Metrics Generator needs blob storage config?

Grafana Tempo
1

I’m currently using Azure Blob Storage as a backend for Tempo, as well as the Bitnami chart for Tempo. When I pass -config.expand-env=true for all 5 components as per the official configuration, all of the components seem to run fine, except for the metrics-generator pod, which keeps on crash loop back offing.

It crashes with this error message:

│ level=error ts=2025-02-12T00:29:55.338979444Z caller=main.go:124 msg="error running Tempo" err="failed to init module services: error initialising module: optional-store: failed to create store:  │
│ getting storage container: decode account key: illegal base64 data at input byte 0"                                                                                                                 │

When I pass the flag “-config.expand-env=true” and the secret, it seems to be healthy again. My question is–why? As far as I can tell by reading through the metrics-generator configuration, blob storage is not needed at any point. So why would the metrics-generator fail to run without the additional flag?

This is the configuration for the backend:

      storage:
        trace:
          backend: azure
          azure:
            container_name: tempo
            storage_account_name: storage01
            storage_account_key: ${STORAGE_ACCOUNT_ACCESS_KEY}
          wal:
            path: {{ .Values.tempo.dataDir }}/wal