TweetFollow Us on Twitter

Desktop Systems Engineer and Analyst

Volume Number: 22 (2006)
Issue Number: 3
Column Tag: Interview

In The Trenches

Desktop Systems Engineer and Analyst

by Schoun P. Regan

Interviewing Kevin Denges: Kevin is in charge of the image creation and deployment for Conde Nast. I spoke with him in New York City, at his office.

Schoun: Kevin, tell me about the setup.

Kevin: We have a Windows Active Directory infrastructure for authentication. The Macs are bound to the Active Directory server and the Xserves are used as image servers, primary and secondary K4 servers. K4 is our Adobe InDesign workflow. Each server is setup using 2 Xserve's, one primary and a second mirror for failover. We started all this with Mac OS X 10.3.3, so we've been at it for some time.

Schoun: And for file servers?

Kevin: We are using Extreme z-ip version 4. We started to deploy them in Sept/Oct of this year to our Windows servers, and by doing so, now have single sign on using Kerberos.

Schoun: What about the Macs? How are they deployed? NetBoot?

Kevin: No. The Xserves are just image servers for the most part. We use FireWire drives to deploy our images, but we also store those images on a server. So if a tech ever needs to get a newer image, they boot off of a FireWire drive and install the latest image from our servers.

Schoun: Sounds like NetBoot may solve the booting from FireWire issue.

Kevin: We are looking into that, but for right now, FireWire drives are the most efficient for us.

Schoun: So one image to rule them all?

Kevin: Nope. We have an image that has all the software they need, and one main image. There are older images with 10.3 on them also. It depends on where the computer is placed and with whom as to what image they receive on their Mac.

Schoun: So the image build, it's stock Mac OS X?

Kevin: For the most part yes. We have leveraged the power of launchd to handle some initial binding and computer setup for us, but other than that, it's stock with Adobe's CS2 suite.

Schoun: Take us through the launchd file.

Kevin: Well basically it's very simple, it starts when the machine boots and runs a shell script that we have. Here's what it looks like:


Figure 1.

Kevin: We also have another launchd item that handles the fixing of ByHost files.

Schoun: First tell me about the AD binding launchd item:

Kevin: As you can see, it runs at boot time, waits 2 seconds, then renices to get processor authority, to run ahead of other items. It then calls the shell script ADhook.sh located in a directory I chose. Pretty simple actually.

Schoun: Is the ByHost launchd item the same?

Kevin: For the most part yes, except it calls another script of course.

Schoun: So lets look at the AD script then. We know that the Active Directory plug-in has a command line counterpart, dsconfigad. I assume you use this?

Kevin: It's now a small part of the script, but yes, it is the integral part. The script is divided into four major parts; network connectivity, AD binding, ByHost fixes, and file deletion.

Schoun: Can we walk through some of the major portions of the script?

Kevin: Sure, but keep in mind that some of this came from Mike Bombich's site, so credit goes to him for some of this.

Schoun: I'll let him know.

Kevin: So as we can see, the first part of the script creates a log file for us to write to, then we check for network connectivity.


Figure 2.

Schoun: I see Vicki in here.

Kevin: Yes. The problem we sometimes encountered was that a tech would download an image, and reboot the Mac only to find the Mac was not on the network. Or, in certain cases, the Macs would unbind and we would have to rebind them. Either way, the script now checks for not just network connectivity, but if the Mac is connected to our network. It announces its findings using the voice Vicki on the Mac. This way our techs know whether the machine is binding or not.

Schoun: Part of this script looks familiar.


Figure 3.

Kevin: [laughs] I borrowed-and gave credit to-Mike Bombich as this is based on the script called, "Who stole my Mac script". It was important to us, to make sure our techs knew what the status was, when they imaged a machine. This helps us track binding issues.

Schoun: Let's talk about the AD binding.

Kevin: Sure. Before I run the actual bind, I set all the parameters. This part of the script sets the parameters.


Figure 4.

Schoun: I see the uuidgen command in there! I should explain to our readers that uuidgen is a command that creates a unique ID, unique enough that the man page states, "The uuidgen command generates a Universally Unique Identifier (UUID), a 128-bit value guaranteed to be unique. A UUID is made unique over both space and time by combining a value unique to the computer on which it was generated--usually the Ethernet hardware address--and a value representing the number of 100-nanosecond intervals, since October 15, 1582 at 00:00:00." You gotta love Apple code writers sometimes. "Unique over space AND time" Ha.

