1# Redfish OEM Resources 2 3The Redfish specification allows for OEM resources and properties to be 4implemented by OEMs. As a general rule, OpenBMC discourages the use of OEM 5namespaces in APIs. In line with this, bmcweb does not expose an API for adding 6OEM properties in a backward API compatible way for resources that have not been 7merged to master. 8 9## Why? 10 11OEM properties in an open source project pose many problems when compared to 12their closed source brethren in terms of reliability, code reuse, compatibility, 13and maintenance. 14 151. As a general rule, OpenBMCs external Redfish API aims to be as compatible 16 between systems as possible. Adding machine-specific resources, properties, 17 and types largely defeats some of that goal, as clients must implement 18 machine-specific APIs, some of which are likely to overlap, which increases 19 the amount of code overall. OpenBMC also has very little visibility into 20 clients that might interface with Redfish, and therefore needs to take care 21 when adding new, non-standard APIs. 22 232. In practice, OEM resources trend toward a lower level of quality and testing 24 than their spec-driven alternatives, given the lack of available systems to 25 test on, and the limited audience of both producers and consumers. This poses 26 a problem for maintenance in the long run, as it is very difficult to make a 27 breaking change to an external API, given that clients are likely to be 28 implemented in projects that OpenBMC isn't aware of. 29 303. If a given workflow eventually becomes standardized, OpenBMC OEM endpoints 31 now have to break an API boundary to be able to move to the standard 32 implementation. Given the amount of effort it takes to break an API, it is 33 much simpler to wait for the standard to be completed before merging the OEM 34 code to master. 35 364. DMTF has many more Redfish experts than OpenBMC. While the bmcweb maintainers 37 do their best to stay current on the evolving Redfish ecosystem, we have 38 significantly limited scope, knowledge, and influence over the standard when 39 compared to the experts within DMTF. Getting a DMTF opinion almost always 40 leads to positive API design changes up front, which increases the usefulness 41 of the code we write within the industry. 42 43## How? 44 45If you've read the above, and still think an OEM property is warranted, please 46take the following steps. 47 481. Present the new feature and use case to DMTF either through the 49 [Redfish forum](https://www.redfishforum.com), or at a DMTF meeting. If 50 possible, message the new feature through the normal openbmc communications 51 channels to ensure OpenBMC is properly represented in the meeting/forum. 522. If DMTF is interested in the proposal, proceed using their documented process 53 for change requests, and get your schema changes standardized; While OpenBMC 54 does not merge new schemas that have not been ratified by DMTF, feel free to 55 push them to gerrit. If the features are major enough to warrant it, feel 56 free to discuss with maintainers about hosting a branch within gerrit while 57 your DMTF proposal is in progress. If the DMTF feedback is documented as 58 something to the effect of "this use case is unique to OpenBMC", proceed to 59 write an OpenBMC design document about the new feature you intend to 60 implement as OEM, under the OpenBMC (generic to all platforms) OEM namespace. 613. If OpenBMC feedback is that this feature is specific to a single OEM or ODM, 62 and is unlikely to be used across platforms, then maintainers will provide 63 you the option of adding your feature under an OEM/ODM specific namespace. 64 65Regardless of the OEM namespace being used, implementations should plan to 66implement all appropriate CSDL and OpenAPI schemas for their given OEM 67resources, should pass the redfish service validator, and should follow redfish 68API design practices. We require this same level of quality as non OEM to ensure 69that OEM is truly required by the contributor to satisfy their use case. If OEM 70were held to a lesser level of quality requirements, bwcweb would consist 71entirely of OEM code. 72 73bmcweb maintainers retain the final approval on OEM schemas. 74