# OpenTelemetry Metrics Format

The OpenTelemetry receiver supports ingesting agent metrics by meter-system. The OAP can load the configuration at bootstrap.
If the new configuration is not well-formed, the OAP may fail to start up. The files are located at `$CLASSPATH/otel-rules`.

Supported handlers:

* `otlp`: [OpenTelemetry](https://github.com/open-telemetry/opentelemetry-collector/tree/1c217b366fbdb209044d8f4c3fece079ae23bd3b/exporter/otlpexporter) gRPC service handler.

**Notice:**  Set `SW_OTEL_RECEIVER=default` through system environment or change `receiver-otel/selector=${SW_OTEL_RECEIVER:default}` to activate the OpenTelemetry receiver.

The rule file should be in YAML format, defined by the scheme described in [MAL](../../concepts-and-designs/mal.md).
Note: `receiver-otel` only supports the `group`, `defaultMetricLevel`, and `metricsRules` nodes of the scheme due to its push mode.

To activate the `otlp` handler and relevant rules of `istio`:

```yaml
receiver-otel:
  selector: ${SW_OTEL_RECEIVER:default}
  default:
    enabledHandlers: ${SW_OTEL_RECEIVER_ENABLED_HANDLERS:"otlp-metrics"}
    enabledOtelMetricsRules: ${SW_OTEL_RECEIVER_ENABLED_OTEL_METRICS_RULES:"istio-controlplane"}
```

The receiver adds label with key `node_identifier_host_name` to the collected data samples,
and its value is from `net.host.name` (or `host.name` for some OTLP versions) resource attributes defined in OpenTelemetry proto,
for identification of the metric data.

**Notice:** In the resource scope, dots (.) in the attributes' key names are converted to underscores (_), whereas in the metrics scope, they are not converted.

| Description                             | Configuration File                                  | Data Source                                                                                                           |
|-----------------------------------------|-----------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------|
| Metrics of Istio Control Plane          | otel-rules/istio-controlplane.yaml                  | Istio Control Plane -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                             |
| Metrics of SkyWalking OAP server itself | otel-rules/oap.yaml                                 | SkyWalking OAP Server(SelfObservability) -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server        |
| Metrics of Linux OS                     | otel-rules/vm.yaml                                  | prometheus/node_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                        |
| Metrics of Windows OS                   | otel-rules/windows.yaml                             | prometheus-community/windows_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server           |
| Metrics of K8s cluster                  | otel-rules/k8s/k8s-cluster.yaml                     | K8s kube-state-metrics -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                          |
| Metrics of K8s cluster                  | otel-rules/k8s/k8s-node.yaml                        | cAdvisor & K8s kube-state-metrics -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server               |
| Metrics of K8s cluster                  | otel-rules/k8s/k8s-service.yaml                     | cAdvisor & K8s kube-state-metrics -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server               |
| Metrics of MYSQL                        | otel-rules/mysql/mysql-instance.yaml                | prometheus/mysqld_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                      |
| Metrics of MYSQL                        | otel-rules/mysql/mysql-service.yaml                 | prometheus/mysqld_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                      |
| Metrics of PostgreSQL                   | otel-rules/postgresql/postgresql-instance.yaml      | prometheus-community/postgres_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server          |
| Metrics of PostgreSQL                   | otel-rules/postgresql/postgresql-service.yaml       | prometheus-community/postgres_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server          |
| Metrics of Apache APISIX                | otel-rules/apisix.yaml                              | apisix prometheus plugin -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                        |
| Metrics of AWS Cloud EKS                | otel-rules/aws-eks/eks-cluster.yaml                 | AWS Container Insights Receiver -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                 |
| Metrics of AWS Cloud EKS                | otel-rules/aws-eks/eks-service.yaml                 | AWS Container Insights Receiver -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                 |
| Metrics of AWS Cloud EKS                | otel-rules/aws-eks/eks-node.yaml                    | AWS Container Insights Receiver -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                 |
| Metrics of Elasticsearch                | otel-rules/elasticsearch/elasticsearch-cluster.yaml | prometheus-community/elasticsearch_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server     |
| Metrics of Elasticsearch                | otel-rules/elasticsearch/elasticsearch-index.yaml   | prometheus-community/elasticsearch_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server     |
| Metrics of Elasticsearch                | otel-rules/elasticsearch/elasticsearch-node.yaml    | prometheus-community/elasticsearch_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server     |
| Metrics of Redis                        | otel-rules/redis/redis-service.yaml                 | oliver006/redis_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                        |
| Metrics of Redis                        | otel-rules/redis/redis-instance.yaml                | oliver006/redis_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                        |
| Metrics of RabbitMQ                     | otel-rules/rabbitmq/rabbitmq-cluster.yaml           | rabbitmq-prometheus -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                             |
| Metrics of RabbitMQ                     | otel-rules/rabbitmq/rabbitmq-node.yaml              | rabbitmq-prometheus -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                             |
| Metrics of MongoDB                      | otel-rules/mongodb/mongodb-cluster.yaml             | percona/mongodb_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                        |
| Metrics of MongoDB                      | otel-rules/mongodb/mongodb-node.yaml                | percona/mongodb_exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                        |
| Metrics of Kafka                        | otel-rules/kafka/kafka-cluster.yaml                 | prometheus/jmx_exporter/jmx_prometheus_javaagent -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server |
| Metrics of Kafka                        | otel-rules/kafka/kafka-broker.yaml                  | prometheus/jmx_exporter/jmx_prometheus_javaagent -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server |
| Metrics of ClickHouse                   | otel-rules/clickhouse/clickhouse-instance.yaml      | ClickHouse(embedded prometheus endpoint) -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server        |
| Metrics of ClickHouse                   | otel-rules/clickhouse/clickhouse-service.yaml       | ClickHouse(embedded prometheus endpoint) -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server        |
| Metrics of RocketMQ                     | otel-rules/rocketmq/rocketmq-cluster.yaml           | rocketmq-exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                                 |
| Metrics of RocketMQ                     | otel-rules/rocketmq/rocketmq-broker.yaml            | rocketmq-exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                                 |
| Metrics of RocketMQ                     | otel-rules/rocketmq/rocketmq-topic.yaml             | rocketmq-exporter -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                                 |
| Metrics of Flink                        | otel-rules/flink/flink-jobManager.yaml              | flink jobManager -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                                 |
| Metrics of Flink                        | otel-rules/flink/flink-taskManager.yaml             | flink taskManager -> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server                                |
| Metrics of Flink                        | otel-rules/flink/flink-job.yaml                     | flink jobManager &  flink taskManager-> OpenTelemetry Collector -- OTLP exporter --> SkyWalking OAP Server             |