Kevin: Well, the issue is that if a Mac binds to an AD domain, the AD domain cannot use that computer name to bind more than twice. So, if a computer's name is already in the AD domain, and our techs re-image it, the bind fails. Using a portion of the uuidgen output insures us a unique ID with which to bind the Mac.

Schoun: I also see that you did not put the password into this script for the actual bind. That you are calling the output of an AppleScript file. Why?

Kevin: Security. This way the script calls the AppleScript file and it returns the password. Just a little more secure this way.

Schoun: So with all the variables set, now the bind?

Kevin: Yes. Again we used the dsconfigad command line tool for that. We of course write to the log file, check for an older edu.mit.Kerberos file and get rid of it, if one exists, and set the search policies.


Figure 5.

Schoun: I see a sleep command in there.

Kevin: It seemed to go smoother when we did this.

Schoun: Then the ByHost issues? Why the problem?

Kevin: As you know, ByHost files are MAC address specific, so we have them set the way we want, then we put all Xs in the place of the address. We then copy these and replace the Xs with the local Mac's MAC address. We do this for the template for any user's that log in via AD, our local administrator account, and a hidden account we have.


Figure 6.

Schoun: And the last part of the script?

Kevin: Checking the bind, having Vicki notify the tech, and then deleting the launchd item, the AppleScript file with the password, and then deleting itself, killing the loginwindow process and having it come back. This way, the AD user can log in and get a newly created home folder, with all the customized tweaks we've added in the user template, such tweaks to the .GlobalPreferences file, the Dock, the menu bar, the screen saver, the background, and so on.


Figure 7.

Schoun: This is in incredibly powerful script. Again I see some of Mike's work in here, but you have done a nice job of pulling it all together.

Kevin: Thanks. Our next step is to take this and make a launchd item that watches the bind and if it fails, it deletes the /Library/Preferences/edu.mit.Kerberos file, the DirectoryServices directory inside of the same location, and pulls them from a hidden location on the local disk and rebinds the machine automatically.

Schoun: I would also suggest, you use the mail command to email an administrator account, when this occurs. In this way, your techs can be a bit more proactive than reactive. They will know when a machine unbinds.

Kevin: Yea. We want to do more with launchd and scripts.

Schoun: Kevin, this is all we have time for, but I know you have more to say about your setup. I think this script is an excellent place to start. It gives the reader a clear- cut way of implementing this type of bind. I'd like to talk to you more about how this interacts with the local NetInfo database and what other tweaks you've done to the system.

Kevin: Be happy to. We are very confident in our process, and have moved to cut down time to under 5 minutes, if possible.

Schoun: I think our readers will be excited to learn about what else you have done.

Ed Note: Kevin has much more to say about his infrastructure but this time I wanted to focus on the script itself.

Vital Stats

Years in IT industry : 6

Information: Kevin is in charge of the image creation and deployment for Conde Nast.

Computers: About 2700 Macs, 42 Xserves, 4 Xserve RAIDs, Windows Active Directory Servers, wireless networks.

Programming Languages:Shell Scripting, AppleScript


Schoun P. Regan is CEO of ITInstruction.com, which specializes in Mac OS X training and consulting. He speaks regularly to CEOs and CFOs on how to control IT department spending, the myths surrounding cross-platform integration, and the lunacy of expected lost revenue stemming from a culture bred to tolerate IT staff and operating system inadequacies as "normal". He seeks to change self-fulfilling IT departments that breed complacency for their jobs and contempt for the end user, neither of which are conducive to business.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Cyberduck 4.7.1 - FTP and SFTP browser....
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
PDFpen 7.2 - Edit and annotate PDFs with...
We're also offering PDFpenPro for 30% off! PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even... Read more
Skype 7.9.746 - Voice-over-internet phon...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
Apple GarageBand 10.1 - Complete recordi...
The new GarageBand is a whole music creation studio right inside your Mac -- complete with keyboard, synths, orchestral and percussion instruments, presets for guitar and voice, an entirely... Read more
Duplicate Annihilator 5.7.7 - Find and d...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator... Read more
OS X Server 4.1.3 - For OS X 10.10 Yosem...
Designed for OS X and iOS devices, OS X Server makes it easy to share files, schedule meetings, synchronize contacts, develop software, host your own website, publish wikis, configure Mac, iPhone,... Read more
Firefox 39.0 - Fast, safe Web browser. (...
Firefox offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals and casual... Read more
pwSafe 4.1 - Secure password management...
pwSafe provides simple and secure password management across devices and computers. pwSafe uses iCloud to keep your password databases backed-up and synced between Macs and iOS devices. It is... Read more
Kodi 15.0.rc1 - Powerful media center to...
Kodi (was XBMC) is an award-winning free and open-source (GPL) software media player and entertainment hub that can be installed on Linux, OS X, Windows, iOS, and Android, featuring a 10-foot user... Read more
Coda 2.5.11 - One-window Web development...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few surprises... Read more

