Troubleshoot your IoT Edge for Linux on Windows device

Article
03/27/2024

Applies to: IoT Edge 1.4

Important

IoT Edge 1.4 is the supported release. If you are on an earlier release, see Update IoT Edge.

If you experience issues running Azure IoT Edge for Linux on Windows (EFLOW) in your environment, use this article as a guide for troubleshooting and diagnostics.

You can also check IoT Edge for Linux on Windows GitHub issues for a similar reported issue.

Isolate the issue

Your first step when troubleshooting IoT Edge for Linux on Windows should be to understand which component is causing the issue. There are three main components an EFLOW solution:

Windows components: PowerShell module, WSSDAgent & EFLOWProxy
CBL Mariner Linux virtual machine
Azure IoT Edge

For more information about EFLOW architecture, see What is Azure IoT Edge for Linux on Windows.

If your issue is installing or deploying the EFLOW virtual machine, make sure that all the prerequisites are met, and verify your networking and VM configurations. If your installation and deployment was successful and you're facing issues with the post VM management, the problems are generally related to VM lifecycle, networking, or Azure IoT Edge. Finally, if the issue is related to modules or IoT Edge features, check Troubleshoot your IoT Edge device.

For more information about common errors related to installation and deployment, provisioning, interaction with the VM, and networking, see Common issues and resolutions for Azure IoT Edge for Linux on Windows.

Gather debug information

When you need to gather logs from an IoT Edge for Linux on Windows device, the most convenient way is to use the Get-EflowLogs PowerShell cmdlet. By default, this command collects the following logs:

eflowlogs-summary.txt: contains the status of all log collection steps.
EFLOW VM configuration: includes the VM, networking, and passthrough configurations and additional information.
EFLOW Events : Windows events related to the VM lifecycle and EFLOWProxy service.
IoT Edge logs: includes the output of iotedge check the IoT Edge runtime support bundle.
WSSDAgent logs: includes all the logs related to the WSSDAgent service.

After the cmdlet gathers all the required logs, the files are compressed into a single file named eflowlogs.zip under the EFLOW installation path (For example, C:\Program Files\Azure IoT Edge).

Check your IoT Edge version

If you're running an older version of IoT Edge for Linux on Windows, then upgrading may resolve your issue. To check the EFLOW version installed on your device, use the following steps:

Open Settings on Windows.
Select Add or Remove Programs.
Depending on the EFLOW release train being used (Continuous Release or LTS), choose Azure IoT Edge LTS or Azure IoT Edge.
Check the version under the EFLOW app name.

For more information about specific versions release notes, check Azure IoT Edge for Linux on Windows release notes.

For instructions on how to update your device, see Update IoT Edge for Linux on Windows.

Check the EFLOW VM status

You can verify the EFLOW VM status and information by using the Get-EflowVm PowerShell cmdlet. If the EFLOW VM is running, the VmPowerState output should be Running. Whereas if the VM is stopped, the VmPowerState output is Off. To start or stop the EFLOW VM, use the Start-EflowVm and Stop-EflowVm cmdlet.

If the VM is Running but you can't interact or access the VM, there's probably a networking issue between the VM and the Windows host OS. Also, make sure that the EFLOW VM has enough memory and storage available to continue with normal execution. Run the Get-EflowVm cmdlet to see the memory(TotalMemMb, UsedMemMb, AvailableMemMb) and storage(TotalStorageMb, UsedStorageMb, AvailableStorageMb) information.

Finally, if the VM is Off and you can't start it using the Start-EflowVm cmdlet, there may be several reasons why the VM can't be started.

First, the issue could be related to the VM lifecycle management service (WSSDAgent) not running. Ensure that the WSSDAgent service is running using the following steps:

Start an elevated PowerShell session using Run as Administrator.
Check the service status
```
Get-Service -Name WSSDAgent
```
If the service is Stopped, start the service using the following command:
```
Start-Service -Name WSSDAgent
```
If the service is Running, the issue is probably related to a networking misconfiguration or lack of resources to create the VM.

Second, the issue could be related to lack of resources. You can set the EflowVmAssignedMemory (-memoryInMb) and EflowVmAssignedCPUcores (-cpuCount) assigned to the VM during deployment using the Deploy-Eflow PowerShell cmdlet, or after deployment using the Set-EflowVm cmdlet. If these resources aren't available when trying to start the VM, the VM fails to start. To check the resources assigned and available, use the following steps:

Start an elevated PowerShell session using Run as Administrator.
Check the available memory. Ensure that the FreePhysicalMemory is greater than the EflowVmAssignedMemory.
```
Get-CIMInstance Win32_OperatingSystem | Select FreePhysicalMemory
```
Check the available CPU cores. Ensure that NumberOfLogicalProcessors is greater than EflowVmAssignedCPUcores.
```
 wmic cpu get NumberOfLogicalProcessors
```

Finally, the issue could be related to networking. For more information about EFLOW VM networking issues, see How to troubleshoot Azure IoT Edge for Linux on Windows networking.

Check the status of the IoT Edge runtime

The IoT Edge runtime is responsible for receiving the code to run at the edge and communicate the results. If IoT Edge runtime and modules aren't running, no code runs at the edge. You can check the runtime and module status using the following steps:

Start an elevated PowerShell session using Run as Administrator.
Check the IoT Edge runtime status. In particular, check if the service is Loaded and Active.
```
(Get-EflowVm).EdgeRuntimeStatus.SystemCtlStatus | Format-List
```
Check the IoT Edge module status. Check that all modules are running.
```
(Get-EflowVm).EdgeRuntimeStatus.ModuleList | Format-List
```

For more information about IoT Edge runtime troubleshooting, see Troubleshoot your IoT Edge device.

