Resolving a freezing problem on lab Macs

This post has been brewing for a while, and a MacEnterprise thread from today finally got me to write about this problem, and how we resolved it.

Our university has many computer labs – some in public, open spaces, and some in classrooms. Although we don’t use roaming profiles (a technology that Apple finally removed in macOS 10.12), we do bind to Active Directory and create mobile accounts upon logging in with a valid AD account.  To prevent the buildup of cruft, we remove student and faculty accounts periodically. In the public labs, we do it overnight, using a script based off of this one from Marnin Goldberg:

The most important parts of that script are:

# Delete the account
/usr/bin/dscl . -delete $a

This deletes the cached Active Directory account from the system.

# Delete the home directory
/bin/rm -rf $a

This deletes the home folder, freeing up space for more accounts.

We noticed something strange, though. After a couple of weeks of usage, the iMacs in our public labs would freeze at random points: at boot, at login, when using applications, when logging out, even when shutting down. Here’s a list of things we noted while trying to resolve the issue:

  • We use Munki to deploy software, so one by one, we removed potential culprits from the manifests.  Eventually, we whittled down the manifest items to three things we could not remove from this particular lab: Microsoft Office, the Xerox printer driver, and Active Directory binding.
  • We investigated if this was an issue with our network, power, or Active Directory setup.  For a few weeks, all iMacs were plugged into UPSs.
  • We replaced all of the iMacs with brand new models – some with SSDs, and some not.
  • As this issue persisted over ~3 years or so, we tested against multiple macOS versions – including 10.9, 10.10, and 10.11 (and the minor versions in between).
  • We enabled OD debug logging, but couldn’t make much sense of the logs.  They were very, very verbose.
  • Ultimately, the best fix was to reimage the Mac.  This would hold off the freezing for at least another week or two.
  • The freezing seemed linked to computer usage.  If an entire lab was reimaged at the same time, the first Macs to freeze were located near the printers. During the summer, when usage was decreased, we rarely had reports of freezing issues in the public labs.

We were in the process of reaching out to our Apple Systems Engineer, when we found a long-running thread on Jamf Nation, detailing the exact problems we were facing.  It was a relief to see others were trying similar tactics, too.  Then, towards the bottom of the thread, Frank Kong noted that with every use login, some files were being left behind – and the script we were using did not clear those out.  In System Preferences > Sharing > File Sharing, you could see a long list of shares, all named things similar to “Mike Solin’s Public Folder”.  Bingo, there’s our culprit.

Alan Petty, in the same thread, added this code to his profile deletion script:

/usr/bin/find /private/var/db/dslocal/nodes/Default/sharepoints -name "*" -type f -delete
/usr/bin/find /private/var/db/dslocal/nodes/Default/groups -name "*" -type f -delete

We found this code can be run while a user is logged in, so we don’t need to exclude the current user from this part of the script. It will, however, delete all file shares present on the computer (whether they are for public folders or not). This isn’t an issue in our labs, but it’s still worth mentioning.

We’ve had this fix in production for just over a month, and I can safely say the freezing problems haven’t returned.

Long-term, it might be best to look into deleting profiles using a configuration profile – Marnin posted his here.  For now, we’re sticking with the script, as it gives us more control over where and when it runs.

Allow specific users with no password to use sudo

As a sequel to the first post I made to this blog, I’ve found myself tackling this same thing with every macOS release.  Today, however, I discovered a line in /private/etc/sudoers that I hadn’t noticed before:

## Read drop-in files from /private/etc/sudoers.d
## (the '#' here does not indicate a comment)
#includedir /private/etc/sudoers.d

After some research, I discovered that you can drop a file in /private/etc/sudoers.d (a directory), and, as long as the syntax is correct, it will merge those with the main sudoers file.  In the event of a conflict, the last rule that applies takes effect – and, the main sudoers file is read first, so you can essentially override behavior by dropping a file into the sudoers.d directory.  Awesome!

