The Redfish® telemetry service
As per the DMTF Redfish telemetry whitepaper, the standard telemetry service allows clients to:
- Obtain the characteristics and details of a metric (metadata).
- Specify metric reports that periodically report a set of metrics (aggregation).
- Specify trigger thresholds against a metric that is monitored (monitoring).
NOTE
As this service is dependent of the computer chipset (Intel, AMD, ARM...) it may not be present in all types of servers.
When implemented, the telemetry entry point
URI
is /redfish/v1/TelemetryService
.
Metric reports can be stored locally, sent remotely or both.
Subscribing for metric reports
Metric reports can be sent remotely toward an event listener after an
event subscription
with EventFormatType=MetricReport
.
The following example shows a metric report subscription toward an HPE iLO 6.
POST /redfish/v1/EventService/Subscriptions/
{
"Destination": "https://myeventreciever/eventreceiver",
"EventFormatType": "MetricReport",
"MetricReportDefinitions": [
"/redfish/v1/TelemetryService/MetricReportDefinitions/CPUUtil",
"/redfish/v1/TelemetryService/MetricReportDefinitions/CPU0Power",
"/redfish/v1/TelemetryService/MetricReportDefinitions/CPU1Power"
],
"HttpHeaders": {
"Header1": "HeaderValue1"
},
"Context": "context string",
"Oem": {
"Hpe": {
"DeliveryRetryIntervalInSeconds": 30,
"RequestedMaxEventsToQueue": 20,
"DeliveryRetryAttempts": 5,
"RetireOldEventInMinutes": 10
}
}
}
Subscribed metric reports can be sent to the event listener periodically
only when MetricReportDefinitionType
property of the metric report
definition URI is set to Periodic
. In the cases of OnRequest
or OnChange
streaming will be stopped. This is defined in the MetricReportDefinitionType
property of the metric report definition
URI
for each metric report that is eligible to subscription.
The following example sets the frequency of the CPUUtil
metric report
of an HPE iLO 6 to 1 day (P1DT), starting on a specific day and GMT time.
PATCH /redfish/v1/TelemetryService/MetricReportDefinitions/CPUUtil/
{
"MetricReportDefinitionType": "Periodic",
"Schedule": {
"RecurrenceInterval": "P1DT",
"InitialStartTime": "2023-06-01T01:00:00Z"
}
}
Refer to this documentation section for examples and detail concerning the implementation of the Redfish® Telemetry service in HPE iLO 5 and iLO 6.