TweetFollow Us on Twitter

MacEnterprise: "Image"ine That!

Volume Number: 24 (2008)
Issue Number: 03
Column Tag: MacEnterprise

MacEnterprise: "Image"ine That!

A fresh look at creating deployment images

By Philip Rinehart, Yale University

Images?

In the System Imaging and Deployment Power Tools session at Macworld this year, there was a large amount of time spent discussing system imaging. How does it work? What are best practices? Are there best practices? How do you deal with new hardware, and more were asked. I thought it would be useful this month to reexamine the practice of image creation. Let's start by looking at what we mean by an image.

The "Image"

In traditional Macintosh system administration, an image is a base operating system plus some amount of software that is applied to one or more machines. In general, the nirvana has been to create a single image that can be applied to many different models of Mac machines. Is this goal achievable, or is it like Buddhism, in which the journey is more important?

Rule 1: currency

The first rule of system imaging is that an image must be created from the most current model of Macintosh in any deployment. Typically this image is created from the installation media that was shipped with the hardware. For example, if your deployment includes a quad core Intel machine, then create the image from that disc. Is this rule inviolable? No.

How do you update an existing image? Wait until the dot release update. That is, if your image was created on 10.4.10, update your image for new hardware at 10.4.11. There is some debate about using a combo updater or a delta. Generally, I prefer to use the combo updater, as each and every update from the Gold Master is applied. This method can be used to update existing images pretty reliably. There are of course exceptions, but now that a universal operating system is available, Leopard, this method should work in most cases.

Rule 2: User templates

The second rule of thumb in system imaging is how to create a default template. Note that this method applies to local accounts, not network accounts. First, create a template user using system preferences. Next, login as that user, and run each application that it is important to configure. Common configuration items include web browsers, word processing applications, or site-specific applications that need consistent settings. There are a couple of gotchas though.

First, for the template user, don't store anything in the keychain. When the template is copied over any item stored in the keychain will be inaccessible to the new account. It is safe to delete the keychain after finishing custom configuration as well. Secondly, be certain to set the proper downloads folder for each web browser. In Tiger, if the Safari download folder were not set, a copied template would contain an inaccessible path. The last gotcha is for any preferences that are machine specific. This type of preference is usually stored in ~/Library/Preferences/ByHost. Common items here include iTunes preferences, screensaver preferences, and others. A hardware address is embedded in the preference file name. It can be corrected with a loginhook.

Rule 3: Cleanup

Before applying any image, it is important to do some basic cleanup. What should be cleaned up though? There are a few obvious things to remove for initial cleanup. Get rid of any Cache files stored in /Library/Caches, and /System/Library/Caches. Next, remove both swap files and sleep images. These are located in the directory /var/vm, and can be significant in size. One other cache can also be removed, the BootCache.playlist located in /private/var/db.

What about other types of files? Generally, I would recommend moving the Network Interfaces plist in /Library/Preferences/SystemConfiguration. In general, these files are machine specific, and will get recreated by the operating system on first boot. This also removes any possible conflict if an image has a different network interface configuration then its target.

System wide, these files are ignored by Time Machine, and can probably be eliminated from any image.

                      /.Spotlight-V100
                /.Trashes
                /.fseventsd
                /.hotfiles.btree
                /Backups.backupdb
                /Desktop DB
                /Desktop DF
                /Network/Servers
                /Previous Systems
                /Users/Shared/SC Info
                /Users/Guest
                /dev
                /home
                /net
                /private/var/db/Spotlight
                /private/var/db/Spotlight-V100

Note that most of these files are fairly logical to be excluded. The operating system will recreate any of these files at first boot.

Clean up of the User Template can also be a little more complete as well. Here are the files that can be excluded from the User Template. Most are related to browsers and rss feeds.

                    Library/Application Support/MobileSync
                Library/Application Support/SyncServices
                Library/Caches
                Library/Logs
                Library/Mail/Envelope Index
                Library/Mail/AvailableFeeds
                Library/Mirrors
                Library/PubSub/Database
                Library/PubSub/Downloads
                Library/PubSub/Feeds
                Library/Safari/Icons.db
                Library/Safari/HistoryIndex.sk

The last thing to eliminate is any Log files, both in /Library/Logs and /private/var/log. No need to have any of these items on an image! Note that the cleanup process is best scripted, as no one really wants to remember all of these steps!

