Target Mode Imaging

Target Mode Imaging (TMI) allows you to image multiple computers by connecting them to a host computer using a FireWire, Thunderbolt, or USB-C cable. This can be ideal when using a network connection is not optimal or supported.

To use TMI, you run Jamf Imaging on a host computer. Then you boot the computers being imaged (target computers) to target disk mode and connect them to the host computer.

This section provides a basic, best practice workflow for imaging computers using TMI.

Best practices for TMI differ based on the scope of the project. Consider the following when planning your TMI project:

  • Number of staff available

  • Number of target computers

  • Number of host computers available

  • Time constraints
    Note: It is recommended that you set up a test environment prior to the project's start date to help estimate how long it will take to complete the project in each unique environment.

Requirements

To use TMI, you need:

  • Target computers that support target disk mode

  • A host computer with Jamf Imaging installed and a FireWire, Thunderbolt, or USB-C port
    Note: It is recommended that you use a dedicated host computer for TMI.

  • A configuration with a base image and packages
    If you have not created the configuration or base image yet, see "Create a Configuration with a Base Image and Packages" in Target Mode Imaging for detailed instructions.

  • A distribution point
    While you can use a file share distribution point on the network, it is recommended that you use a local distribution point for optimal data transfer speeds. (For detailed instructions, see "Create a Local Distribution Point" in Target Mode Imaging.)

  • A Thunderbolt to Thunderbolt cable, FireWire cable, or USB-C cable

  • A naming scheme (For more information, see "Naming Scheme" in Target Mode Imaging.)

Before You Begin

The following instructions will help you prepare for imaging.

Note: If asset stickers need to be applied to new computers, consider applying them during the TMI project.

Create a Configuration with a Base Image and Packages

Configurations allow you to quickly specify what needs to be installed and configured on computers during imaging. Configurations can be created using Jamf Pro or Jamf Admin.

Note: It considered best practice to use configurations when imaging computers using TMI. However, if you are not using configurations, click Show Custom in Jamf Imaging and then use the tabs and options to customize the imaging process.

If you need a base OS image, see the Creating a Minimal Base OS Image article for detailed instructions.

Using Jamf Pro to Create a Configuration

  1. Log in to Jamf Pro.

  2. In the top-right corner of Jamf Pro, click Settings images/download/thumbnails/82686254/Icon_Settings_Hover.png .

  3. Click Computer Management.

  4. In the "Computer Management" section, click Configurations.

  5. Click New images/download/thumbnails/82686254/Icon_New_Button.png .

  6. Use the General payload to configure basic settings for the configuration.

  7. Use the Packages, Scripts, Printers, and Directory Bindings payloads to add items to the configuration.

  8. Use the Management payload to set or create a management account.
    This ensures that computers imaged with the configuration are managed.

  9. Click Save.

Using Jamf Admin to Create a Configuration

  1. Open Jamf Admin on the host computer.

  2. Select "New Config".

  3. Enter basic configuration information.

  4. Click Save.

  5. Drag packages from the right pane to the configuration in the sidebar.

For more information, see Configurations in the Jamf Pro Administrator's Guide.

Create a Local Distribution Point

A local distribution point created on the host computer can greatly increase the efficiency and speed of the imaging process.

  1. Create a new folder in the root of the host computer's main hard disk.

  2. Open Jamf Admin on the host computer.

  3. Drag a folder from the host computer into the sidebar of Jamf Admin.

  4. Select the folder in the sidebar and click Replicate.
    Note: The entire distribution point will be replicated to the host computer's drive. Be aware of available space on the drive.

  5. When replication to the local folder is complete:

    1. Select "Choose Local Drive" from the Distribution Point pop-up menu in Jamf Imaging and browse to the Local Distribution Point folder.

    2. Click Choose.

  6. In the main Jamf Imaging window, verify that the Distribution Point displays the path to the Local Distribution Point folder.

Naming Scheme

You can use Jamf Imaging to specify how to assign names to target computers when imaging computers using TMI.

  1. Open Jamf Imaging on the host computer.

  2. From the Computer Names pop-up menu, choose how to assign names to target computers:

    • To be prompted to manually enter a name for each computer, choose "Prompt for Each Computer".

    • To automatically generate names in numerical order, choose "Use Numerical Order". Then enter a starting number, and a prefix and suffix as needed, and click OK.

    • To use each computer's MAC Address as the name, choose "Use MAC Address". Then enter a prefix and suffix for the MAC Address as needed and click OK.

    • To use each computer's serial number as the name, choose "Use Serial Number". Then enter a prefix and suffix for the serial number as needed and click OK.

    • To assign names based on the contents of a CSV file, choose "Upload CSV File" and upload the file.
      For more information, see Creating a CSV File to Assign Computer Names During Target Mode Imaging.

Imaging Computers

You can use TMI to image a single target computer or multiple target computers.

