[collector] Use NetworkPolicy for communication between Jaeger and database pods.

[Ankit152]

Component(s)

collector

Is your feature request related to a problem? Please describe.

With the in-memory storage solution for Jaeger being in place (extension service and ingress), it's also crucial to add support for storing traces in the databases supported by Jaeger binary in a Kubernetes cluster.
The challenge here is to ensure effective and reliable communication between Jaeger and database, where traces will be stored and will be fetched whenever required.

Describe the solution you'd like

In a case where communication is crucial between two pods, NetworkPolicy will turn out to be fruitful.
User or Cluster Admin can create a database deployment on their own and that configuration can be used in the OpenTelemetery Operator spec to create a Jaeger instance. This will also give users flexibility of maintaining and managing the database by creating multiple replicas ruling out single-point-of-failure.
The idea is to add support in OpenTelemetry operator for creating NetworkPolicy when the user performs kubectl apply, automating the entire flow.

Describe alternatives you've considered

No response

Additional context

The whole idea is presented over here.
Jaeger V2: jaegertracing/jaeger-operator#2717

[Ankit152]

The implementation details can be discussed in the public so that we all can agree on things.
cc @yurishkuro @pavolloffay @iblancasa @jkowall

[pavolloffay]

I don't see a justification for using a network policy. The backed can be reached by a normal k8s service.

Users could optionaly configure network policy to enforce security, however this can be done outside of the operator.

[Ankit152]

Alright, that makes sense. Since we need a service to establish connection, are we expecting that as a part of the operator or it would be outside the operator?