Jamf Pro Performance Tuning: Extension Attribute Audit

Before

The initial value of real was slightly more than 21 seconds for our Software Update Deferrals Extension Attribute script:

User dan is logged in
No new software available; Reset deferral counter
<result>1; No new software available.</result>

real	0m21.099s
user	0m0.027s
sys	 0m0.071s

“Tuned” Snippet

We followed Graham’s recommendation, assigning the value of LastRecommendedUpdatesAvailable to the availableUpdates variable:

availableUpdates=$( defaults read /Library/Preferences/com.apple.SoftwareUpdate.plist LastRecommendedUpdatesAvailable )

if [ "$availableUpdates" = "0" ]; then

   # No new software available

    …

else

    # Kickstart Software Update process
    launchctl kickstart -k system/com.apple.softwareupdated

    …

fi

After

During this run, the macOS-generated value of LastRecommendedUpdatesAvailable is zero, so execution time is improved by more than 234 times (i.e., reading the value of a client-side .plist vs. executing softwareupdate --list).

User dan is logged in
No new software available; Reset deferral counter
<result>1; No new software available.</result>

real	0m0.090s
user	0m0.006s
sys	 0m0.032s

1. View the API Documentation options by appending /api after your Jamf Pro server address
2. Locate the Classic API option and click View

3. Enter your Jamf Pro server credentials and click Authorize

4. Confirm you observe Authorized. Token successfully generated!

1. From the alphabetical list of endpoints, locate computerextensionattributes, click its disclosure triangle, then click Try it out

2. Click Execute to run the selected command

3. Click Download to save the results as XML

4. Right-click the downloaded file and select Open With > Microsoft Excel.

Observe the output of the following command — which requires elevated privileges — and take note of any Extension Attribute scripts which appear to have long execution times (i.e., “Running script for the extension attribute …” is displayed for multiple seconds).

time -p jamf recon -verbose

When the command completes, record the value of real as your initial baseline.

time -p jamf recon -verbose

…

 verbose: Running script for the extension attribute …

…

 verbose: Gatekeeper status: App Store and identified developers

…

real 369.14
user 125.40
sys   62.48

Generate a Jamf Pro Summary for only Computer Extension Attributes:

1. Jamf Pro >
2. Settings >
3. Jamf Pro Summary >
4. Select All >
5. Unselect All >
6. Computer Management – Management Framework >
7. Computer Extension Attributes >
8. Create >
9. Download

Open the dowloaded file in Visual Studio Code.

Use Visual Studio Code’s integrated Terminal to create a temporary eaTest.sh script in your Downloads folder, which you’ll use to test each of your Extension Attribute scripts:

1. touch ~/Downloads/eaTest.sh
2. chmod a+x ~/Downloads/eaTest.sh
3. Hold down the Option key to “Split Down” the current editor

4. Open ~/Downloads/eaTest.sh in the split window

1. For each Extension Attribute, copy-pasta the Mac Script code from the Jamf Pro Summary to the eaTest.sh file and save
2. In Code’s integrated Terminal, execute the following command:
   clear ; time -p ~/Downloads/eaTest.sh
3. Note the value of real

After downloading and populating the Jamf Pro Extension Attribute Audit Excel Template with your list of Extension Attributes, complete the following steps:

1. Assign a Criticality value for each Extension Attribute (i.e., How critical* is this Extension Attribute to your Jamf Pro policies?)
   • High
   • Med
   • Low
2. Record the value of real in the Original Time column
3. After you’ve “tuned” your Extension Attribute script, record the value of real in the Tuned Time column
4. Consider the risks and rewards of reducing the execution frequency for an Extension Attribute and assign one of three options in the Reduced Frequency column:
   • • In Process
   • √ Complete
   • X Delete
5. Review the impact of completely disabling a script-based Extension Attribute and update the Disabled column:
   • • In Process
   • √ Complete
   • X Delete
6. Use the Deleted column to ask yourself: “Would deleting this Extension Attribute — and any associated Smart Groups — negatively impact my Jamf Pro policies?”
   • • In Process
   • √ Complete
   • X Delete

Repeat Steps 1 through 6 for each Extension Attribute.

*In theory, every Extension Attribute is highly critical to your Jamf Pro environment — at least all of them were when you first created them.

In practice, regularly auditing your Extension Attributes comes with the gift of hindsight and allows you to make informed decisions about what you actually need and what you can do without.