Service/service_name is coming as unknown_service

Grafana Loki
1

Hi, we are facing srevice/service_name = unknown_service issue, Plugin used is fluent-plugin-grafana-loki. We tried below config in Loki chart and the other config on fluentd side, please check and advise:

Loki-chart-config:

limits_config:
discover_service_name:
- index

Fluentd-side config:

        index $.index

        service_name $.index

        service $.index

      </label>

full fluentd loki-config:

  <label @REWRITTEN>

    <match \*\*>

      @type loki

      url "#{ENV\['LOKI_URL'\]}"

      ca_cert /secure/tls-certs/ca.crt

      line_format json

      

      \# FIX 1: Provide ONLY 'index' and 'valli'. 

      \# Remove 'service_name' and 'service' so Loki's chart can discover 'index' automatically.

      <label>

        valli $.index

        index $.index

        service_name $.index

        service $.index

      </label>

      \# FIX 2: Do NOT include 'remove_keys index'. 

      \# If you remove it here, Fluentd's buffer chunking breaks during evaluation.

      \# FIX 3: Keep $.index as the primary memory chunk routing key.

      <buffer $.index>

        @type memory

        flush_interval 1s

        retry_type periodic

        retry_forever false

        retry_wait 10s

        retry_max_times 2

        chunk_limit_size 8m

        total_limit_size 256MB

        overflow_action drop_oldest_chunk

        flush_thread_count 16

        queued_chunks_limit_size 32

        flush_at_shutdown true

      </buffer>

    </match>

  </label>
2

If you are using fluentd, pretty sure you beed one label block per label. For example:

<label>
  valli $.index
</label>

<label>
  index $.index
</label>

<label>
  service_name $.index
</label>

<label>
  service $.index
</label>