Requirement
1.0 | Supports Redfish version 1.0 |
|
2.0 | Support metrics from various type of sensors |
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3.0 | Supports filtering the sensor type |
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4.0 | out-band monitoring |
Overview
DMTF’s Redfish is a standard API designed to deliver simple and secure management for converged, hybrid IT and the Software Defined Data Center (SDDC). Both human readable and machine capable, Redfish leverages common Internet and web services standards to expose information directly to the modern tool chain. Delivering both in‐band and out‐of‐band manageability, Redfish continues to expand to address customer use cases and technology for a holistic data center management experience.
Why Redfish?
Until Redfish, interoperable management standards were lacking for modern data center environments. As organizations shift to scale‐ out solutions, legacy standards are insufficient to successfully manage numerous simple and multi‐node servers or hybrid infrastructures. Legacy solutions has problems related to security and HW dependencies, lacking the agnostic nature thats needed for the modern datacenter.
An open industry standard specification and schema, Redfish specifies a RESTful interface and utilizes defined JSON payloads ‐ usable by existing client applications and browser‐based GUI.
Why REST, HTTP and JSON?
Combining language support with the ubiquity of REST, HTTP and JSON, Redfish enables IT management tasks to be performed using the same skill set and tool chain as other IT and dev/ops tasks.RESTful protocols are rapidly replacing SOAP as the cloud ecosystem is adopting REST, and the web API community has followed suit. RESTful protocols are much quicker to learn than SOAP, and they have the simplicity of being a data pattern (as REST is not strictly a protocol) mapped to HTTP operations directly.
References :
https://www.dmtf.org/sites/default/files/2017_12_RedfishTechnicalOverview.pdf
https://www.dmtf.org/sites/default/files/2017_12_Redfish_Introduction_and_Overview.pdf
Design
Redfish plugin
The redfish plugin collects information about sensors provided by BMC:
Name | Type | Type Instance | Description | Comment |
- | Sensor type | Sensor name | Sensor types and sensor names are not defined and are generated for each sensor individually. | Depends to hardware. |
Plugin configuration
The following configuration options should be supported by redfish collectd plugin:
Name | Description |
Interval | The interval within which to retrieve information about sensors in seconds |
Sensor | Selects sensors to collect information. |
Username | BMC username |
Password | BMC password for the username in question |
Address | IP address of the REST API Endpoint for accessing the BMC |
Version | Redfish version |
Here is an example of the plugin configuration section of collectd.conf file for the python based plugin module:
<Plugin python>
Import "redfish_sensors_plugin"
<Module "redfish_sensors_plugin">
Username "<username>"
Password "<password>"
Interval <poll-interval-seconds>
sensor ["fan:power:thermal"]
Address "<ipaddress>"
Version "[v1]"
Verbose false
Debug false
</Module>
</Plugin>
Note : Plan is to move from python based plugin to C based plugin
Implementation details
To support the redfish based sensor monitoring, the standard redfish interfaces are used as mentioned in the DMTF. Idea is to use as much possible the standard REST API URLs to reach the sensor resources. In order to implement and utilize the redfish interfaces one must understand the concept of resoure maps in DMTF redfish architecture.
The resource traversing for each elements can happen via well defined resource map. As described in the below diagram, These resource maps can be used directly to depict the REST URL to use GET or POST requests to certain resources. For the purpose of this plugin, the main focus is on the resources below /"redfish/v1/Chassis/<id>".
Resource Map in Redfish (courtsey : DMTF)
Following redfish REST query outputs the current sensor status of Fan (for "Fan_SYS4_2" with member id 9) and its corresponding metadata. "ReadingRPM" parameters is the main value of concern here which shows the current Fanspeed.
[mansingh@euca- ~]$ curl -s https://192.168.0.10/redfish/v1/Chassis/1/Thermal/Fans/9 -k -u admin:admin | python -m json.tool
{
"@odata.context": "/redfish/v1/$metadata#Chassis/1/Thermal/Fans/Members/$entity",
"@odata.id": "/redfish/v1/Chassis/1/Thermal/Fans/9",
"@odata.type": "#Thermal.1.0.0.Thermal",
"Fans": {
"@odata.id": "/redfish/v1/Chassis/1/Thermal/Fans/9",
"FanName": "Fan_SYS4_2",
"LowerThresholdCritical": "500.000",
"LowerThresholdFatal": "0.000",
"LowerThresholdNonCritical": "1000.000",
"MaxReadingRange": "0xFF",
"MemberId": 9,
"MinReadingRange": "0x00",
"ReadingRPM": "12600.000",
"RelatedItem": [
{
"@odata.id": "/redfish/v1/Systems/1"
},
{
"@odata.id": "/redfish/v1/Chassis"
}
],
"RelatedItem@odata.count": 2,
"RelatedItem@odata.navigationLink": "/redfish/v1/Chassis/1/Thermal",
"SensorNumber": 201,
"Status": {
"State": "Enabled"
},
"UpperThresholdCritical": "0.000",
"UpperThresholdFatal": "0.000",
"UpperThresholdNonCritical": "0.000"
},
"Id": "Fans/$entity",
"Name": "Fans/$entity"
}
Following redfish REST query outputs the current sensor status of temperatures (for Temp_CPU0 with member id 1) and its corresponding metadata. "ReadingCelsius" parameters is the main value of concern here which shows the current temperature.
