Exam AZ-220 topic 1 question 13 discussion

Actual exam question from Microsoft's AZ-220

Question #: 13
Topic #: 1

You have 100 devices that connect to an Azure IoT hub named Hub1. The devices connect by using a symmetric key.
You deploy an IoT hub named Hub2.
You need to migrate 10 devices from Hub1 to Hub2. The solution must ensure that the devices retain the existing symmetric key.
What should you do?

A. Add a desired property to the device twin of Hub2. Update the endpoint of the 10 devices to use Hub2.
B. Add a desired property to the device twin of Hub1. Recreate the device identity on Hub2.
C. Recreate the device identity on Hub2. Update the endpoint of the 10 devices to use Hub2.
D. Disable the 10 devices on Hub1. Update the endpoint of the 10 devices to use Hub2.

Show Suggested Answer

Suggested Answer: B 🗳️
Desired properties. Used along with reported properties to synchronize device configuration or conditions. The solution back end can set desired properties, and the device app can read them. The device app can also receive notifications of changes in the desired properties.
Reference:
https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-device-twins

by BoomJosh at March 24, 2021, 7:26 p.m.

Comments

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pdeng

2 years, 6 months ago

I would go for C. The assumption is the connection string is hard-coded in device.

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Robert12345Robert

2 years, 9 months ago

tricky question, the endpoint is not changing by itself, you should do some programming on the device to support this. That is why I think answer C is the better and more accurate.

upvoted 3 times

hotwheelsinsf

2 years, 4 months ago

lots more working re-defining the endpoints....

upvoted 1 times

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classicryder

3 years, 1 month ago

why not A?

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d0bermannn

3 years, 5 months ago

Selected Answer: B

nice question, that is the point where dev.twin must be used

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tita_tovenaar

4 years ago

should be B. scenario is mentioned in following doc: https://docs.microsoft.com/en-us/azure/iot-dps/how-to-reprovision

upvoted 2 times

d0bermannn

3 years, 6 months ago

your link have another option, but B still correct, as there are many ways to skin a cat)

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JeeBi

4 years, 1 month ago

When creating a device, you can provide the symmetric keys. So I would go for answer C: recreate the devices using the same keys and the change the endpoint.

upvoted 3 times

jracabrera

4 years, 1 month ago

Thanks JeeBi. I think you are right about recreate the device using the same keys. But, in real life, instead go to 10 devices and change the endpoint, you would use the the twin desired properties for your devices to consume the IoT Hub host name. In that way you can use Hub2. For me, the better is option B.

upvoted 4 times

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