Endpoint Services, Munki, Using Munki to Upgrade macOS
This article provides guidance on using Munki to perform in-place macOS upgrades without disturbing user data.
Looking to instead perform a clean macOS install? Here's how.
Munki Mac Endpoint Management
University of Illinois IT Pros leveraging Technology Services Endpoint Service Munki Mac Endpoint Management
- General Information
- Hardware Support Considerations
- Vital Software Compatibility
- Optional vs. Managed Installs
- Restart Required
Multi-Tenant Munki can be used to perform in-place macOS upgrades (e.g. from macOS 10.14.x to macOS 10.15.x) without disturbing user data. These upgrades use Apple's own 'startosinstall' upgrade mechanism built into macOS installer packages, ensuring that any required firmware updates are applied during the upgrade.
Upgrade packages for macOS 11.0 (Big Sur), macOS 10.15 (Catalina), macOS 10.14 (Mojave), and macOS 10.13 (High Sierra) are available for MTM stakeholder use. The upgrade installer name keys are install_macos_[bigsur/catalina/mojave/high_sierra].
Before planning an OS upgrade, check Apple's system requirements to confirm hardware compatibility. Munki can't natively know if the device in question is capable of running the new operating system, so it will try in all cases but fail on unsupported hardware.
- macOS 11.0 (Big Sur) System Requirements
- macOS 10.15 (Catalina) System Requirements
- macOS 10.14 (Mojave) System Requirements
- macOS 10.13 (High Sierra) System Requirements
Next, check vendor resources to confirm that all vital software on the device is compatible with the new OS.
When ready, make the upgrade available by adding it to the Mac's serial number manifest as either an optional install or a managed install. (See our article on Munki manifests for guidance on editing manifests.)
- For an optional install, the upgrade will appear in Managed Software Center in multiple locations, but most notably on the 'Updates' tab in the 'Other available updates' section, where it can be selected at a time convenient to the end user. The ~5 GB installer won't be downloaded until the upgrade is selected.
Selecting the optional install will present a pre-upgrade alert in Managed Software Center, along with an option to cancel the selection and return the upgrade to its former optional status:
- For a managed install, the 5-12 GB installer will be downloaded and then offered on the 'Updates' tab in Managed Software Center the next time Munki runs after the manifest is modified, usually within an hour or two as long as the device has a network connection. It will not present the pre-upgrade alert; and as with any other managed install, it will block all other pending and future software updates until it is run. For this reason, optional installs may be a better choice than managed installs in situations when the end user will be performing the upgrade.
As indicated in Managed Software Center, OS upgrades (whether optional or managed) do require a restart and a wired connection (as most wifi connections do not persist after logout), and may take up to several hours to complete, depending on the age of the hardware and the type of hard drive. Upgrades on newer Macs with SSDs will take considerably less time to complete. As with any macOS upgrade, there is always a possibility that the upgrade process may hang, become caught in a restart loop, or otherwise fail to succeed. For this reason, it's best to schedule upgrades when the Mac is on campus, or when it can be brought to campus if post-upgrade support is required.