[mansingh@euca- ~]$ curl -s https://192.168.0.10/redfish/v1/Chassis/1/Thermal/temperatures/1 -k -u admin:admin | python -m json.tool
{
"@odata.context": "/redfish/v1/$metadata#Chassis/1/Thermal/Temperatures/Members/$entity",
"@odata.id": "/redfish/v1/Chassis/1/Thermal/Temperatures/1",
"@odata.type": "#Thermal.1.0.0.Thermal",
"Id": "Temperatures/$entity",
"Name": "Temperatures/$entity",
"Temperatures": {
"@odata.id": "/redfish/v1/Chassis/1/Thermal/Temperatures/1",
"LowerThresholdCritical": "0.000",
"LowerThresholdFatal": "0.000",
"LowerThresholdNonCritical": "0.000",
"MaxReadingRangeTemp": "0xFF",
"MemberId": 1,
"MinReadingRangeTemp": "0x00",
"Name": "Temp_CPU0",
"PhysicalContext": "",
"ReadingCelsius": "39.000",
"RelatedItem": [
{
"@odata.id": "/redfish/v1/Systems/1"
},
{
"@odata.id": "/redfish/v1/Chassis"
}
],
"RelatedItem@odata.count": 2,
"RelatedItem@odata.navigationLink": "/redfish/v1/Chassis/1/Thermal",
"SensorNumber": 170,
"Status": {
"State": "Enabled"
},
"UpperThresholdCritical": "100.000",
"UpperThresholdFatal": "0.000",
"UpperThresholdNonCritical": "99.000"
}
}
Following redfish REST query outputs the current sensor status of power (for "Volt_VR_DIMM_CD" with member id 11) and its corresponding metadata. "ReadingVolts" parameters is the main value of concern here which shows the current temperature.
[mansingh@euca- ~]$ curl -s https://192.168.0.10/redfish/v1/chassis/1/Power/voltages/11 -k -u admin:admin | python -m json.tool
{
"@odata.context": "/redfish/v1/$metadata#Chassis/1/Power/Voltages/Members/$entity",
"@odata.id": "/redfish/v1/Chassis/1/Power/Voltages/11",
"@odata.type": "#Power.1.0.0.Power",
"Id": "Voltage/$entity",
"Name": "Voltage/$entity",
"Voltages": {
"@odata.id": "/redfish/v1/Chassis/1/Power/Voltages/11",
"LowerThresholdCritical": "1.080",
"LowerThresholdFatal": "0.000",
"LowerThresholdNonCritical": "0.000",
"MaxReadingRange": "0xFF",
"MemberId": 11,
"MinReadingRange": "0x00",
"Name": "Volt_VR_DIMM_CD",
"PhysicalContext": "VoltageRegulator",
"ReadingVolts": "1.220",
"RelatedItem": [
{
"@odata.id": "/redfish/v1/Systems/1"
},
{
"@odata.id": "/redfish/v1/Chassis/1/Power"
}
],
"RelatedItem@odata.count": 2,
"RelatedItem@odata.navigationLink": "/redfish/v1/Chassis/1/Power",
"SensorNumber": 221,
"Status": {
"State": "Enabled"
},
"UpperThresholdCritical": "1.320",
"UpperThresholdFatal": "0.000",
"UpperThresholdNonCritical": "0.000"
}
}
Collectd'd standard framework calls are used to read the configurations details and then make a read callback for specified sensors. Once the sensor values are fetched, they are pushed to the cache. Following state diagram gives an idea on how the sensor values are picked.
Collectd redfish State diagram
List of supported sensors
The collectd redfish plugin implementation supports the following types of redfish sensors:
redfish Sensor type | CollectD sensor value type | Collected Sensor Units |
Power | voltage | Volts |
Temperature | temperature | Celsius |
Fan | fanspeed | RPM |
Considerations
Configuration Considerations
Deployment Considerations
If your platform does not support BMC – this plugin will be unloaded at initialization time.
API/GUI/CLI Considerations
Equivalence Considerations
Security Considerations
Alarms, events, statistics considerations
Not all metrics will be reported as not all types of sensors are supported by redfish plugin.
redfish plugin registers to listen for all type of sensor events received from System Event Log (SEL).
Redundancy Considerations
Performance Considerations
Testing Consideration
The timing interval requirement needs to be taken into consideration when conducting tests.
The Tests should be carried out on a system underload as well as a relatively idle system.
Other Considerations
Impact
The following table outlines possible impact(s) the deployment of this deliverable may have on the current system.
Ref | System Impact Description | Recommendation / Comments |
1 |
|
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Key Assumptions
The following assumptions apply to the scope specified in this document.
Ref | Assumption | Status |
1 |
|
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Key Exclusions
The following exclusions apply to the scope discussed in this document.
Ref | Exclusion | Status |
1 |
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Key Dependencies
The following table outlines the key dependencies associated with this deliverable.
Ref | Dependency | Status |
1 |
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