Imaging a computer involves the following steps:

  1. Prepare the host computer.

  2. Image the target computer.

Step 1: Prepare the Host Computer

  1. Ensure no computers are connected to the host computer.

  2. On the host computer, open Jamf Imaging and authenticate locally.

  3. Authenticate to the Jamf Pro server when prompted.

  4. Choose “Target Mode Imaging” from the Target Drive pop-up menu.

  5. Choose the naming scheme from the Computer Names pop-up menu.

  6. Choose a configuration from the Configuration pop-up menu.

  7. Choose the distribution point from the Distribution Point pop-up menu.

  8. From the Computers Will Check In with JSS pop-up menu, choose the approximate amount of time until computers check in with Jamf Pro.
    This sets the expiration value of the enrollment invitation.
    Important: For the enrollment process to complete, computers will need to be connected to a network that can acesss Jamf Pro. Select a larger value if you are unsure how long it will take for the computers to get a connection and check in with Jamf Pro. If the enrollment window expires before computers check in, those computers will need to be enrolled in Jamf Pro using a different method.

Step 2: Image the Target Computer

  1. Verify the settings are correct in Jamf Imaging and click Start .
    Warning: Jamf Imaging begins to look for connected computers at this point.

  2. Boot a target computer to target disk mode.
    To do this, turn on the computer and immediately press and hold down the T key until a FireWire, Thunderbolt, or USB-C symbol is displayed.

  3. Use a FireWire, Thunderbolt, or USB-C cable to connect the target computer to the host computer, and then click OK if prompted.
    The imaging process starts immediately.
    If configured to prompt for computer name, Jamf Imaging prompts for the new computer name.

  4. When the imaging process is complete, disconnect the target computer.
    The target computer will attempt to connect to Jamf Pro at startup and then every five minutes until it successfully enrolls the computer.

Post-imaging Enrollment

After target computers have been imaged, they can be stored or turned on.

If a computer is not able to connect to the Jamf Pro server before the enrollment window specified in the Computers Will Check In with JSS pop-up menu expires, those computers will need to be enrolled in Jamf Pro using a different method.

If the computers are stored immediately, they are not enrolled with Jamf Pro until the next time they are turned on and connected to a network that can access Jamf Pro. Any issues enrolling computers with Jamf Pro will not be discovered until the day of the rollout, and must be resolved at that time. This method completes the TMI process in the fastest time.

If the computers are immediately turned on and are connected to a network with access to Jamf Pro, they are automatically enrolled with Jamf Pro and successful enrollment can be verified. Using this method, it is possible to verify that the computers are fully prepared for the rollout day.

Troubleshooting

Target computers not detected by Jamf Imaging

If target computers are not detected during the "Searching for Computers" phase:

  1. Verify that both computers have ports supported by target disk mode and are target disk mode compatible. For more information about the types of ports and cables that support target disk mode connections, see the following article from Apple's support website: https://support.apple.com/HT201462

  2. Unplug the cable from the target computer, wait 10 seconds, and then re-insert the cable.

Note: A variety of issues may occur if imaging is done on multiple target computers in succession using a single host computer. Regularly scheduled reboots after imaging 2-5 target computers can help resolve imaging issues that arise. The number of target computers that can be imaged between reboots can vary based on the host computer.

Packages missing from the imaged computer

If packages are missing or don't deploy during imaging:

  1. Verify the packages are listed on the sidebar of Jamf Imaging prior to clicking "Image".

  2. To determine whether a specific package is causing the issue: Deploy the package to a test computer that is not part of the imaging process and ensure the intended results are achieved.

  3. Use Jamf Pro to check the Jamf Imaging logs for the target computer.
    For more information, see "Viewing Jamf Imaging Logs for a Computer" on the Computer History Information page in the Jamf Pro Administrator's Guide.

Jamf Imaging Debug Mode

If you are not able to resolve TMI issues, put Jamf Imaging into full debug mode and contact your Jamf account representative. Putting Jamf Imaging into debug mode will help your Jamf account representative identify the issue. To put Jamf Imaging into full debug mode, execute the following command on the host computer and then reopen Jamf Imaging:

sudo touch /Applications/Jamf\ Pro/Jamf\ Imaging.app/Contents/Support/debug

For more information about enabling debug mode, see the Enabling Debug Mode article.

When full debug is enabled in this way, a log is created on the target computer. This log can be found in the following location:

/Library/Logs/JAMF/ImagingScripts.log

A debug log is also created on the host computer running Jamf Imaging. This log can be found in the following location:

~/Library/Logs/JAMF/CasperImagingDebug.log

Logs and any screenshots of the issue are also helpful. From the target computer, the logs to provide are:

  • /var/log/system.log

  • /var/log/jamf.log

  • /var/log/install.log

From the Jamf Pro server, the log to provide is:

/path/to/jss/logs/JAMFSoftwareServer.log

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