IoT Edge Device in Offline Mode

Question

IoT Edge Device in Offline Mode

Dhanavath Vishnu 366

Hi SatishBoddu-MSFT, @LeelaRajeshSayana-MSFT

In my project we are having 4 IoT Edge modules, communication between those modules happen through API calls and edge hub routes. Presently I have deployed the modules on linux VM for testing. I want to test the offline mode scenario for this device, there are no gateways, all the modules are deployed on a single VM.

I have tried set a rule to keep the VM outbound ports to deny all condition. By this method, I have restarted the IoT edge system using sudo iotedge system restart this command makes the device connection state to the Disconnected, it reflects in IoT HUB twin.

After the above steps, the communication between the modules is lost, the module Client initialization is getting failed.

Any idea, how can we debug this scenario?

Thanks

D. Vishnu

LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-23T01:38:02.7533333+00:00

Hi @Dhanavath Vishnu Greetings! I am following up to see if you got a chance to review the below response. Please let us know if you have any additional questions or need further assistance.
Dhanavath Vishnu 366 Reputation points

2023-06-23T12:20:37.59+00:00

Hi @LeelaRajeshSayana-MSFT ,

Thanks for your response, I have tried the following method on my virtual machine, the VM status is becomes disconnected after running the mentioned commands (ifconfig eth0 down).

But the problem is, because of these commands I am not able to access the modules which are running inside the VM. For suppose in my use case I am having 4 modules, out of these 4 modules, one of the modules is a frontend (UI), through this UI Module entire system can accessible. While the VM is in connected state, using DNS and inbound port, I am able to create an URL to access the UI which is running as IoT Edge module on the virtual machine.

By running the 'ifconfig eth0 down' command, I could be able to make the VM offline, but can't access the inbound and outbound ports of the VM (as network access of VM is disabled), due to this I am not able to access the UI module of my project, to execute(run) the system in offline mode on virtual machine.

If the real hardware system is there to host our Edge modules, that is entirely different case, where we can intentionally disconnect the network cable to make the hardware to work in offline mode. In this you will be having physical access to run URL to verify the system running.

Can you suggest me alternative way to make the virtual machine to offline and that makes I can access the modules which are hosted on the VM.

I hope I have made my point clear, if not please let me know.

Thanks

D. Vishnu
LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-23T19:29:39.2933333+00:00

Hi @Dhanavath Vishnu Thank you for sharing additional details on what you are you are trying to achieve.

With the current approach, I am not sure if it is possible to have the UI module accessible and make the other modules go offline. A better approach to achieve this is by creating the UI module on a different edge device and make this device act as transparent gateway to the other three modules. Please refer this article How an IoT Edge device can be used as a gateway to get more details on this approach.
Dhanavath Vishnu 366 Reputation points

2023-06-26T12:16:34.0766667+00:00

Hello @LeelaRajeshSayana-MSFT ,

Thanks for your response.

I want to rephase my scenario:

The idea is, we want to make the virtual machine, where we have deployed, 4 IoT Edge Modules work in a offline mode. Actually, these modules are developed to run on Linux OS Hardware Device (IoT Edge Device), presently we don't have an access of hardware, we deployed them on Linux virtual machine for testing purposes.

Once the modules are deployed on virtual machine, we use the DNS + Inbound port combined URL, using a browser we run URL for verifying the different functionality implemented by the developers. These virtual machine ports are internally bind with the IoT Edge modules.

I have followed this training module provided by the microsoft,

https://learn.microsoft.com/en-us/training/modules/explore-iot-edge-offline-support/

In this as they mentioned, if we make virtual machines outbound port to deny all condition and run the command: iotedge sytem restart. The virtual machine goes in offline mode. After running this command, device status changes to Disconnected state, the IoT Edge runtime response shows 406 error code. I have tried same in my scenario, to make the virtual machine offline, during this I am getting errors such as:

ModuleClient instance initialization is getting failed, as I am using the AMQP protocol for this.

In this condition, using inbound ports I am able to access my URL, able to make the API calls between the modules, but the modules communication using the routes is getting failed.

I need your help in resolving this.

Thanks

D. Vishnu
LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-26T14:44:31.27+00:00

Hi @Dhanavath Vishnu Thank you for sharing additional information and the resource you have followed in setting up the test scenario.

For a deeper investigation and immediate assistance on this issue, please file a support request @ https://aka.ms/azsupt? If you do not have access to a support plan, could you please send an email to azcommunity@microsoft.com with the below details, so that we can work closely on this matter.

