ipmi sensor naming in ceilometer is not consumer friendly
I've found the IPMI ceilometer sensor naming structure difficult to deal with from a programmatic perspective if a consumer wants to simply read all the sensors for a given Ironic Node. The IPMI sensor implementation names the ceilometer meters generically as "hardware.ipm.sensortype" and the resource ID in ceilometer is a concatenation of Ironic Node UUID followed by a dash and a ceilometer capable transformation of the ipmitool reported "Sensor ID". With this structure, there is no simple ceilometer API available to return all the sensors within a platform. The only way I could think of to find all the sensors for a given Ironic Node UUID is to query ceilometer for every resource and then hand match the resource ID text string with the Ironic Node UUID. If there are a lot of platforms, the number of Resource IDs will be very large and the returned resource ID list could easily be huge. Another interesting thing to ponder is what happens when you attempt to list all the samples for the meter named say "hardware.ipmi.temperature". Listing all the samples for "hardware.ipmi.temperature" will attempt to return you every sensor sample for every temperature sensor ever captured since the beginning of time.
Here is an example output from ceilometer meter-list with the current IPMI sensor naming scheme.
| Name | Type | Unit | Resource ID
| hardware.ipmi.current | gauge | W | edafe6f4-5996-4df8-bc84-7d92439e15c0-power_meter_(0x16)
| hardware.ipmi.temperature | gauge | C | edafe6f4-5996-4df8-bc84-7d92439e15c0-16-system_board_(0x15)
I believe a better approach would be to name each ceilometer meter uniquely within a platform and assign each meter a Resource ID equal to the Ironic Node UUID that the meter is associated with. This naming would enable the consumer to query ceilometer for a specific Resource ID which matches the Ironic Node UUID. This query would result in ceilometer returning a single resource containing direct links to all the sensors associated with the resource. Here is an example of a different ceilometer naming scheme which enables ceilometer querying for a specific Ironic Nodes platform information.
| Name | Type | Unit | Resource ID
| hardware.ipmi.current: power_meter_(0x16) | gauge | W | edafe6f4-5996-4df8-bc84-7d92439e15c0
| hardware.ipmi.current:16-system_board_(0x15) | gauge | W | edafe6f4-5996-4df8-bc84-7d92439e15c0
There was quite a lot of discussion about this when it was created, so I think if we dredge up the respective reviews we should be able to find the rationale and either all will become clear or we can fix it. I can't look now, but will if no one else has gotten around to it by early next week.