USB-Based System Replication for NI Linux Real-Time Targets

This article outlines the steps to replicate or install an image in a NI Linux Real-Time (RT) target using a USB drive. Before starting this process please consider the following:

• Only RT targets with NI Linux RT System Image 2024Q4 (24.8) and above are compatible with this replication method. 
• This process only applies to NI Linux RT targets with Intel x64 based architectures. You can verify whether your RT target is compatible with this method by reviewing this link: Real-Time Controllers and Real-Time Operating System Compatibility.
• The image replicated can be only installed in RT targets of the same model.
• Some settings such as Hostname, SSH keys, Salt Minion ID, that uniquely identify a target on a network are not replicated to prevent conflicts on the network.

With that said, make sure you have the following software and hardware ready before proceeding with the steps below:

• NI CompactRIO Driver 2024Q4 or later installed in your host PC, this one installs the NI Linux RT image files that will be used in this tutorial.
• USB drive (at least 8GB) with FAT32
• Monitor to connect to the RT target
• Keyboard to connect to the RT target

Preparing a USB Drive

1. Format a USB drive with FAT32 File System in Windows machine and set NIRECOVERY as Volume label.

2. Mount the nilrt-recovery-media-x64.iso located in the directory below: 
   1. C:\Program Files (x86)\National Instruments\RT Images\Utilities\Linux RT Safemode\<version 24.8 and above> 
3. Copy the contents to the USB drive.
   1. Do not write the entire iso file to the USB drive.
   2. Only nilrt-recovery-media-x64.iso included with version 24.8 and above of NI Linux RT System Image can be used to create a USB drive capable of system replication.

Getting an Image

The USB drive prepared in section "Preparing USB Drive" can be used to replicate a system image from an x64 NI Linux RT target. 

1. Connect the USB drive to the NI Linux RT target
2. Restart the target and boot to the USB drive, the boot order might need to be manually changed from the BIOS in order to boot from the USB drive.
   
   1. Press the <Delete> or <F10 key> while the target is restarting to enter the BIOS. 
   2. Use the keyboard to move to Boot Setup Menu and change the USB as first boot option.
3. When booting from the USB, the following menu appears, select the Get Image menu option.

4. Enter a name for the image (make sure there are no spaces or special characters except -) or accept the provided default name, for example "cRIO-9043-2024-06-05-19-01-38" as shown below.

5. Getting the image can take a few minutes depending on the amount of user data and write speed of the USB drive. The progress bar will keep moving to show progress.
   1. The tool will estimate if the available space on the USB drive will be sufficient to store the contents of all partitions. If there is insufficient space, an error will be displayed.

6. The image will be saved to the USB drive under D:\Images\<NameOfSystemImage>. 
7. When the operation is complete, the following prompt will be shown. The USB drive can then be removed. Type reboot, and press Enter to reboot the target.

Setting an Image

The USB drive prepared in section "Preparing USB Drive" can be used to apply a system image to an x64 NI Linux RT target.

1. Connect the USB drive to the NI Linux RT target
2. Restart the target and boot to the USB drive, the boot order might need to be manually changed from the BIOS in order to boot from the USB drive.
   
   1. Press the <Delete> or <F10 key> while the target is restarting to enter the BIOS. 
   2. Use the keyboard to move to Boot Setup Menu and change the USB as first boot option.
3. When booting from the USB, the following menu appears, select the Set Image menu option.
4. All images that are available on the USB drive and are compatible with the target will be listed. Select one by entering the corresponding number and press Enter.

5. Confirm to begin applying the specified image by entering y.

6. A progress bar will keep moving to show progress.

7. When the operation is complete, the following prompt will be shown. The USB drive can then be removed. Type reboot, and press Enter to reboot the target.

The USB-based system replication feature will allow saving the full disk image of an x64 based NI Linux RT capable target and applying it to same or different target(s) of the same model. This feature will replicate all disk contents, including safemode, runmode, drivers, other installed software, settings, and user files.

Next Steps

Using Provisioning Answers File

A file named ni_provisioning.answers can be placed in the root directory of the USB drive to disable interactive user prompts. Each prompt has a corresponding variable that can be set to the desired value. 

• Make sure the ni_provisioning.answers file is Unix Line Feed (LF) format, otherwise, the process will ignore the file settings.
  
  • If you do not have a way to change your ni_provisioning.answers file from Windows CRLF to Unix LF, feel free to use and modify the file attached in this article. 
• Do not modify anything in the file besides the settings between quotes (""), otherwise, the process will ignore the file settings.

For example:

• When “Get Image” is selected in the boot menu, the saved image will be named “NameOfSystemImage” and the target will be powered off after the image is made.
• When “Set Image” is selected in the boot menu, an image on the USB drive named “NameOfSystemImage” will be selected, the confirmation to repartition prompt will be confirmed, and the target will reboot after the image is applied.

Automating the USB Replication Process

In case you need to fully automate the process and avoid the user prompts you can follow the steps below:

Configuring USB:

1. Prepare your USB as described in "Prepare a USB Drive" section.
1. You must add your ni_provisioning.answers file in the USB to automate the user prompts.
2. You must have a previous configured image in D:\Images directory to set an image automatically.
2. Look for the grub.cfg file located in the USB directory: D:\EFI\BOOT\grub.cfg
3. Edit this file in line 2 and change the default setting to Get Image or Set Image as default option when launching the boot menu.

4. Eject the USB

Launching USB in cRIO controller:

1. Ensure the USB was configured with the steps above.
2. Turn OFF your RT target.
3. Plug the USB drive.
4. Press the RESET button while the RT target is OFF.
5. While pressing the RESET button, turn ON the RT target.
6. Keep pressing the RESET button until the STATUS LED turns ON and wait ~5 seconds more.
7. After the ~5 seconds the STATUS LED has turned ON, release the RESET button.
8. The RT target will start on the boot menu with the action you configured in the default parameter of the grub.cfg file.
9. The RT target will start the default selected process and run automatically the user prompts using the ni_provisioning.answers file.