Check TPM passthrough

If you're using TPM provisioning by following the guide Create and provision an IoT Edge for Linux on Windows device at scale by using a TPM, you must enable TPM passthrough. In order to access the physical TPM connected to the Windows host OS, all the EFLOW VM TPM commands are forwarded to the host OS using a Windows service called EFLOWProxy. If you experience issues using DpsTpm provisioning, or accessing TPM indexes from the EFLOW VM, check the service status using the following steps:

Start an elevated PowerShell session using Run as Administrator.
Check the status of the EFLOWProxy service.
```
Get-Service -Name EFLOWProxy
```
If the service is Stopped, start the service using the following command:
```
Start-Service -Name EFLOWProxy
```
If the service won't start, check the EFLOWProxy logs. Go to Apps > Event Viewer > Applications and Services Logs > Microsoft > EFLOW > EFLOWProxy and check the logs.
If the service is Running then check the EFLOW VM proxy services. Start by connecting to the EFLOW VM.
```
Connect-EflowVm
```
From inside the EFLOW VM, check the TPM services are up and running.
```
sudo systemctl status tpm*
```
You should see the status and logs of four different services. The four services should be up and running.
1. tpm2-netns.service - TPM2 Network Namespace
2. tpm2-socat@2322.service - TPM2 Sandbox Service on Port 2322
3. tpm2-socat@2321.service - TPM2 Sandbox Service on Port 2321
4. tpm2-abrmd.service - TPM2 Access Broker and Resource Management Daemon
If any of these services is stopped or failed, restart all services using the following command:
```
sudo systemctl restart tpm*
```
Check the communication between the EFLOW VM and the EFLOWProxy service. If communication is working, you should see the RegistrationId and the TPM Endorsement Key as output from the following command:
```
sudo /usr/bin/tpm_device_provision
```

Check GPU Assignment

If you're using GPU passthrough, ensure to follow all the prerequisites and configurations outlined in GPU acceleration for Azure IoT Edge for Linux on Windows. If you experience issues using GPU passthrough feature, check the following steps:

First, start by checking your device is available on the Windows host OS.

Open Apps > Device Manager.
Go to Display Adapters and check that your GPU is in the list.
Right-click the GPU name and select Properties.
Check that the driver is correctly installed.

Second, if the GPU is correctly assigned, but still not being able to use it inside the EFLOW VM, use the following steps:

Start an elevated PowerShell session using Run as Administrator.
Connect to the EFLOW VM
```
Connect-EflowVm
```
If you're using a NVIDIA GPU, check the passthrough status using the following command:
```
sudo nvidia-smi
```
You should be able to see the GPU card information, driver version, CUDA version, and the GPU system and processes information.
If you're using an Intel iGPU passthrough, check the passthrough status using the following command:
```
sudo ls -al /dev/dxg
```
The expected output should be similar to:
```
crw-rw-rw- 1 root 10, 60  Sep  8 06:20 /dev/dxg
```
For more Intel iGPU performance and debugging information, see Witness the power of Intel® iGPU with Azure IoT Edge for Linux on Windows(EFLOW) & OpenVINO™ Toolkit.

Check WSSDAgent logs for issues

The first step before checking WSSDAgent logs is to check if the VM was created and is running.

Start an elevated PowerShell session using Run as Administrator.

On Windows Client SKUs, check the HCS virtual machines.

hcsdiag list

If the EFLOW VM is running, you should see a line that contains a GUID followed by wssdagent. For example:

2bd841e4-126a-11ed-9a91-f01dbca16d1e
    VM,                         Running, 2BD841E4-126A-11ED-9A91-F01DBCA16D1E, wssdagent

88d7aa8c-0d1f-4786-b4cb-62eff1decd92
    VM,                         SavedAsTemplate, 88D7AA8C-0D1F-4786-B4CB-62EFF1DECD92, CmService

On Windows Server SKUs, check the VMMS virtual machines

hcsdiag list

If the EFLOW VM is running, you should see a line that contains the <WindowsHostname-EFLOW> as a name. For example:

Name               State   CPUUsage(%) MemoryAssigned(M) Uptime           Status             Version
----               -----   ----------- ----------------- ------           ------             -------
NUC-EFLOW          Running 0           1024              00:01:34.1280000 Operating normally 9.0

If for some reason the VM isn't listed, that means that VM isn't running or the WSSDAgent wasn't able to create it. Use the following steps to check the WSSDAgent logs:

Open File Explorer.
Go to C:\ProgramData\wssdagent\log
Open the wssdagent.log file.
Look for the words Error or Fail.

Reinstall EFLOW

Sometimes, a system might require significant special modification to work with existing networking or operating system constraints. For example, a system could require complex networking configurations (firewall, Windows policies, proxy settings) and custom Windows OS configurations. If you tried all previous troubleshooting steps and still have EFLOW issues, it's possible that there's some misconfiguration that is causing the issue. In this case, the final option is to uninstall and reinstall EFLOW.

Next steps

Do you think that you found a bug in the IoT Edge for Linux on Windows? Submit an issue so that we can continue to improve.

If you have more questions, create a Support request for help.