I’ve posted the working code to my GitHub repository.  In the event that you want to make a change, be sure to check the file before packaging it up – or you risk breaking sudo:

/usr/sbin/visudo -csf /path/to/your/file

Adobe Creative Cloud 2014 and Munki

A year ago, we were first getting started with Munki – and deploying Adobe’s Creative Cloud applications was an important goal in our effort to move towards modular deployments. Using Adobe’s Creative Cloud packager, I made individual packages. For some people, we deployed individual apps, but for others, I created manifests that resembled CS6-style “suites.” It worked, and I moved onto other tasks.

We have been deploying the same Adobe CC packages from June 2014 until now. There have been requests for newer versions of these applications, but building newer packages was a significant amount of work – especially because Adobe’s installer packages are randomly broken in a number of different ways.

Recently, Nick McSpadden documented a significantly better method of deploying these apps on the Munki wiki, along with their updates (imported with Tim Sutton’s aamporter). He tested the uninstallers, too, and wrote his own when they didn’t work properly. He also wrote an excellent blog post to further assist Munki administrators in adding the proper metadata for all of the Adobe applications.

Here’s my contribution.

System Requirements

When importing these packages into Munki, I noticed most, if not all, had incorrect OS requirements set in the pkginfo files.  In the interest of simplifying things, I set all of our Adobe packages to require OS X 10.9.5.  When Creative Cloud 2015 is released, it seems that will be the requirement anyway.

PDF Browser Plugin

We’ve had some difficulty in the past with Adobe’s PDF browser plugin. Even though we have an enterprise site license for all of the CC applications, we found with Acrobat 11 that if Acrobat hadn’t ever been launched, and the user viewed a PDF file in their browser, they’d receive an error message about needing to agree to the EULA. Launching Acrobat never displayed a EULA, but it got rid of the browser plugin’s message. This is unacceptable, especially in our computer labs. Originally, our solution was to move the browser plugins to another folder – that way, the user could move them back if they wanted.  In practice, though, we found it easier to delete the plugins entirely.

We’re pushing a package called “removeadobepdfplugin” with the following postinstall script:

It’s set as an update_for the Acrobat package, and also has this installcheck_script:

Application Descriptions

At the end of Nick’s blog post, he mentions Pepijn Bruienne’s suggestion to grab the app descriptions from MacUpdate. Since MacUpdate’s descriptions were incomplete and some needed editing, here are all of the descriptions we’re using:

Acrobat Pro DC

Adobe Acrobat Pro DC with Adobe Document Cloud services is here. Completely reimagined PDF tools let you create, edit, sign, and track PDFs from anywhere. It will change the way you work with design layouts, press-ready files, and all your important documents forever.

After Effects CC 2014

The new, more connected After Effects CC 2014 can make the impossible possible. Get powerful new features like a Live 3D Pipeline that brings CINEMA 4D scenes in as layers – without intermediate rendering. Share work directly from within the application and get access to new features the moment they’re released. Your entire creative world, together in one place.

Audition CC 2014

Adobe Audition CC 2014 empowers you to create and deliver beautiful audio using more connected tools and dozens of new features, including Sound Remover, which can eliminate unwanted sounds from an entire file just by analyzing a small selection. Adobe Audition CC gives you access to new features as soon as they’re released and is integrated with other Adobe video tools for smooth start-to-finish audio and video production. Your entire creative world, together in one place. Only in Creative Cloud.

Bridge CC

Adobe Bridge CC provides you with centralized access to all the media assets you need for your creative projects. Batch edit with ease, add watermarks, and even set centralized color preference — Bridge simplifies your workflow and keeps you organized.

Dreamweaver CC 2014

Adobe Dreamweaver CC 2014 allows you to design, develop, and publish for web and mobile platforms without getting buried in code. Dreamweaver provides an intuitive visual interface for website creation and editing, and offers up-to-date compatibility with web standards as well as first-class support for HTML5/CSS3 and jQuery.

