--tracing.config to replace environment variables

[carlosjgp]

Is your proposal related to a problem?

When using OpenTelemetry agents (Deamonset) to ingest traces and decorate them with the node and pod metadata
container envs

- name: HOST_IP
  valueFrom:
    fieldRef:
      apiVersion: v1
      fieldPath: status.hostIP

flag

    --tracing.config=type: JAEGER
    config:
      service_name: "thanos"
      agent_host: "${HOST_IP}"
      agent_port: 14250

Describe the solution you'd like

Something similar for the tracing.config flag
#4327

(Describe your proposed solution here.)

Describe alternatives you've considered

Use OTEL Deployment with a Service but I'll lose important metadata

Additional context

Related with #1972

[matej-g]

I think this is a valid request 👍 Help needed! Would you be interested in taking this @carlosjgp?

[saswatamcode]

I think we already have env substitution for --tracing.config flag as defined here. The env substitutions follows K8s style though so it would be something like this. :)

    --tracing.config=type: JAEGER
    config:
      service_name: "thanos"
      agent_host: "$(HOST_IP)"
      agent_port: 14250

[matej-g]

Awesome! So we actually have this already? Then we can close this issue unless @carlosjgp has further comments.

[matej-g]

Closing this as it truly seems this is already implemented, thanks @saswatamcode 👍