Thread URL: Link to this thread.
Azure Subscription ID:
Email Subject : Attn Leela

Accepted answer

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Your answer

LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-23T01:38:02.7533333+00:00

Hi @Dhanavath Vishnu Greetings! I am following up to see if you got a chance to review the below response. Please let us know if you have any additional questions or need further assistance.
Dhanavath Vishnu 366 Reputation points

2023-06-23T12:20:37.59+00:00

Hi @LeelaRajeshSayana-MSFT ,

Thanks for your response, I have tried the following method on my virtual machine, the VM status is becomes disconnected after running the mentioned commands (ifconfig eth0 down).

But the problem is, because of these commands I am not able to access the modules which are running inside the VM. For suppose in my use case I am having 4 modules, out of these 4 modules, one of the modules is a frontend (UI), through this UI Module entire system can accessible. While the VM is in connected state, using DNS and inbound port, I am able to create an URL to access the UI which is running as IoT Edge module on the virtual machine.

By running the 'ifconfig eth0 down' command, I could be able to make the VM offline, but can't access the inbound and outbound ports of the VM (as network access of VM is disabled), due to this I am not able to access the UI module of my project, to execute(run) the system in offline mode on virtual machine.

If the real hardware system is there to host our Edge modules, that is entirely different case, where we can intentionally disconnect the network cable to make the hardware to work in offline mode. In this you will be having physical access to run URL to verify the system running.

Can you suggest me alternative way to make the virtual machine to offline and that makes I can access the modules which are hosted on the VM.

I hope I have made my point clear, if not please let me know.

Thanks

D. Vishnu
LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-23T19:29:39.2933333+00:00

Hi @Dhanavath Vishnu Thank you for sharing additional details on what you are you are trying to achieve.

With the current approach, I am not sure if it is possible to have the UI module accessible and make the other modules go offline. A better approach to achieve this is by creating the UI module on a different edge device and make this device act as transparent gateway to the other three modules. Please refer this article How an IoT Edge device can be used as a gateway to get more details on this approach.
Dhanavath Vishnu 366 Reputation points

2023-06-26T12:16:34.0766667+00:00

Hello @LeelaRajeshSayana-MSFT ,

Thanks for your response.

I want to rephase my scenario:

The idea is, we want to make the virtual machine, where we have deployed, 4 IoT Edge Modules work in a offline mode. Actually, these modules are developed to run on Linux OS Hardware Device (IoT Edge Device), presently we don't have an access of hardware, we deployed them on Linux virtual machine for testing purposes.

Once the modules are deployed on virtual machine, we use the DNS + Inbound port combined URL, using a browser we run URL for verifying the different functionality implemented by the developers. These virtual machine ports are internally bind with the IoT Edge modules.

I have followed this training module provided by the microsoft,

https://learn.microsoft.com/en-us/training/modules/explore-iot-edge-offline-support/

In this as they mentioned, if we make virtual machines outbound port to deny all condition and run the command: iotedge sytem restart. The virtual machine goes in offline mode. After running this command, device status changes to Disconnected state, the IoT Edge runtime response shows 406 error code. I have tried same in my scenario, to make the virtual machine offline, during this I am getting errors such as:

ModuleClient instance initialization is getting failed, as I am using the AMQP protocol for this.

In this condition, using inbound ports I am able to access my URL, able to make the API calls between the modules, but the modules communication using the routes is getting failed.

I need your help in resolving this.

Thanks

D. Vishnu
LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-26T14:44:31.27+00:00

Hi @Dhanavath Vishnu Thank you for sharing additional information and the resource you have followed in setting up the test scenario.

For a deeper investigation and immediate assistance on this issue, please file a support request @ https://aka.ms/azsupt? If you do not have access to a support plan, could you please send an email to azcommunity@microsoft.com with the below details, so that we can work closely on this matter.

Thread URL: Link to this thread.
Azure Subscription ID:
Email Subject : Attn Leela

Answer 1

Hi @Dhanavath Vishnu Thank you for posting this question here.

I believe this behavior you see is expected when you disable all outbound network ports on the VM. The Edge Hub module is responsible for module-to-module communication established using the routes. These communications work on ports 8883 (MQTTS) or 5671 (AMQPS) or 443(TLS) if using API. Hence all the routing and communication would be down when all outbound network ports all closed.

An alternate/ideal way to test the offline capability of the IoT Edge device is by disabling just the network access to the host VM rather than closing all the ports. You can disable the network access to an Azure hosted VM by running the command ifconfig eth0 down. This will disable the netwokk connectivity to the device and forces it to operate in offline mode. You can later enable network access by connecting to serial console of the VM and use ifconfig eth0 up command to restore connectivity.

Hope this helps. Please let us know if you have any additional questions or need further clarifications on this.

If the response helped, please do click Accept Answer and Yes. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.

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IoT Edge Device in Offline Mode

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