Apple software restore

Now that you have created your "perfect" image, it is time to get it ready for deployment. Are there best practices here? I think so. First, it is best to boot from an alternate volume. This volume can be a separate partition, or an external drive. Once booted the steps are pretty straightforward.

1. Open Disk Utility

2. Select the drive or partition that is the model for imaging

3. Select "Image from Folder" and select the hard drive and wait. A long time.

4. Select "Scan Image for Restore" and scan the newly created dmg file.

That's it! You then have an image that is ready for deployment via whatever method you have in place to put an image on a machine via multicast ASR, NetRestore, or any other method you have of getting the image on the machine. One important note though, it is generally best to have at least twice the amount of space needed to create an image on your external drive. If your drive has any less than that, the imaging operation may fail.

The future

The method I have just described is the "Classic" way of creating methods and is fairly tried and true. However, it isn't really very scalable, or flexible as the image is a point in time snapshot. The way of the future can be seen in two areas, the new System Imaging Utility in Leopard and InstaDMG from afp548.com. Both take the idea of monolithic image creation, and move it to a more modular approach. Ultimately this approach is far more flexible, allowing updating any image at a moments notice. It also makes it easier to be extremely flexible and adaptable, which is a good thing in today's fast moving environments. It was good to see all at Macworld this year, until next month see you on the lists!


Philip Rinehart is co-chair of the steering committee leading the Mac OS X Enterprise Project (macenterprise.org) and is the Lead Mac Analyst at Yale University. He has been using Macintosh Computers since the days of the Macintosh SE, and Mac OS X since its Developer Preview Release. Before coming to Yale, he worked as a Unix system administrator for a dot-com company. He can be reached at: philip.rinehart@yale.edu. The MacEnterprise project is a community of IT professionals sharing information and solutions to support Macs in an enterprise. We collaborate on the deployment, management, and integration of Mac OS X client and server computers into multi-platform computing environments.

 
AAPL
$98.15
Apple Inc.
-0.23
MSFT
$43.58
Microsoft Corpora
-0.31
GOOG
$587.42
Google Inc.
+1.81

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mellel 3.3.6 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
LibreOffice 4.3.0.4 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Freeway Pro 7.0 - Drag-and-drop Web desi...
Freeway Pro lets you build websites with speed and precision... without writing a line of code! With it's user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of... Read more
Drive Genius 3.2.4 - Powerful system uti...
Drive Genius is an OS X utility designed to provide unsurpassed storage management. Featuring an easy-to-use interface, Drive Genius is packed with powerful tools such as a drive optimizer, a... Read more
Vitamin-R 2.15 - Personal productivity t...
Vitamin-R creates the optimal conditions for your brain to work at its best by structuring your work into short bursts of distraction-free, highly focused activity alternating with opportunities for... Read more
Toast Titanium 12.0 - The ultimate media...
Toast Titanium goes way beyond the very basic burning in the Mac OS and iLife software, and sets the standard for burning CDs, DVDs, and now Blu-ray discs on the Mac. Create superior sounding audio... Read more
OS X Yosemite Wallpaper 1.0 - Desktop im...
OS X Yosemite Wallpaper is the gorgeous new background image for Apple's upcoming OS X 10.10 Yosemite. This wallpaper is available for all screen resolutions with a source file that measures 5,418... Read more
Acorn 4.4 - Bitmap image editor. (Demo)
Acorn is a new image editor built with one goal in mind - simplicity. Fast, easy, and fluid, Acorn provides the options you'll need without any overhead. Acorn feels right, and won't drain your bank... Read more
Bartender 1.2.20 - Organize your menu ba...
Bartender lets you organize your menu bar apps. Features: Lets you tidy your menu bar apps how you want. See your menu bar apps when you want. Hide the apps you need to run, but do not need to... Read more
TotalFinder 1.6.2 - Adds tabs, hotkeys,...
TotalFinder is a universally acclaimed navigational companion for your Mac. Enhance your Mac's Finder with features so smart and convenient, you won't believe you ever lived without them. Tab-based... Read more

