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.

 
AAPL
$111.78
Apple Inc.
-0.87
MSFT
$47.66
Microsoft Corpora
+0.14
GOOG
$516.35
Google Inc.
+5.25

MacTech Search:
Community Search:

Software Updates via MacUpdate

Monolingual 1.6.2 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
NetShade 6.1 - Browse privately using an...
NetShade is an Internet security tool that conceals your IP address on the web. NetShade routes your Web connection through either a public anonymous proxy server, or one of NetShade's own dedicated... Read more
calibre 2.13 - Complete e-library manage...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Mellel 3.3.7 - 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
ScreenFlow 5.0.1 - Create screen recordi...
Save 10% with the exclusive MacUpdate coupon code: AFMacUpdate10 Buy now! ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your... Read more
Simon 4.0 - Monitor changes and crashes...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
BBEdit 11.0.2 - Powerful text and HTML e...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
ExpanDrive 4.2.1 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
Adobe After Effects CC 2014 13.2 - Creat...
After Effects CC 2014 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). After Effects CS6 is still available... Read more
Evernote 6.0.5 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more

Latest Forum Discussions

See All

Make your own Tribez Figures (and More)...
Make your own Tribez Figures (and More) with Toyze Posted by Jessica Fisher on December 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
So Many Holiday iOS Sales Oh My Goodness...
The holiday season is in full-swing, which means a whole lot of iOS apps and games are going on sale. A bunch already have, in fact. Naturally this means we’re putting together a hand-picked list of the best discounts and sales we can find in order... | Read more »
It’s Bird vs. Bird in the New PvP Mode f...
It’s Bird vs. Bird in the New PvP Mode for Angry Birds Epic Posted by Jessica Fisher on December 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Telltale Games and Mojang Announce Minec...
Telltale Games and Mojang Announce Minecraft: Story Mode – A Telltale Games Series Posted by Jessica Fisher on December 19th, 2014 [ permalink ] | Read more »
WarChest and Splash Damage Annouce Their...
WarChest and Splash Damage Annouce Their New Game: Tempo Posted by Jessica Fisher on December 19th, 2014 [ permalink ] WarChest Ltd and Splash Damage Ltd are teaming up again to work | Read more »
BulkyPix Celebrates its 6th Anniversary...
BulkyPix Celebrates its 6th Anniversary with a Bunch of Free Games Posted by Jessica Fisher on December 19th, 2014 [ permalink ] BulkyPix has | Read more »
Indulge in Japanese cuisine in Cooking F...
Indulge in Japanese cuisine in Cooking Fever’s new sushi-themed update Posted by Simon Reed on December 19th, 2014 [ permalink ] Lithuanian developer Nordcurrent has yet again updated its restaurant simulat | Read more »
Badland Daydream Level Pack Arrives to C...
Badland Daydream Level Pack Arrives to Celebrate 20 Million Downloads Posted by Ellis Spice on December 19th, 2014 [ permalink ] | Read more »
Far Cry 4, Assassin’s Creed Unity, Desti...
Far Cry 4, Assassin’s Creed Unity, Destiny, and Beyond – AppSpy Takes a Look at AAA Companion Apps Posted by Rob Rich on December 19th, 2014 [ permalink ] These day | Read more »
A Bunch of Halfbrick Games Are Going Fre...
A Bunch of Halfbrick Games Are Going Free for the Holidays Posted by Ellis Spice on December 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »

Price Scanner via MacPrices.net

The Apple Store offering free next-day shippi...
The Apple Store is now offering free next-day shipping on all in stock items if ordered before 12/23/14 at 10:00am PT. Local store pickup is also available within an hour of ordering for any in stock... Read more
It’s 1992 Again At Sony Pictures, Except For...
Techcrunch’s John Biggs interviewed a Sony Pictures Entertainment (SPE) employee, who quite understandably wished to remain anonymous, regarding post-hack conditions in SPE’s L.A office, explaining “... Read more
Holiday sales this weekend: MacBook Pros for...
 B&H Photo has new MacBook Pros on sale for up to $300 off MSRP as part of their Holiday pricing. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1699... Read more
Holiday sales this weekend: MacBook Airs for...
B&H Photo has 2014 MacBook Airs on sale for up to $120 off MSRP, for a limited time, for the Thanksgiving/Christmas Holiday shopping season. Shipping is free, and B&H charges NY sales tax... Read more
Holiday sales this weekend: iMacs for up to $...
B&H Photo has 21″ and 27″ iMacs on sale for up to $200 off MSRP including free shipping plus NY sales tax only. B&H will also include a free copy of Parallels Desktop software: - 21″ 1.4GHz... Read more
Holiday sales this weekend: Mac minis availab...
B&H Photo has new 2014 Mac minis on sale for up to $80 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 1.4GHz Mac mini: $459 $40 off MSRP - 2.6GHz Mac mini: $629 $70 off MSRP... Read more
Holiday sales this weekend: Mac Pros for up t...
B&H Photo has Mac Pros on sale for up to $500 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2599, $400 off MSRP - 3.5GHz 6-core Mac Pro: $3499, $... Read more
Save up to $400 on MacBooks with Apple Certif...
The Apple Store has Apple Certified Refurbished 2014 MacBook Pros and MacBook Airs available for up to $400 off the cost of new models. An Apple one-year warranty is included with each model, and... Read more
Save up to $300 on Macs, $30 on iPads with Ap...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
iOS and Android OS Targeted by Man-in-the-Mid...
Cloud services security provider Akamai Technologies, Inc. has released, through the company’s Prolexic Security Engineering & Research Team (PLXsert), a new cybersecurity threat advisory. The... Read more

Jobs Board

*Apple* Store Leader Program (US) - Apple, I...
…Summary Learn and grow as you explore the art of leadership at the Apple Store. You'll master our retail business inside and out through training, hands-on experience, Read more
Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.