Epic Goal

When users configure CMO to interact with systems outside of an OpenShift cluster, we want to provide an easy way to add the cluster ID to the data send.

Why is this important?

Technically this can be achieved today, by adding an identifying label to the remote_write configuration for a given cluster. The operator adding the remote_write integration needs to take care that the label is unique over the managed fleet of clusters. This however adds management complexity. Any given cluster already has a pseudo-unique datum, that can be used for this purpose.

• Starting in 4.9 we support the Prometheus remote_write feature to send metric data to a storage integration outside of the cluster similar to our own Telemetry service.
• In Telemetry we already use the cluster ID to distinguish the various clusters.
• For users of remote_write this could add an easy way to add such distinguishing information.

Scenarios

1. An organisation with multiple OpenShift clusters want to store their metric data centralized in a dedicated system and use remote_write in all their clusters to send this data. When querying their centralized storage, metadata (here a label) is needed to separate the data of the various clusters.
2. Service providers who manage multiple clusters for multiple customers via a centralized storage system need distinguishing metadata too. See https://issues.redhat.com/browse/OSD-6573 for example

Acceptance Criteria

• CI - MUST be running successfully with tests automated
• Release Technical Enablement - Provide necessary release enablement details and documents.
• Document how to use this feature

Dependencies (internal and external)

1. none

Previous Work (Optional):

1. none

Open questions::

Done Checklist

• CI - CI is running, tests are automated and merged.
• Release Enablement <link to Feature Enablement Presentation>
• DEV - Upstream code and tests merged: <link to meaningful PR or GitHub Issue>
• DEV - Upstream documentation merged: <link to meaningful PR or GitHub Issue>
• DEV - Downstream build attached to advisory: <link to errata>
• QE - Test plans in Polarion: <link or reference to Polarion>
• QE - Automated tests merged: <link or reference to automated tests>
• DOC - Downstream documentation merged: <link to meaningful PR>

Implementation proposal:

Expose a flag in the CMO configuration, that is false by default (keeps backward compatibility) and when set to true will add the _id label to a remote_write configuration. More specifically it will be added to the top of a remote_write relabel_config list via the replace action. This will add the label as expect, but additionally a user could alter this label in a later relabel config to suit any specific requirements (say rename the label or add additional information to the value).
The location of this flag is the remote_write Spec, so this can be set for individual remote_write configurations.