CODEWITHSUNDEEP
azureazure-iot-hubazure-iot-edge
Mehdi Benmoha
Mehdi Benmoha

Reputation: 3945

Events not replayed when certificate expired azure iot hub edge

Context

An azure iot hub with an edge device configured to have a cache of 20 hours through ttl setting in edgeHub deployment template. The storage is also binded to a host folder in the container options.

Problems

The last days, there were some problems in our deployment pipeline, so the edgeHub configuration maybe have been lost ? ( I hope not because, the portal showed that the modules just get stuck with the last working version ), and after pipeline problems have been resolved, the device certificate expired. So we rebooted the device to generate new certificate, the down time was approximately 20 hours.

Question

After checking the telemetry messages rooted to a blob storage, there are no messages in that down time, so why the events didn't get replayed ? and how to prevent that from happening another time ?

Upvotes: 0

Views: 154

Answers (1)

asergaz
asergaz

Reputation: 1051

If you use IoT Edge Offline capabilities, the IoT Edge device, its deployed modules, and any child devices can operate indefinitely.

Because storage of messages depends on the time to live (TTL) setting and the available disk space for storing the messages, you will need to find the correct balance in your environment to avoid losing messages when you cannot reach IoT Hub for periods longer than 20hours.

Suggestion then is to increase TTL. The maximum value is only limited by the maximum value of an integer variable, which is around 2 billion seconds.

Reference: Understand extended offline capabilities for IoT Edge devices, modules, and child devices

Upvotes: 0

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