Edge Animate CC 2014

Edge Animate gives web designers the tools they need to add motion to web graphics and create interactive content on their sites, while assuring that their designs display consistently across mobile devices, tablets, and modern browsers.

Edge Code CC

Adobe Edge Code CC is a lightweight code editor for web developers and designers working with HTML, CSS, and JavaScript. Edge is built to work with browsers, speeding up development time by displaying changes to the code directly on the screen.

Edge Reflow CC

Edge Reflow CC enables designers to build beautiful responsive web designs. Create on a native web surface with CSS design and layout features in a familiar and intuitive way. Preview and share your designs on-device through the integrated Edge Inspect plugin. Communicate your website’s responsive behavior and intent, ensuring your design vision isn’t compromised.

ExtendScript Toolkit CC

Access a rich JavaScript development and execution environment to use directly with scriptable Adobe desktop applications. The ExtendScript Toolkit works with many Creative Cloud applications.

Extension Manager CC

The Adobe Extension Manager provides an easy and convenient way to install and delete extensions in many Adobe applications, and to find information about extensions you’ve installed. It also provides a convenient way to navigate to the Adobe Exchange site, where you can find more extensions, get information about extensions, and rate extensions that you’ve used.

Fireworks CS6

Adobe Fireworks CS6 software helps you create beautiful designs for websites and mobile apps in a snap, without coding. Deliver vector and bitmap images, mockups, 3D graphics, and interactive content for popular tablets and smartphones.

Flash Builder Premium

Adobe Flash Builder Premium software is an Eclipse based development tool for rapidly building standout mobile, web, and desktop applications using ActionScript and the open source Flex framework. Use professional testing tools to build higher performing applications.

Flash Professional CC 2014

Flash CC 2014 lets you share work directly from within the application and get access to new features the moment they’re released. Your entire creative world, together in one place. Work faster than ever before with a 64-bit architecture, a new streamlined user interface, and more connected tools. Create HTML content and export high-definition video and audio.

Gaming SDK

Essential set of tools to rapidly build, optimize, and deliver your games to different platforms and devices. These are used by more than 3 million developers across the world.

Illustrator CC 2014

Adobe Illustrator CC 2014 is the industry standard vector-drawing environment for designing across media. Express your creative vision with shapes, color, effects, and typography. Work with speed and stability on large, complex files, and move designs efficiently among Adobe’s creative applications.

InCopy CC 2014

Adobe InCopy CC 2014, ideal for large team projects involving both written copy and design work, provides copywriters and editors with a powerful tool to style text, collaborate through track changes, and make simple layout modifications that integrate effortlessly with InDesign.

InDesign CC 2014

Adobe InDesign CC 2014 is part of Creative Cloud. That means you have access to all the latest updates and future releases the moment they’re available. Sharpen your skills and master new tools with a rich and growing library of training videos. And Creative Cloud is integrated with Behance, so you can share your projects and get immediate feedback from creatives around the world.

Lightroom CC 2015

Adobe Lightroom software helps you bring out the best in your photographs, whether you’re perfecting one image, searching for ten, processing hundreds, or organizing thousands.

Create incredible images that move your audience. Experiment fearlessly with state-of-the-art nondestructive editing tools. Easily manage all your images. And showcase your work in elegant print layouts, slide shows, and Web galleries, as well as on popular photo-sharing sites. All from within one fast, intuitive application.

Media Encoder CC 2014

Adobe Media Encoder CC software automates the process of creating multiple encoded versions of source files, Adobe Premiere Pro sequences, and Adobe After Effects compositions. An intuitive interface, background encoding, and convenient presets help you quickly output for virtually any screen. Adobe Media Encoder is included in Adobe Premiere Pro, After Effects, and Adobe Prelude software.

