Using Munki to revert or downgrade software


It might come as little surprise to find out that I use Munki in my organization to manage software installations on macOS.

Munki is really good at keeping software up-to-date. Every time it runs, it compares the versions it has on the server against the versions installed on the local machine and updates any software at a lower version than it has on the server.

Its default behavior when an item on the local machine has a higher version than that on the server is to leave it alone. This is great when you have users that for whatever reason need to test newer versions (or perhaps they are actually developing the newer version of the software).

I also use AutoPkg to automate finding new software updates and to import them into my Munki repo. For us, AutoPkg checks on approximately 50 items each day, importing anything new into my Munki repo into a testing catalog.

On Tuesday of this week, Mozilla released Firefox 59. AutoPkg found the new release and imported it into Munki as expected. On Wednesday, I noticed that AutoPkg had imported Firefox 60! I looked at the installed application, and its version was actually 60.0b3. Someone at Mozilla had goofed and pointed the “latest firefox release” link at the 60 beta. Later in the day this goof was remedied and the link once again returned Firefox 59.

But my AutoPkg run had occurred while the Mozilla site was offering 60.0b3, and so it was downloaded and added to my Munki’s repo’s testing catalog. 25 Macs in my organization (including my own laptop) now had Firefox 60.0b3 installed.

(Side note: because of the way Munki does version comparisons, when the final release of Firefox 60 comes out, if it is versioned as “60.0”,  Munki would not “upgrade” from 60.0b3 to 60.0 – “60.0b3” compares as higher than “60.0”.)

I wanted to configure Munki to downgrade any install of Firefox 60.0b3 to Firefox 59. Since by default Munki leaves higher versions alone, this is not exactly obvious how to do.

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Using Munki to revert or downgrade software 2018 Conference Links

Here are some links from my presentation at Mac Admins and Developers UK 2018, “Imaging is Dead: Now What?”

Der Flounder, “Imaging will be dead soonish”:




Apple, “Upgrade macOS on a Mac at your institution”:

Apple, “APFS and Imaging”:

Restoring an iMac Pro with Configurator:


Erik Gomez, Custom DEP series:

Victor Vranchan, Munkiing around with DEP:

Post-credits scene ( 2018 Conference Links

Early notes on deploying images to iMac Pro


Here are some early notes on making and restoring a High Sierra deployment image to an iMac Pro.

“Wait, I thought imaging was dead! Especially imaging the iMac Pro with Secure Boot!” you may be thinking. My reply: “We’ll see, won’t we?” It’s early days here: we’re experimenting. Our experiments might lead to dead ends, or they might lead to useful results.

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Early notes on deploying images to iMac Pro


A little while ago, I made a new Mac deployment tool available:

Bootstrappr is really nothing more than a Bash script that installs any packages it finds in an adjacent packages directory. There’s no GUI, no bells and whistles.

What is it for? Why would you use it?

You’d use it for installation-based deployment workflows on iMac Pro (and potentially any Mac).

Continue reading “Bootstrappr”


MacSysAdmin 2016 Links

Here are links to various tools, documentation and blog posts I mention in my talk on Thursday at MacSysAdmin 2016:

Apple documentation on running code at login:
Graham Gilbert’s crankd post:
Google macops’

MacSysAdmin 2016 Links

Stupid Tricks with createOSXinstallPkg and VMware Fusion

Like many people tasked with managing OS X/macOS machines, I use VMware Fusion to do a lot of testing. Fusion enables me to test in various versions of OS X, and to easily make changes and revert to a prior state. It’s a great tool.

For some of the testing I do, it’s important to be able to quickly and easily build a VM that is configured just like the “real” machines I manage. There are a few way to do that. Since we build our machines by booting into a NetBoot image and using Graham Gilbert’s excellent Imagr ( to restore an image, it’s great that we can also boot Fusion VMs from a NetBoot image.

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Stupid Tricks with createOSXinstallPkg and VMware Fusion