This Week at 148Apps: June 29-July 3, 20...
Into July With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above the... | Read more »
Sonic Runners Guide
Despite its flaws, Sonic Runners' platforming action is actually quite fun. Though it can be a little more complicated than old-school Sonic games. Here's how to make sure you're up to speed when jumping in. [Read more] | Read more »
Rage of Bahamut is Giving Almost All of...
The App Store isn't what it used to be back in 2012, so it's not unexpected to see some games changing their structures with the times. Now we can add Rage of Bahamut to that list with the recent announcement that the game is severely cutting back... | Read more »
Adventures of Pip (Games)
Adventures of Pip 1.0 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: ** ONE WEEK ONLY — 66% OFF! *** “Adventures of Pip is a delightful little platformer full of charm, challenge and impeccable... | Read more »
Divide By Sheep - Tips, Tricks, and Stre...
Who would have thought splitting up sheep could be so involved? Anyone who’s played Divide by Sheep, that’s who! While we’re not about to give you complete solutions to everything (because that’s just cheating), we will happily give you some... | Read more »
NaturalMotion and Zynga Have Started Tea...
An official sequel to 2012's CSR Racing is officially on the way, with Zynga and NaturalMotion releasing a short teaser trailer to get everyone excited. Well, as excited as one can get from a trailer with no gameplay footage, anyway. [Read more] | Read more »
Grab a Friend and Pick up Overkill 3, Be...
Overkill 3 is a pretty enjoyable third-person shooter that was sort of begging for some online multiplayer. Fortunately the begging can stop, because its newest update has added an online co-op mode. [Read more] | Read more »
Scanner Pro's Newest Update Adds Au...
Scanner Pro is one of the most popular document scanning apps on iOS, thanks in no small part to its near-constant updates, I'm sure. Now we're up to update number six, and it adds some pretty handy new features. [Read more] | Read more »
Heroki (Games)
Heroki 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: CLEAR THE SKIES FOR A NEW HERO!The peaceful sky village of Levantia is in danger! The dastardly Dr. N. Forchin and his accomplice,... | Read more »
Wars of the Roses (Games)
Wars of the Roses 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

Apple refurbished Mac minis available startin...
The Apple Store has Apple Certified Refurbished 2014 Mac minis available starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: - 1.4GHz Mac mini: $419 $80 off... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through August 8, 2015. Anyone with a valid .EDU email address can take... Read more
Sky Atlas Star Walk 2 App For iPhone And iPa...
Vito Technology, developer of educational apps for Android and iOS, is for a limited time offering free of charge their Star Walk 2, the next generation of the company’s best-selling stargazing guide... Read more
13-inch 1.6GHz MacBook Air on sale for $849,...
Amazon has the 2015 13″ 1.6GHz/128GB MacBook Air on sale for $849.99 including free shipping. Their price is $150 off MSRP, and it’s the lowest price available for this model. Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Adorama has the 13-inch 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has new 2015 15″ Retina MacBook Pros on sale for up to $225 off MSRP including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1819 $180 off - 15″ 2.5GHz Retina... Read more
RamDisk4Mac App Helps Run Your Mac Faster And...
Ever use a RAM disk? If you’ve come to the Mac in the OS X era, likely not. The Classic Mac OS had a RAM disk function built-in, but that was dropped in the conversion to OS X. What is a RAM disk?... Read more
13-inch 1.6GHz MacBook Air on sale for $849,...
Best Buy has the 2015 13″ 1.6GHz/128GB MacBook Air on sale for $849.99 on their online store this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders... Read more
Apple Refurbished iMacs available for up to $...
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $... Read more

Jobs Board

*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
Senior Payments Security Manager - *Apple*...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments security manager to join the Apple Pay security team. You will Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Sr. Payment Program Manager, *Apple* Pay -...
**Job Summary** Apple Pay is an exciting environment and a…devices in a simple, private and secure way. The Apple Pay Team is looking for an experienced Senior Read more
Project Manager - *Apple* Pay Security - Ap...
**Job Summary** The Apple Pay Security team is seeking a highly organized, results-driven Project Manager to drive the development of Apple Pay Security. If you are Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.