Move Inventory.Item.Board from Redfish Chassis to Redfish Assembly

[Gunnar Mills]

On 4/28/2021 1:44 PM, Ed Tanous wrote:
>>> On Wed, Apr 28, 2021 at 9:18 AM Gunnar Mills <gmills at linux.vnet.ibm.com> wrote:
>>>>
>>>>    From some discussion on Discord a few weeks ago. A newer way of
>>>> thinking in Redfish is for a simple rack server to just have one Redfish
>>>> Chassis and things like boards modeled as Redfish Assemblies under the
>>>> Chassis. Today we look for inventory item chassis and inventory
>>>> item board to populate the Chassis collection. I propose we move
>>>> the "Inventory.Item.Board" from Redfish Chassis to Redfish Assembly.
>>>
> 
> Here's an example of something that's type Board that creates sensors.
> https://github.com/openbmc/entity-manager/blob/master/configurations/A2UL16RISER.json
> There are several more like this.

 From follow-on discussion in Discord this afternoon.
Today the sensors to board association (e.g. the riser card above with 
sensors) is "chassis"/"all_sensor. It should be  "inventory"/"sensors" 
(Association Type #2: Linking a low-level hardware item to its sensors 
[a]). Redfish has a "RelatedItem" property on the Sensor schema. To 
populate the "RelatedItem" property we will use Association Type #2. 
This is the first step to moving Inventory.Item.Board to a Redfish 
Assembly, this is to ensure no relationships are lost.

[a]https://github.com/openbmc/docs/blob/919a7b6816a5f16aa72d298e81e0756d95d5031e/architecture/sensor-architecture.md#association-type-2-linking-a-low-level-hardware-item-to-its-sensors

> 
> I don't mean to throw up roadblocks, and I definitely don't know what
> the solution is here, but we'll need to solve it before something like
> this can go through.
> 
We further discussed how staging this change might work, it probably 
involves a compile flag for some time and separately adding 
Inventory.Item.Board to Assembly and later removing from Chassis.

Gunnar