Muse CC 2014

Adobe Muse enables designers to create websites as easily as creating a layout for print. Design and publish original HTML pages using the latest Web standards, and without writing code. Now in beta, Muse makes it a snap to produce unique, professional-looking websites.

Photoshop CC 2014

Adobe Photoshop CC, the industry standard for digital image processing and editing, delivers a comprehensive package of professional retouching tools, and is packed with powerful editing features designed to inspire.

Prelude CC 2014

Adobe Prelude CC software streamlines your production tasks. Ingest nearly any file-based format and begin logging immediately, creating searchable markers and other temporal metadata that flow through post-production, so you can work faster and stay organized. Adobe Prelude is included in Production Premium, Master Collection, and Creative Cloud.

Premiere Pro CC 2014

Adobe Premiere Pro CC 2014 lets you edit video faster than ever before. Dozens of brand-new features include a redesigned timeline, improved media management, and streamlined color grading. And it’s just the beginning: You’ll get access to new features the moment they’re released. Your entire creative world, together in one place. Only in Creative Cloud.

Scout CC

Adobe Scout is a lightweight but comprehensive SWF profiling tool designed for Flash game developers. Any SWF file, regardless of whether it runs on mobile devices or in browsers, can be quickly profiled with no change to the code, and Adobe Scout quickly and efficiently detects problems that could affect performance.

SpeedGrade CC 2014

Adobe SpeedGrade CC 2014 lets you deliver balanced color and distinctive, vibrant looks for any type of video production. Grade faster with more connected tools, over a dozen powerful new features, and a redesigned interface that’s both intuitive and familiar for Adobe Premiere Pro users. SpeedGrade CC gives you access to ongoing updates as soon as they’re released, and integrates with other Adobe video tools for smooth start-to-finish video production. Your entire creative world, together in one place.

Adobe Utilities

When reading about Extension Manager, Media Encoder, and ExtendScript Toolkit, I found that they’re typically bundled with particular apps. Great! I can use Munki’s ‘requires’ key, rather than including these utilities in manifests.

Per Adobe’s article on Extension Manager, I’ve set these apps to require it:

Flash Professional
Premiere Pro

Per the MacUpdate description for Media Encoder, I’ve set these apps to require it:

After Effects
Premiere Pro

Per Adobe’s page on ExtendScript Toolkit, I’ve set these apps to require it:

After Effects

Since Extension Manager is related to ExtendScript Toolkit, I’ve also added these apps to the previous list:

Flash Professional
Premiere Pro

Now, when any of these apps are installed, they’ll automatically have the appropriate utilities installed along with them.

Edge Code

After packaging it up, I launched Edge Code to see a message that it’s been replaced by Adobe Brackets as of November 2014. Thanks to Jason Stanford, there’s already an AutoPkg recipe for Brackets – that’s one fewer Adobe package you’ll need to create.

Setting preferences on OS X

There are a number of ways to set preferences on OS X. To name a few:

  1. Local MCX
  2. Modifying the User Template
  3. Configuration Profiles (.mobileconfig files)

However, each has a drawback:

  1. Local MCX is rumored to be deprecated in favor of Configuration Profiles.
  2. The User Template exists in /System, which is generally understood to be owned by Apple. OS updates can (and will) replace files in the User Template folder, potentially breaking your changes or causing login issues.
  3. Although useful, Configuration Profiles can be extraordinarily difficult to work with.

Enter: scriptRunner, by Nate Walck. We’ve been deploying this for a couple of months, and it’s helped significantly. Just script what you want to happen at login, decide if you want it to happen once or at every login, then install your script in a specific location. Combined with dockutil, we’ve managed to transition most of our Local MCX settings to Bash scripts (which are pushed out via Munki).

Some settings were difficult to reimplement, though: for example, we wanted to disable Wi-Fi on our lab iMacs – they’re already connected via Ethernet, so there’s no reason for Wi-Fi to be enabled. With Local MCX, we had the ability to disable specific network interfaces, but that’s not possible with Configuration Profiles. What do we do?

