cloning windows nt systems mainly based on experiences at ral and oxford
TRANSCRIPT
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.