘their’ system this may be ‘lost’ during an upgrade.

• All applications distributed to all systems. (May need to buy ‘unnecessary’ licenses.)

• Can we have problems with different hardware in PCs that is not handled correctly by cloning?

• (Not the same setup as elsewhere at RAL.)

Advantages

• Easy to build/rebuild systems– No need to backup workstation disks– Simple route to recover from problems

• Same set of applications everywhere.• Study how to setup an application once, then duplicate.• Can setup applications such that

– Users have their own configurations that move with them.

– Novice users find sensible defaults.

=> Lower maintenance overheads.…

LAPTOPS

• Problems Cloning to Laptops:– Hardware very different to desktop systems.– Model of ‘standard system’ does not apply:

• Cannot have all configuration files etc. on server.• Systems personalised - difficult to update by

overwriting.• SYSDIFF offers method of applying/updating

applications.

– If share environment with desktops, important to choose carefully which applications are server-based.

Summary

• Cloning works for a moderate size department ( <100? )

• If you have a reasonable set of applications, many users content.

• Comprises a set of simple tools that interwork.

• Benefits from knowing setup the same on all systems.