Support prefix for OTEL environment variables in the Instrumentation CR

[pavolloffay]

The Quarkus runtime is already instrumented with OpenTelemtry, however it overrides OpenTelemtry env variables by adding QUARKUS_ prefix. Therefore the Quarkus app cannot be instrumented with the Instrumentation CR via instrumentation.opentelemetry.io/inject-sdk: "true".

https://quarkus.io/guides/opentelemetry#quarkus-opentelemetry_configuration

[pavolloffay]

The proposal of this ticket is to add prefix configuration for the env variables added by the operator.

[brunobat]

That would be great. Thanks @pavolloffay

[yuriolisa]

Can I take this one?

[TylerHelmuth]

@pavolloffay instead of adding a new env prefix, could we remove the constraint?

[jaronoff97]

Closed by #2768

[CaffeineDaemon]

I still struggle with using instrumentation.opentelemetry.io/inject-sdk: "true" with a quarkus app.
Sure, with the validation removed i can set all the OTEL environment variables myself with the QUARKUS_ prefix. But i am using the Instrumentation CR so i don't have to set all OTEL environment variables myself in the first place. I also can't use expansion to reference a variable like OTEL_PROPAGATORS like so:

spec:
  env:
  - name: QUARKUS_OTEL_EXPORTER_OTLP_ENDPOINT
    value: $(QUARKUS_OTEL_EXPORTER_OTLP_ENDPOINT)
  - name: QUARKUS_OTEL_PROPAGATORS
    value: $(OTEL_PROPAGATORS)

The variables are not expanded. Am i doing something wrong?

[jaronoff97]

@CaffeineDaemon it may be best to open a new issue and we can debug from there if you don't mind :)