Latest Forum Discussions

See All

Star Admiral Review
Star Admiral Review By Rob Thomas on July 30th, 2014 Our Rating: :: ADMIRABLE ADMIRALSUniversal App - Designed for iPhone and iPad While this new digital CCG may feel a bit familiar, Star Admiral offers a sci-fi twist and galaxy’s... | Read more »
Zap! Pow! Become a Badass Wizard in Phan...
Zap! Pow! | Read more »
Urban Trial Freestyle Review
Urban Trial Freestyle Review By Blake Grundman on July 30th, 2014 Our Rating: :: RIDIN' DIRTYUniversal App - Designed for iPhone and iPad A rough ride that has trouble keeping its wheels on the track.   | Read more »
Take Note! Noteshelf Has Recieved a Big...
Take Note! Noteshelf Has Recieved a Big Update. Posted by Jessica Fisher on July 30th, 2014 [ permalink ] iPad Only App - Designed for the iPad | Read more »
Cubama Review
Cubama Review By Nadia Oxford on July 30th, 2014 Our Rating: :: TETRIIIIIS IIIIIN SPAAAAACE!Universal App - Designed for iPhone and iPad With its addictive challenge and interesting premise, Cubama is frantic screen-tapping fun.   | Read more »
Become a Guardians of Galactic Peace Wit...
Become a Guardians of Galactic Peace With the New Spacefaring Sim, Kairobotica. Posted by Jessica Fisher on July 30th, 2014 [ permalink ] | Read more »
Soul Guardians: Age of Midgard Review
Soul Guardians: Age of Midgard Review By George Fagundes on July 30th, 2014 Our Rating: :: SO MUCH GRIND IT CRUNCHESUniversal App - Designed for iPhone and iPad Swords and trading cards are fun, right? So is Soul Guardians: Age of... | Read more »
NFL Fantasy Football App Redesigned Ahea...
NFL Fantasy Football App Redesigned Ahead of Upcoming 2014 Season Posted by Ellis Spice on July 30th, 2014 [ permalink ] | Read more »
Matter Review
Matter Review By Jennifer Allen on July 30th, 2014 Our Rating: :: ORIGINAL PHOTO MANIPULATIONUniversal App - Designed for iPhone and iPad Matter lets you add geometric 3d shapes to your images and manipulate things so each image... | Read more »
Note Review
Note Review By Jennifer Allen on July 29th, 2014 Our Rating: :: TOO SIMPLEiPhone App - Designed for the iPhone, compatible with the iPad Note is a note taking app that’s a little too short on features to be worth its asking price... | Read more »

Price Scanner via MacPrices.net

More iPad Upgrade Musings – The ‘Book Mystiqu...
Much discussed recently, what with Apple reporting iPad sales shrinkage over two consecutive quarters, is that it had apparently been widely assumed that tablet users would follow a two-year hardware... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $999.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $100 off MSRP. Price is... Read more
Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
WaterField Unveils 15″ Outback Solo & 13″...
Hard on the heels of Apple’s refreshed MacBook Pro Retina laptops announcement, WaterField Designs has unveiled a 15-inch version of the waxed-canvas and leather Outback Solo and a 13-inch version of... Read more
New Roxio Toast 12 Delivers Digital Media Pow...
Roxio Toast 12 is a hub for sharing digital media to virtually any platform or device. has introduced two new additions to its Roxio Toast product family – Roxio Toast 12 Titanium and Roxio Toast 12... Read more
The lowest prices on leftover Retina MacBook...
Best Buy has dropped prices on leftover 13″ and 15″ Retina MacBook Pros by up to $300 off original MSRP on their online store for a limited time. Choose free local store pickup (if available) or free... Read more
Apple Updates MacBook Pro with Retina Display...
Apple today updated its MacBook Pro with Retina display with faster processors and double the amount of memory in both entry-level configurations. MacBook Pro with Retina display features a Retina... Read more
Up to $250 price drop on leftover 15-inch Mac...
B&H Photo has dropped prices on 2013 15″ Retina MacBook Pros by as much as $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.3GHz Retina MacBook Pro: $2349... Read more
Updated MacBook Pro Price Trackers
We’ve updated our MacBook Pro Price Trackers with the latest information on prices, bundles, and availability on the new 2014 models from Apple’s authorized internet/catalog resellers as well as... Read more
Apple updates MacBook Pros with slightly fast...
Apple updated 13″ and 15″ Retina MacBook Pros today with slightly faster Haswell processors. 13″ models now ship with 8GB of RAM standard, while 15″ MacBook Pros ship with 16GB across the board. Most... Read more

Jobs Board

Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr. Product Leader, *Apple* Store Apps - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.