How to Opentelemetry metrics are get in OpenSearch dashboard?

[Ommkwn2001]

Describe the bug

I install OpenSearch Dashboard , Dataprepper and Opentelemetry use with Helm chart.

So i First of i install OpenSearch and OpenSearch Dashboard and for the automatic generate index in the Opensearch dashboard i install the "Dataprepper" with this configuration in value.yaml code.

Dataprepper configuration code in value.yaml:

`

  config:
    otel-metrics-pipeline:
      workers: 8
      delay: 3000
      source:
        otel_metrics_source:
          health_check_service: true
          ssl: false
      processor:
        - otel_metrics:
            calculate_histogram_buckets: true
            calculate_exponential_histogram_buckets: true
            exponential_histogram_max_allowed_scale: 10
            flatten_attributes: false
      sink:
        - opensearch:
            hosts: ["https://opensearch-cluster-master.default.svc.cluster.local:9200"]
            username: "admin"
            password: "TadhakDev01"
            insecure: true
            index_type: custom
            index: ss4o_metrics-otel-%{yyyy.MM.dd}
            bulk_size: 4`

there are automatic create an index in the Opensearch dashboard with this name "ss4o_metrics-otel-%{yyyy.MM.dd}".

and i install Opentelemetry with this configuration in value.yaml code.

Opentelemetry configuration code in value.yaml:

`

 config:
    exporters:
      otlp/data-prepper:
        endpoint: my-data-prepper-release.default.svc.cluster.local:21891
        tls:
          insecure: true
  
      debug: {}
    extensions:
      # The health_check extension is mandatory for this chart.
      # Without the health_check extension the collector will fail the readiness and liveliness probes.
      # The health_check extension can be modified, but should never be removed.
      health_check:
        endpoint: ${env:MY_POD_IP}:13133
    processors:
      batch: {}
      # Default memory limiter configuration for the collector based on k8s resource limits.
      memory_limiter:
        check_interval: 5s
        limit_mib: 512 
        spike_limit_percentage: 25
    receivers:
      kubeletstats:
        insecure_skip_verify: true
        # collection_interval: 30s
        metrics:
          container.cpu.time:
            enabled: true
          container.cpu.utilization:
            enabled: true
          container.memory.available:
            enabled: true
          container.memory.usage:
            enabled: true
          k8s.node.cpu.time:
            enabled: true
          k8s.node.cpu.usage:
            enabled: true
          k8s.node.memory.available:
            enabled: true
          k8s.node.memory.usage:
            enabled: true
          k8s.pod.cpu.time:
            enabled: true
          k8s.pod.cpu.usage:
            enabled: true
          k8s.pod.memory.available:
            enabled: true
          k8s.pod.memory.usage:
            enabled: true
          
      k8s_cluster:
        node_conditions_to_report: [Ready, MemoryPressure]
        allocatable_types_to_report: [cpu, memory]
        metrics:
          k8s.container.cpu_limit:
            enabled: true
          k8s.container.cpu_request:
            enabled: true
          k8s.container.memory_limit:
            enabled: true
          k8s.container.memory_request:
            enabled: true
      zipkin:
        endpoint: ${env:MY_POD_IP}:9411
    service:
      telemetry:
        metrics:
          address: ${env:MY_POD_IP}:8888
      extensions:
        - health_check
      pipelines:
        logs:
          exporters:
            - debug
          processors:
            - memory_limiter
            - batch
          receivers:
            - otlp
        metrics:
          receivers: [hostmetrics]
          processors: []
          exporters: [otlp/data-prepper]`

when i install this Opentelemetry than my index "ss4o_metrics-otel-%{yyyy.MM.dd}" total size are automatically high.
this is the index image:

there are all metrics are show in the "Discover" in OpenSearch dashboard.
this is the "Discover" image :

but in the OpenSearch dashboard "Metrics" there are not any metrics are available in this "Metrics" form
this is the "Metrics" image :

Expected behavior
So i want to all index metrics are get in the OpenSearch dashboard "Metrics".

OpenSearch Version
Please list the version of OpenSearch being used.

Dashboards Version
OpenSearch Dashboards version : 2.16.0

Host/Environment (please complete the following information):

• Browser : Firefox

[LDrago27]

@opensearch-project/admin move it to observability-dashboards

[andrross]

[Catch All Triage - 1, 2, 3]

[glelarge]

Hi, I met the same issue, index is displayed in the select box, but no metrics displayed.

Cause

Checking the developer console reveals a 500 HTTP request with this message:

Fetch Document Names Error:Error: Fetch Otel Metrics Error:[illegal_argument_exception] Text fields are not optimised for operations that require per-document field data like aggregations and sorting, so these operations are disabled by default. Please use a keyword field instead. Alternatively, set fielddata=true on [name] in order to load field data by uninverting the inverted index. Note that this can use significant memory.

Temp fix

Following this post the mapping API helped to change the type of the name field to the correct type keyword, and now the metrics appears correctly :

Expected behavior

The mapping field type of name should be set to keyword.

I didn't find exactly what provides the default mapping used to create the index, and what actually creates this mapping on the index: dataprepper, dashoard or plugin...
Another curious thing is the mapping creation flow:

• if OSD is started without nothing sending metrics, the index mapping is not created
• the mapping seems to be created at metrics reception

So I'm asking if mapping rely only on the provided template or also on received data.

Permanent workaround

To fix this error permanently, we have configured the data prepper deployment with a custom mapping downloaded directly from the OpenSearch catalog :
https://github.com/opensearch-project/opensearch-catalog/blob/main/schema/observability/metrics/metrics-1.0.0.mapping

I attached the yaml configuration for the data prepper metrics pipeline.

Next

That's not finished, only HISTOGRAM metrics are displayed, I don't know why, so I created this #2236