Joe Chilcote’s outset proved to be exactly what we needed. Besides adding logging functionality, outset improves upon scriptRunner in that it can:

  1. Install packages at first boot
  2. Run scripts at first boot
  3. Run scripts at every boot
  4. Run scripts at first login
  5. Run scripts at every login

Therefore, our solution was to run a script at every boot that disabled Wi-Fi.

At the moment, the Macs on campus are running a range of 10.6.x to 10.9.x. Since outset has only been tested on 10.9.x, we’re pushing scriptRunner to Macs running 10.6.x to 10.8.x, and outset to Macs running 10.9.x. scriptRunner’s paths have been changed to match outset’s, so we can push the same scripts to both.

Tested with: 10.6, 10.7, 10.8, 10.9, 10.10

Customizing the login window in Mavericks

Before 10.9 Mavericks, customizing the login window was a sometimes complicated process. Apple has changed the resources for the login window several times over the years.

If possible, it’s generally a good idea to stay away from altering system files. However, our Windows PCs are branded, so we’d like to do the same for our Macs. With 10.9, we’ve settled upon replacing the Apple logo with our own.

We started off using this tutorial from OS X Daily – however, we found that the results weren’t consistent when replacing the Apple logo images with full-sized backgrounds as the tutorial recommends. With so many resolutions to support, we found that our custom background didn’t always cover the default gray Apple background.

Instead, after much testing, we came up with this:

  1. In the Finder, type Command-Shift-G and open /System/Library/PrivateFrameworks/LoginUIKit.framework/Versions/A/Frameworks/LoginUICore.framework/Resources/
  2. Make backups of these files: “apple_s1.png”, “apple_s1@2x.png”, “apple.png”, and “apple@2x.png”.
  3. Open each file in an image editor (I like Acorn), and double the size of each image.  Delete the Apple logo and replace it with a transparent version of your own.
  4. Copy your modified versions of these files back to their original folder, replacing Apple’s versions.

Log out, and you should see your logo just above the username and password fields. I have not tested against a login window using names and pictures, but it should be fine.

If Apple modifies these files in a future OS X update, you might need to replace them again. I’d recommend packaging them up for easy reinstallation.

Tested with: 10.9

Enabling and configuring NFS

This weekend, I had a need to get NFS working on my Mac. My reasoning? I have a WDTV Live, and found that streaming video through NFS adds less overhead than using (the excellent and free) PS3 Media ServerWestern Digital’s instructions are GUI-heavy and somewhat incomplete, though, so I decided to write my own.

To configure NFS, you’ll need to create a file in /etc/exports:

sudo nano /etc/exports

If the file doesn’t already exist, it should be empty. This file contains your list of shares. Here’s an example of a share from my machine:

/Users/mike/Downloads -ro -network -mask

Breaking it down – first, you’ve got the path to the folder you want to share. Next, it’s set so that anyone connecting has read-only access. And finally, the two last sections detail the IP range that’s allowed to access shares on your NFS server. There are many more options you can add – see this for a full listing:

man exports

Add one share per line. Once you’re happy with your exports file, all you need to do is enable NFS:

sudo nfsd enable

This will start the NFS service and keep it running, even after a reboot. You can also start and stop it on an as-needed basis:

sudo nfsd start
sudo nfsd stop

If you make changes to your exports file, you might need to restart the NFS daemon for your changes to take effect:

sudo nfsd restart

If you’d like to verify that your exports file is properly formatted, this will be useful:

nfsd checkexports

And finally, if NFS is running, you can get a listing of all of your shares (‘mounts’ in NFS terminology) via this:

showmount -e

Hope this is useful to someone! If you’d prefer a GUI anyway, NFS Manager looks to be very well done.

Tested with: 10.7, 10.8, 10.9