Creates a launch daemon and script on target Macs in a Jamf Pro policy to download the specified macOS installer and update Jamf Pro's inventory. This is preferable to running a command directlt in policy, which can take 30+ minutes to complete, preventing other policies from running. The script self destructs once it sees the installer in the A…

Download macOS Monterey in Background.zsh

#!/bin/zsh

:<<ABOUT_THIS_SCRIPT
-------------------------------------------------------------------------------

	Written by:William Smith
	Partner Program Manager
	Jamf
	bill@talkingmoose.net
	https://gist.github.com/6b78ba3fc4a6623dbc8225e2df38d570
		
	Originally posted: April 16, 2022

	Purpose: Creates a launch daemon and script on target Macs in a Jamf Pro policy
	to download the specified macOS installer and update Jamf Pro's inventory.
	This is preferable to running a command directlt in policy, which can take 30+
	minutes to complete, preventing other policies from running. The script self
	destructs once it sees the installer in the Applications folder.
	
	Instructions:
	
	1. Create a new script in Jamf Pro named "Download macOS Monterey in Background".
	
	2. Paste the entire contents of this script as-is into the Script field.
	
	2. Under Options, set the following parameter labels:
	Parameter 4 = "macOS Version (e.g., '12.3.1')"
	Parameter 5 = "Organization Name" (e.g., 'Talking Moose Industries')
	Parameter 6 = "Organization Reverse Domain" (e.g., 'net.talkingmoose')
	
	3. Add the script to a policy and set the three parameters.
	
	4. Enable the policy for Recurring Check-In Once Per Computer.
	
	5. Scope the policy to target Macs that meet the specifications to run the
	downloaded installer and exclude Macs that already have the installer downloaded.
	
	As soon as a computer checks-in and completes the policy, the launch daemon
	will start the download, which may take 20+ minutes to complete. The launch
	daemon will attempt to download every hour until successful.

	Except where otherwise noted, this work is licensed under
	http://creativecommons.org/licenses/by/4.0/

	"If you lie down with dogs, you get up with fleas."
	— Lucius Annaeus Seneca the Elder
	
-------------------------------------------------------------------------------
ABOUT_THIS_SCRIPT


macOSVersion="$4"
organizationName="$5"
organizationReverseDomain="$6"

# create organization folder if necessary to house the script

/bin/mkdir -p "/Library/$organizationName"

# create fetch-full-installer.zsh script

tee /Library/$organizationName/fetch-full-installer.zsh << EOF
#!/bin/zsh

# if 'Install macOS Monterey.app' exists in the Applications folder, self destruct

if [ -e '/Applications/Install macOS Monterey.app' ]; then
	
	# delete this script
	/bin/rm "/Library/$organizationName/fetch-full-installer.zsh"
	
	# attempt to delete enclosing directory
	/bin/rmdir "/Library/$organizationName"
	
	# delete the launch daemon plist
	/bin/rm "/Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist"
	
	# kill the launch daemon process
	/bin/launchctl remove $organizationReverseDomain.fetch-full-installer
	
	exit 0
fi

# download the specified version of "Install macOS Monterey.app"
/usr/sbin/softwareupdate --fetch-full-installer --full-installer-version "$macOSVersion"

# update Jamf Pro inventory after downloading 'Install macOS Monterey.app'
/usr/local/bin/jamf recon

exit 0
EOF

# report to policy whether script was created

if [ $? = 0 ]; then
	echo "Creating script at \"/Library/$organizationName/fetch-full-installer.zsh\""
else
	echo "Failed creating script at \"/Library/$organizationName/fetch-full-installer.zsh\""
fi

# set correct ownership and permissions on categorize-policies.bash script

/usr/sbin/chown root:wheel "/Library/$organizationName/fetch-full-installer.zsh" && /bin/chmod +x "/Library/$organizationName/fetch-full-installer.zsh"

# report to policy whether ownership and permissions were set

if [ $? = 0 ]; then
	echo "Setting correct ownership and permissions on \"/Library/$organizationName/fetch-full-installer.zsh\" script"
else
	echo "Failed setting correct ownership and permissions on\"/Library/$organizationName/fetch-full-installer.zsh\" script"
fi

# create $organizationReverseDomain.fetch-full-installer.plist launch daemon

tee /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist << EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>EnvironmentVariables</key>
	<dict>
		<key>PATH</key>
		<string>/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin</string>
	</dict>
	<key>Label</key>
	<string>$organizationReverseDomain.fetch-full-installer</string>
	<key>ProgramArguments</key>
	<array>
		<string>/bin/zsh</string>
		<string>-c</string>
		<string>"/Library/$organizationName/fetch-full-installer.zsh"</string>
	</array>
	<key>RunAtLoad</key>
	<true/>
	<key>StartInterval</key>
	<integer>3600</integer>
</dict>
</plist>
EOF

# report to policy whether plist was created

if [ $? = 0 ]; then
	echo "Creating launch daemon at /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist"
else
	echo "Failed creating launch daemon at /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist"
fi

# set correct ownership and permissions on launch daemon

/usr/sbin/chown root:wheel /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist && /bin/chmod 644 /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist

# report to policy whether ownership and permissions were set

if [ $? = 0 ]; then
	echo "Setting correct ownership and permissions on launch daemon"
else
	echo "Failed setting correct ownership and permissions on launch daemon"
fi

# start launch daemon after installation

/bin/launchctl bootstrap system /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist && /bin/launchctl start /Library/LaunchDaemons/$organizationReverseDomain.fetch-full-installer.plist

# report to policy whether launch daemon was started

if [ $? = 3 ]; then
	echo "Starting launch daemon"
else
	echo "Failed starting launch daemon"
fi

exit 0

You set "$macOSVersion", but it never gets used. The place it should be used instead recalls $4 from the args.

Maybe passing an empty value for $4 should cause it to call softwareupdate --fetch-full-installer without the --full-installer-version. That way it would simply grab the latest version.

Is there a way we can tell if download is happening in the background? I'm noticing the launch daemon shows no PID # and has a error of 127.

@duff2481, look for the sofwareupdate command. The launch daemon is just a settings file and won’t have its own PID.

I’m happy to c if in case old version exists I do not think so it’s validated with new or defined version?