feat: add OTel resource attributes persistence per time series

Add end-to-end support for persisting OTel resource and scope attributes
from OTLP metrics ingestion through to query-time enrichment via info().

Key changes:
- Implement AppenderV2 in MimirAppender for OTLP resource context
- Store resource/scope attributes in TSDB head per-series
- Persist attributes to series_metadata.parquet on block flush
- Upload series_metadata.parquet to object storage
- Add distributed query path for resource attributes
- Wire store-gateway and ingester to /api/v1/resources endpoint
- Implement ResourceQuerier for info() PromQL function
- Port block builder to support resource attributes
- Use ReadSeriesMetadataFromReaderAt for content-addressed Parquet

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

Author: aknuds1

cmd/mimir/config-descriptor.json

@@ -6793,6 +6793,17 @@
           "fieldType": "boolean",
           "fieldCategory": "advanced"
         },
+        {
+          "kind": "field",
+          "name": "otel_persist_resource_attributes",
+          "required": false,
+          "desc": "Whether to persist OTel resource attributes per time series as metadata in Prometheus TSDB blocks. Resource attributes are stored in series_metadata.parquet files within blocks and can be queried via the /api/v1/resource_attributes endpoint.",
+          "fieldValue": null,
+          "fieldDefaultValue": false,
+          "fieldFlag": "distributor.otel-persist-resource-attributes",
+          "fieldType": "boolean",
+          "fieldCategory": "experimental"
+        },
         {
           "kind": "field",
           "name": "ingest_storage_read_consistency",

cmd/mimir/help-all.txt.tmpl

@@ -1315,6 +1315,8 @@ Usage of ./cmd/mimir/mimir:
     	Whether to enable automatic suffixes to names of metrics ingested through OTLP.
   -distributor.otel-native-delta-ingestion
     	[experimental] Whether to enable native ingestion of delta OTLP metrics, which will store the raw delta sample values without conversion. If disabled, delta metrics will be rejected. Delta support is in an early stage of development. The ingestion and querying process is likely to change over time.
+  -distributor.otel-persist-resource-attributes
+    	[experimental] Whether to persist OTel resource attributes per time series as metadata in Prometheus TSDB blocks. Resource attributes are stored in series_metadata.parquet files within blocks and can be queried via the /api/v1/resource_attributes endpoint.
   -distributor.otel-promote-resource-attributes comma-separated-list-of-strings
     	[experimental] Optionally specify OTel resource attributes to promote to labels.
   -distributor.otel-promote-scope-metadata

development/README.md

@@ -39,6 +39,18 @@ Available profiles:
 
 > **Note**: Compose down will stop all profiles unless specified.
 
+## OTLP Resource Attributes Demo
+
+The monolithic mode includes a demo script that showcases how Mimir persists OTel resource attributes from OTLP metrics. This demonstrates the end-to-end flow from OTLP ingestion through both ingesters and store-gateways.
+
+```bash
+cd mimir-monolithic-mode
+./compose-up.sh
+./scripts/otlp-resource-attrs-demo.sh
+```
+
+See [mimir-monolithic-mode/scripts/README.md](./mimir-monolithic-mode/scripts/README.md) for details.
+
 ## OTEL collector
 
 Experimental support for running OpenTelemetry collector in the Monolithic mode.

development/mimir-ingest-storage/config/runtime.yaml

@@ -3,3 +3,6 @@ overrides:
   anonymous:
     labels_query_optimizer_enabled: true
     ruler_evaluation_consistency_max_delay: 1m
+    otel_persist_resource_attributes: true
+    # Enable experimental PromQL functions for the info() function demo.
+    enabled_promql_experimental_functions: all

development/mimir-ingest-storage/docker-compose.jsonnet

@@ -184,6 +184,7 @@ std.manifestYamlDoc({
       hostname: 'nginx',
       image: 'nginxinc/nginx-unprivileged:1.22-alpine',
       depends_on: [
+        'distributor-1',
         'ingester-zone-a-1',
         'alertmanager-1',
         'ruler-1',
@@ -193,7 +194,7 @@ std.manifestYamlDoc({
       ],
       environment: [
         'NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx',
-        'DISTRIBUTOR_HOST=ingester-zone-a-1:8080',
+        'DISTRIBUTOR_HOST=distributor-1:8080',
         'ALERT_MANAGER_HOST=alertmanager-1:8080',
         'RULER_HOST=ruler-1:8080',
         'QUERY_FRONTEND_HOST=query-frontend:8080',

development/mimir-ingest-storage/docker-compose.yml

@@ -291,6 +291,7 @@
       - ".data-minio:/data:delegated"
   "nginx":
     "depends_on":
+      - "distributor-1"
       - "ingester-zone-a-1"
       - "alertmanager-1"
       - "ruler-1"
@@ -299,7 +300,7 @@
       - "grafana"
     "environment":
       - "NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx"
-      - "DISTRIBUTOR_HOST=ingester-zone-a-1:8080"
+      - "DISTRIBUTOR_HOST=distributor-1:8080"
       - "ALERT_MANAGER_HOST=alertmanager-1:8080"
       - "RULER_HOST=ruler-1:8080"
       - "QUERY_FRONTEND_HOST=query-frontend:8080"