COMP3122 Network Management

COMP3122 Network Management Richard Henson March 2011

Week 6 – Installing & Auto-installing software • Objectives • Explain different methods for installing system and application software on client machines • Explain how installation can occur without user intervention • Explain how a complete system can be rapidly installed on a client machine to minimise downtime

Serving Users • What happens at the server end is mostly “behind the scenes” • users rarely get involved… • Client-end matters are often “up-close-and-personal” • client machines in the hands of users • users not able to do their job because something isn’t working as they would wish can be difficult to deal with

Managing Clients • One of the most important parts of the job of a network manager • potentially more troublesome as the network gets bigger and more diverse • Having “happy” users involves getting three things right: • user and group settings • applications delivered via the desktop • desktop settings

Client Installation Methods: Sequence of Operations • Applications run on operating systems • makes sense to install the operating system first • some methods (e.g. disk “imaging”) do both simultaneously

Client Installation Methods: 1. From Local CD-ROM • Software issued by suppliers on CD-ROM or DVD-ROM • could just install operating systems and applications to individual machines via CD-ROM drive on the client machine • Problem… TIME! CD-ROM slow • modern systems software and applications are EACH often large (> 500 Mb) • long time to copy CD -> hard disk • replicated many times to install all this on all machines in a typical network

Client Installation Methods: 2. from local hard disk • Convenient if operating system already installed • applications all copied “en bloc” from CD-ROM to local hard disk (may need a large hard disk…) • technician can get on with other tasks while the apps installation files are copying • Installation program then executed directly from local hard disk • rapid copying because no CD-ROM involved • significantly faster than CD-ROM based installation

Client Installation Methods:3. CD-ROM across the network • CD-ROM drive on the server • Local machine accessible from the server • Either: • contents of CD-ROM copied across the network to local hard disk (slow) • software then installed from local machine (faster) • Or: • Software installed directly to local machine from network CD-ROM (slow)

Client Installation Methods:4. USB across the network • Assumes previous copying of app(s) to USB: • memory stick then plugged into USB the server • Either: • USB data copied across the network to local hard disk (fast) • then software installed from local machine (fast) • Or: • software installed directly to local machine from network CD-ROM (fast)

Client Installation Methods: 5. Directly from Server Hard Disk across the network • Software all previously copied to server hard disk (CD-slow, USB-faster) • Then either: • data copied across the network to local hard disk (fast) • software then installed from local machine (fast) • Or: • Software installed directly to local machine from network server (fast)

Client Installation Methods: 6. To multiple clients simultaneously from Server • Software all previously copied to server hard disk as before (CD-slow, USB-faster) • data copied simultaneously across the network to many local hard disks (slow) • apps then triggered to install “unattended” on local machine (fast)

Unattended Installations • Whilst software is being installed on a computer, the set-up program asks a series of questions… • means that the installation cannot be fully automatic • However, for a given hardware setup it is possible to create and use a text file containing appropriate answers to the set-up program’s questions • the set-up program processes these directly • fully automated installations then occur…

Managing Unattended Installations across the network • “Batch file” written to answer set-up program all these questions automatically • accessible to all “hardware clone” clients from the server • With Windows 2000 etc., batch file saved as UNATTEND.TXT • to take account of the different hardware specifications of client machines, a number of “unattend” files need to be available on the server

“Batch” or “Script” files • Just a series of commands for the operating system e.g. • Autoexec.bat (from MS-DOS) • Win.ini (from Windows 3.1) • Unix “shell scripts” • All commands executed automatically, and very quickly, without user intervention

Creating the scripts for an unattended installation • At first sight, two alternatives: • EITHER • created manually, from knowledge of the setup program, and the information it would request • perhaps with the help of template files… • OR • created automatically with software as a result of checking the system configuration of a machine that has already been set up

Creating a system for unattended installations on clients • A very clever system could do it all… • check any client computer to be used on the network • make note of the drivers, settings, etc. • use this information to generate a script • store the script on a network server • allow access to the script across the network • execute the script whenever a similar installation is to occur on a similar type of machine

Starting Computers Remotely (Remote boot motherboard) • Motherboards now have a program in the BIOS settings (PXE-BIOS) that can be activated remotely to start the boot-up process • Requires client to be already switched on and connected via network to server… • very useful, and greatly labour saving! • can be used to activate a client machine at some distance from the server remotely so that software can be installed

Remote Installation “from scratch” on a new client • Client with PXE-BIOS needs to be able to boot up… • by accessing, downloading, and executing an operating system boot program remotely across the network • which will then trigger the operating system remote install… • Whichever system is used the operating system needs to be available from hard disk on a network server…

Remote booting an older BIOS • Older machines do not have motherboards that support the PXE remote boot environment • However, a tool is available with Windows servers that enables remote booting on a non-PXE motherboard • such a useful thing to be able to do! • means that any clients, no matter what the age of the motherboard, can always be remotely configured

Upgrades to Operating Systems and Applications • Upgrading an operating system across a network is a major undertaking • carefully planning! • all data needs to be backed up • applications may need to be reinstalled • sometimes quicker to start again from scratch than go through the lengthy upgrade process… • Upgrading an application across a network is usually a simpler process • still benefits greatly from automation

Setting up Applications so users can use them appropriately • Major occupier of network administrators time • The only more time-consuming tasks are installations and managing logons • Need to ensure: • that the required applications ARE available • that users have an appropriate desktop to provide access to them • that users have sufficient rights to use applications in the way they need to use them to do their job, etc.

