ADR for exposing MCAD observability metrics

PCF-ADR-0008-mcad-observ-metrics.md

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+# Project CodeFlare - MCAD Custom Metrics Emission
+
+
+|                |                                                                                   |
+| -------------- | --------------------------------------------------------------------------------- |
+| Date           | 10/03/2023                                                                        |
+| Scope          |                                                                                   |
+| Status         | implementable                                                                     |
+| Authors        | [Ronen Schaffer](@ronensc), [Rachel Brill](@rachelt44), [Eran Raichstein](@eranra)|
+| Supersedes     | N/A                                                                               |
+| Superseded by: | N/A                                                                               |
+| Issues         |                                                                                   |
+| Other docs:    | none                                                                              |
+
+## What
+
+Emit MCAD custom metrics such as total allocatable CPU, GPU and memory.
+
+## Why
+
+MCAD custom metrics information is important for enabling generation of an overall up-to-date observablity view of the running app wrappers and connecting to other stack layers.
+This will align MCAD with other existing components in OCP that expose metrics in Prometheus format and allow the collection and building of cross-component context.
+
+## Goals
+
+* Emit MCAD custom metrics 
+
+## Non-Goals
+
+The following are not included in this ADR:
+* Emit metrics of other components
+* Connect MCAD metrics to metrics of other components
+
+## How
+
+Register collected metrics with the runtime controller of the CodeFlare Operator. The metrics will be exposed in standard Prometheus format.
+
+
+## Alternatives
+
+Given the CodeFlare operator re-design that enables off-the-shelf exposure of metrics, we have not currently considered any alternatives.
+Currently, the MCAD dashboard relies on external components to report the information and there is no guaranty that what MCAD is using aligns to that information.
+
+
+## Stakeholder Impacts
+
+| Group                  | Key Contacts                          | Date | Impacted? |
+| ---------------------- | --------------------------------------| ---- | --------- |
+| CodeFlare Operator     | Anish Asthana, Antonin Stefanutti     |      | yes       |
+| CodeFlare SDK          | Mustafa Eyceoz, Dimitri Saridakis     |      | no        |
+| Dashboard              | Mohammed Abdi                         |      | yes       |
+| MCAD                   | Abhishek Malvankar, Antonin Stefanutti|      | yes       |
+
+
+## References
+
+
+
+## Reviews
+
+Reviews on the pull request will suffice for the approval process. At least 2 approvals are required prior to this ADR being merged. The ADR must also remain open for at least one week.