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

[Ed Tanous]

On Wed, Apr 28, 2021 at 12:38 PM Gunnar Mills <gmills at linux.vnet.ibm.com> wrote:
>
> On 4/28/2021 10:46 AM, 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.[1][2] Today we look for inventory item chassis and inventory
> >> item board[3] to populate the Chassis collection.[4] I propose we move
> >> the "Inventory.Item.Board" from Redfish Chassis to Redfish Assembly.
> >> Does this break anyone?
> >
> > This will definitely break people, given that sensors can be attached
> > to boards today, and (unless I'm mistaken) Assemblies don't have their
> > own sensors.  Is there a solution to the sensor issue baked into this
> > proposal?
>
> Looking at the documentation on the sensor associations[1],
> the bmcweb code, and association code[2] (e.g. [3]) sensors all look to
> be associated with an inventory item chassis today for Redfish Chassis
> <-> sensors. If there are sensors associated to boards with the
> "chassis" association ("all_sensors" is the reverse association), they
> would need to be moved to an inventory item chassis. I don't see any
> though unless I missed something.

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.

The problem here is that they are in fact... a board.  They are not a
chassis under how we currently define the item interface, and moving
them to be a Chassis would cause them to report as ChassisType =
Rackmount in the Redfish Chassis schema, which is definitely
incorrect.

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.

>
> [1]https://github.com/openbmc/docs/blob/919a7b6816a5f16aa72d298e81e0756d95d5031e/architecture/sensor-architecture.md#association-type-1-linking-a-chassis-to-all-sensors-within-the-chassis
>
> [2]https://github.com/search?q=org%3Aopenbmc+all_sensors&type=code
>
> [3]https://github.com/openbmc/openbmc/blob/c3d88e4d9fcc08e1aae7cc9d0337c0261e996c64/meta-quanta/meta-gbs/recipes-phosphor/inventory/phosphor-inventory-manager/associations.json#L389