skywalking-java/docs/en/setup/backend/backend-health-check.md

Health Check

Health check intends to provide a unique approach to check the healthy status of OAP server. It includes the health status of modules, GraphQL and gRPC services readiness.

Health Checker Module.

Health Checker module could solute how to observe the health status of modules. We can active it by below:

health-checker:
  selector: ${SW_HEALTH_CHECKER:default}
  default:
    checkIntervalSeconds: ${SW_HEALTH_CHECKER_INTERVAL_SECONDS:5}

Notice, we should enable telemetry module at the same time. That means the provider should not be - and none.

After that, we can query OAP server health status by querying GraphQL:

query{
  checkHealth{
    score
    details
  }
}

If the OAP server is healthy, the response should be

{
  "data": {
    "checkHealth": {
      "score": 0,
      "details": ""
    }
  }
}

Once some modules are unhealthy, for instance, storage H2 is down. The result might be like below:

{
  "data": {
    "checkHealth": {
      "score": 1,
      "details": "storage_h2,"
    }
  }
}

You could refer to checkHealth query for more details.

The readiness of GraphQL and gRPC

We could opt to above query to check the readiness of GraphQL.

OAP has implemented gRPC Health Checking Protocol. We could use grpc-health-probe or any other tools to check the health of OAP gRPC services.