IoT Rule on Greengrass Core Device Health Status

Question

I am trying to set up an IoT rule for when a Greengrass V2 core devices' health changes.  Looking at the source code for GGV2, it shows that the device will publish to the topic `$aws/things/{thingName}/greengrassv2/health/json` to report health status.  I've tried using that topic in the MQTT test client, but do not see any activity when I force my device to be unhealthy.  Is there another way to hook in to that functionality, or any documentation of topics that are available to the test client or IoT rules?

Answer

Hi rchamberlin. The core device publishes both core device health (fleet status) and telemetry data on that topic. However that topic is not exposed on the broker so you can't subscribe to it. Furthermore, this information is only published every 24 hours (by default, and this is the minimum interval), not in response to events. Please see the fleetStatus and telemetry configuration parameters of the Greengrass Nucleus configuration for more information: https://docs.aws.amazon.com/greengrass/v2/developerguide/greengrass-nucleus-component.html#greengrass-nucleus-component-configuration

For more frequent telemetry, you might consider the telemetry emitter component:

EXPERT

Greg_B

answered 2 years ago

For more frequent telemetry, you might consider the telemetry emitter component:
- https://docs.aws.amazon.com/greengrass/v2/developerguide/nucleus-emitter-component.html
- https://docs.aws.amazon.com/greengrass/v2/developerguide/telemetry.html

Answer

Hi! Is this 24 hour minimum limit something you could consider changing? It would be very convenient to use the Health status in the dashboards to check whether a unit is ok or not! Now I sometimes find myself confused by it, for example when trying to deploy new code to a "Healthy" unit that isn't currently connected to AWS at all etc.

IoT Rule on Greengrass Core Device Health Status

Relevant content