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IPMI Java Client 2.0.00

Sensors

The BMC describes its sensors in the Sensor Data Record (SDR) repository: one record per sensor, with its name, what it measures (the entity: a processor, a power supply, the system board, …), its unit, the formula that converts its raw reading, and its thresholds. The client walks this repository and reads the sensors that have a reading.

try (IpmiClient bmc = IpmiClient.builder(host).credentials(user, password).build()) {
	for (Sensor sensor : bmc.sensors().execute()) {
		System.out.println(sensor);
	}
}

How the sensors are read

sensors().execute()[1]:

  1. walks the SDR repository from the first record to the last with Get SDR, reading large records in chunks when the BMC cannot return them at once, and reserving the repository (Reserve SDR Repository) when the BMC requires it or cancels the reservation; the walk is done once per client and shared with frus() (SDR cache[2]);
  2. sends Get Sensor Reading for every selected Full Sensor and Compact Sensor record.

Event-Only records (sensors without a reading), the locator and association records, and the OEM records are part of the walk but are not returned. A record the library cannot decode is skipped and listed in skippedRecords(); the walk goes on (Supported Commands[3]).

The walk reads only the sensors of the BMC's SDR repository, through the BMC itself: sensors owned by satellite controllers that the BMC does not bridge, and the Device SDRs of other controllers, are not read (#84[4], #105[5]).

Selecting sensors

The selection is applied before the readings are requested, so that an unselected sensor costs no round trip:

// Only the temperature and fan sensors: one Get Sensor Reading per selected sensor
SensorList sensors = bmc.sensors().types(SensorType.Temperature, SensorType.Fan).execute();

// By name, case-insensitively: * matches any characters, ? one character
SensorList cpuTemperatures = bmc.sensors().names("CPU? Temp", "*DTS*").execute();

// With a deadline of its own
SensorList all = bmc.sensors().timeout(Duration.ofSeconds(30)).execute();

The Sensor object

Each Sensor[6] is immutable and holds:

Method Content
name() The sensor name of the SDR record (CPU1 Temp, PSU2 Present, …)
number() The sensor number
type() What it measures or monitors: SensorType[7] (Temperature, Voltage, Fan, PowerSupply, …)
entity(), entityInstance() The entity the sensor belongs to: its type (EntityId.Processor, EntityId.PowerSupply, …) and instance number
unit() The SensorUnit[8] of the reading and thresholds
reading() The converted reading of a threshold sensor (OptionalDouble), empty for a discrete sensor or when the reading is unavailable
rawReading() The reading byte as the BMC sent it, before conversion
lowerNonCritical() … upperNonRecoverable() The six thresholds, converted like the reading; empty when the record does not define them, so that a threshold of 0 is a threshold
status() SensorStatus[9]: OK, NON_CRITICAL, CRITICAL or NON_RECOVERABLE for a threshold sensor, against its thresholds; OK for a discrete sensor that answers; UNAVAILABLE when the reading is unavailable
states() The asserted states of a discrete sensor, in the wording of ipmiutil (of ipmitool for the few states ipmiutil does not name), each once
rawStates() The same, as ReadingType[10]s
problem() Why the sensor has no reading and no states: the BMC refused the reading (with its completion code), the reading is not valid yet, or scanning is disabled; empty otherwise
record(), readingData() The decoded record (FullSensorRecord[11] or CompactSensorRecord[12]) and the GetSensorReadingResponseData[13], for everything else

SensorList[14], the result of execute(), is an unmodifiable List<Sensor> that also gives the SDR records the walk skipped (skippedRecords()).

Readings

For a Full Sensor record, the reading is converted to the sensor's unit with the record's linear formula (M, B and the exponents of IPMI 2.0, section 36.3), linearization included:

for (Sensor sensor : bmc.sensors().execute()) {
	sensor.reading().ifPresent(value -> System.out.println(sensor.name() + " = " + value + " " + sensor.unit()
			+ " (upper critical: " + sensor.upperCritical() + ", " + sensor.status() + ")"));
}

Ambient Temp = 17.0 DegreesC (upper critical: OptionalDouble[39.0], OK)
System Power = 92.0 Watts (upper critical: OptionalDouble.empty, OK)
Fan 1 = 6600.0 Rpm (upper critical: OptionalDouble.empty, OK)
System 3.3V = 3.38 Volts (upper critical: OptionalDouble[3.56], OK)

reading() is empty when the BMC flags the reading it does not vouch for (unavailable, scanning disabled), when the record has no analog reading, or when it refused the reading: problem() says which.

Note

A Compact record that describes several shared sensors is reported as a single sensor (#100[15]).

States

Discrete sensors (presence, redundancy, power supply status, processor status, …) report a set of asserted states instead of a value. states() returns the asserted states that have a description in the wording of ipmiutil:

PSU Redundancy: [Fully Redundant]
PSU1 Present: [Presence detected]
CPU0_Status: [Presence detected]

The states of a threshold sensor are the thresholds its reading is at or beyond. For OEM sensors (event/reading types 0x70 to 0x7F), whose states the specification does not define, the single state is the raw value of the state bytes: 0xHHLL (0xLL when the BMC returns a single state byte). An OEM sensor with no state asserted reports no state, like any discrete sensor.

sensors sdr sensor data record sensor reading thresholds temperature voltage fan power states ipmi bmc rmcp+ sensors fru sdr sel system event log chassis serial over lan java hardware monitoring
Links:
  • [1] apidocs/org/metricshub/ipmi/client/SensorsRequest.html
  • [2] configuration.html#sdr-cache
  • [3] supported-commands.html#sdr-records
  • [4] https://github.com/metricshub/ipmi-java/issues/84
  • [5] https://github.com/metricshub/ipmi-java/issues/105
  • [6] apidocs/org/metricshub/ipmi/client/Sensor.html
  • [7] apidocs/org/metricshub/ipmi/core/coding/commands/sdr/record/SensorType.html
  • [8] apidocs/org/metricshub/ipmi/core/coding/commands/sdr/record/SensorUnit.html
  • [9] apidocs/org/metricshub/ipmi/client/SensorStatus.html
  • [10] apidocs/org/metricshub/ipmi/core/coding/commands/sdr/record/ReadingType.html
  • [11] apidocs/org/metricshub/ipmi/core/coding/commands/sdr/record/FullSensorRecord.html
  • [12] apidocs/org/metricshub/ipmi/core/coding/commands/sdr/record/CompactSensorRecord.html
  • [13] apidocs/org/metricshub/ipmi/core/coding/commands/sdr/GetSensorReadingResponseData.html
  • [14] apidocs/org/metricshub/ipmi/client/SensorList.html
  • [15] https://github.com/metricshub/ipmi-java/issues/100
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