[tempo] helm chart is not ready for monolithic scaling

[Daniel Strobusch]

I am currently attempting to run Grafana Tempo in monolithic mode with scaling, following the instructions provided in the Scaling monolithic mode documentation.

However, it seems that the helm chart is not well-prepared for this scenario or lacks sufficient documentation.

According to the Scaling monolithic mode guide, the -target parameter needs to be set to scalable-single-binary. This can be achieved by adding the following to the values in the YAML file:

    extraArgs:
      target: scalable-single-binary

Unfortunately, the pods fail to start up and display the following error message:

level=error ts=2024-04-22T08:32:45.730366914Z caller=main.go:121 msg="error running Tempo" err="failed to init module services: error initialising module: querier: frontend worker address not specified"

Additionally, it appears that a headless service is required to configure the memberlist.join_members property, as mentioned in the memberlist configuration documentation. However, the headless service is either missing from the helm chart or there is a misconfiguration, as indicated in issue #3042.

It would be greatly appreciated if the helm chart could support scalable-single-binary or if the readme could include a statement clarifying that only singleton deployments are currently supported.