Ways to make Applications available for Users • Available: • as fat client: • user accesses application from local hard disk • as thin client: • user downloads a copy of the application from the server • via Virtualisation (a server-based virtual machine) • The former is: • quicker and more flexible for the user • a potential pain for the system manager!

Assuming Fat Client Installation… (still the norm) • Essential to make sure the application works as expected FOR THE GROUP(S) OF USERS WHO WILL BE ACCESSING IT! • May need alterations to: • application configuration • user permissions • Also essential to repeat this cycle for each application installed

Rolling out a completed client setup across the network • Could repeat installation processes for each application • create and use unattend scripts to allow installation to proceed automatically • copy each application individually to each client machine • Or could use “disk imaging”

Disk “Imaging” or “Cloning” • The principle is a simple one: • keep a copy of the sector-by-sector contents of the client hard disk on the server • Specialist software is required to achieve this • separate image created for each type of client computer on the network • different hardware requires different drivers • each image needs to be stored on the server

Disk “imaging” – continued • Only computers with identical hardware and applications will have identical disk images • even small hardware changes require different drivers, etc. • A unique image must be created for each batch of computers used • each image will require a large amount of space on the server(s) • Good reason to buy client computers in bulk!

Achieving the disk (or partition) “image” • Software needs to: • scan and copy a hard disk sector • write that sector to a new location • Repeat until all sectors copied • very many sectors involved… • time consuming process • Same principle used in defragmenting files • but latter copied to the SAME partition

Using the Disk Image • Copying the data back from server to client needs careful management: • The client machine needs to have access to an operating system in order to boot up • assuming the BIOS is PXE (Pre-boot eXecution Environment) compliant • Once the client is “active”, it can support copying the image across the network • The client machine, with a full installation of operating system and applications, should reboot, and in theory would be “ready to roll”

Example of a “clean installation” tool (Norton Ghost) • Popular for imaging over many years • Sector-by-sector copying only • this would create identical clients with same IDs • feature allows a unique SID to be added for each Windows client • but not for applications… (problem!) • Image file saved as .ghs (if >2 Gb “spanned”) file

Remote Installation Tools for Managing Installations • A useful tool needs to (unattended installations): • generate unattend scripts for operating system and application setups • manage all aspects of each unattended installation including the allocation of unique IDs • For imaged installations… • create an image (or clone) of a client (or server) hard disks & allow it to be accessible via server • manage the restoration of data by copying the image from a server to a corrupted, but undamaged, hard disk, and resolve ID conflicts

UNATTEND tools with Windows-series networks • WINNT (or WINNT32): Setup program itself • Used with switches e.g. • /s path to allow installation from a remote source • /u path for an unattend script • Unattend.txt • script providing answers to setup questions • Setup Manager • tool that automatically generates unattend.txt files

Windows Application Installer Tool • MSIEXEC.EXE • uses windows installer (.msi) files which provide installation information as a script • executes commands to: • copy files to target machine • make changes to registry • create desktop shortcuts

Windows IMAGING (SYSPREP) • Sysprep • tool specifically for organizations that use disk cloning for mass deployments • will clone a particular machine once an image of an identical machine has been created • further (third party) software is needed to create the image from another client • takes that sector-by-sector copy of the disk

SYSPREP, continued • 1. Strips the SID from the PC being imaged • 2. installs a miniature version of Windows Setup • 3. imaging software clones the "reference machine” • 4. new PC pxe-booted using the new image: • mini-setup runs: • specifies network info, languages and locales, display settings… • question responses can be scripted by using a answer file, sysprep.inf • makes the imaging process totally “hands free”

SYSPREP (continued) • Target PCs must all use the same HAL, NTOSKRNL.EXE, and boot device • Several sysprep support files required: • sysprep.exe, setupcl.exe, others • must be contained in the C:\SYSPREP folder of the image • can be copied from the Deploy folder on the Windows 2000 installation CD

SYSPREP (continued) • Setupmgr.exe used to automate the “mini-setup” process • Answer file must be named sysprep.inf • BOTH saved in the C:\SYSPREP folder • C:\SYSPREP folder removed as part of the installation process

Windows RIS (Remote Installation Service) • Manages the complete process cleanly installing an operating system and applications to a client • not “sector-by-sector” cloning • can cope with different types of client using different UNATTEND files • uses PXE to reboot the client and connect it to the network after disk image created

More about RIS • Three requirements at the server end • not necessarily all on the same machine • should all be on the same subnet) • These are • active RIS on a server (with active directory) to manage the process • active DHCP to deliver the IP address for the client that is to be remote booted • installation files (on a partition separate from RIS) to download and install an operating system on the new client

Sequence of RIS processes • DHCP server supplies IP address to client • RIS server provides boot file & PXE-boot environment for client • Client prompts for F12 to “network boot”

Advanced RIS • RIS equivalent for cloning Windows servers • No real excuse for not having a backup… • if an administrator is capable enough to manage users and clients, server cloning is no more challenging…

COMP3122 Network Management