Set up a test application for a Tempo cluster

Once you’ve set up a Grafana Tempo cluster, you need to write some traces to it and then query the traces from within Grafana. This procedure uses Tempo in microservices mode. For example, if you set up Tempo using the Kubernetes with Tanka procedure, then you can use this procedure to test your set up.

Before you begin

You’ll need:

Grafana 10.0.0 or higher
Microservice deployments require the Tempo querier URL, for example: http://tempo-cluster-query-frontend.tempo.svc.cluster.local:3100/
OpenTelemetry telemetrygen for generating tracing data

Refer to Deploy Grafana on Kubernetes if you are using Kubernetes. Otherwise, refer to Install Grafana for more information.

Configure Grafana Alloy to remote-write to Tempo

This section uses a Grafana Alloy Helm chart deployment to send traces to Tempo.

To do this, you need to create a configuration that can be used by Alloy to receive and export traces in OTLP protobuf format.

Create a new values.yaml file which we’ll use as part of the Alloy install.

Edit the values.yaml file and add the following configuration to it:

alloy:
  extraPorts:
    - name: otlp-grpc
      port: 4317
      targetPort: 4317
      protocol: TCP
  configMap:
    create: true
    content: |-
      // Creates a receiver for OTLP gRPC.
      // You can easily add receivers for other protocols by using the correct component
      // from the reference list at: https://grafana.com/docs/alloy/latest/reference/components/
      otelcol.receiver.otlp "otlp_receiver" {
        // Listen on all available bindable addresses on port 4317 (which is the
        // default OTLP gRPC port) for the OTLP protocol.
        grpc {
          endpoint = "0.0.0.0:4317"
        }

        // Output straight to the OTLP gRPC exporter. We would usually do some processing
        // first, most likely batch processing, but for this example we pass it straight
        // through.
        output {
          traces = [
            otelcol.exporter.otlp.tempo.input,
          ]
        }
      }

      // Define an OTLP gRPC exporter to send all received traces to GET.
      // The unique label 'tempo' is added to uniquely identify this exporter.
      otelcol.exporter.otlp "tempo" {
          // Define the client for exporting.
          client {
              // Send to the locally running Tempo instance, on port 4317 (OTLP gRPC).
              endpoint = "http://tempo-cluster-distributor.tempo.svc.cluster.local:4317"
              // Disable TLS for OTLP remote write.
              tls {
                  // The connection is insecure.
                  insecure = true
                  // Do not verify TLS certificates when connecting.
                  insecure_skip_verify = true
              }
          }
      }

Ensure that you use the specific namespace you’ve installed Tempo in for the OTLP exporter. In the line:

endpoint = "http://tempo-cluster-distributor.tempo.svc.cluster.local:3100"

change tempo to reference the namespace where Tempo is installed, for example: http://tempo-cluster-distributor.my-tempo-namespaces.svc.cluster.local:3100.

Deploy Alloy using Helm:
bash
```
helm install -f values.yaml grafana-alloy grafana/alloy
```
If you deploy Alloy into a specific namespace, create the namespace first and specify it to Helm by appending --namespace=<grafana-alloy-namespace> to the end of the command.

Create a Grafana Tempo data source

To allow Grafana to read traces from Tempo, you must create a Tempo data source.

Navigate to Connections > Data Sources.
Click on Add data source.
Select Tempo.
Set the URL to http://<TEMPO-QUERY-FRONTEND-SERVICE>:<HTTP-LISTEN-PORT>/, filling in the path to the Tempo query frontend service, and the configured HTTP API prefix. If you have followed the Deploy Tempo with Helm installation example, the query frontend service’s URL looks something like this: http://tempo-cluster-query-frontend.<namespace>.svc.cluster.local:3100
Click Save & Test.

You should see a message that says Data source is working.

Visualize your data

After you have created a data source, you can visualize your traces in the Grafana Explore page. For more information, refer to Tempo in Grafana.

Use OpenTelemetry `telemetrygen` to generate tracing data

You can use OpenTelemetry telemetrygen to generate tracing data to test your Tempo installation.

These instructions use the endpoints for both Grafana Alloy and the Tempo distributor used previously, for example:

grafana-alloy.grafana-alloy.svc.cluster.local for Grafana Alloy
tempo-cluster-distributor.tempo.svc.cluster.local for the Tempo distributor

Update the endpoints if you have altered the endpoint targets.

Install telemetrygen using the installation procedure. NOTE: You don’t need to configure an OpenTelemetry Collector because we’re using Grafana Alloy.

Generate traces using telemetrygen:

telemetrygen traces --otlp-insecure --rate 20 --duration 5s --otlp-endpoint grafana-alloy.grafana-alloy.svc.cluster.local:4317

This configuration sends traces to Alloy for 5 seconds, at a rate of 20 traces per second.

Optionally, you can also send the trace directly to the Tempo database without using Alloy as a collector by using the following:

telemetrygen traces --otlp-insecure --rate 20 --duration 5s --otlp-endpoint tempo-cluster-distributor.tempo.svc.cluster.local:4317

If you’re running telemetrygen on your local machine, ensure that you first port-forward to the relevant Alloy or Tempo distributor service, for example:

kubectl port-forward services/grafana-alloy 4317:4317 --namespace grafana-alloy

Alternatively, a cronjob can be created to send traces periodically based on this template:

apiVersion: batch/v1
kind: CronJob
metadata:
  name: sample-traces
spec:
  concurrencyPolicy: Forbid
  successfulJobsHistoryLimit: 1
  failedJobsHistoryLimit: 2
  schedule: "0 * * * *"
  jobTemplate:
    spec:
      backoffLimit: 0
      ttlSecondsAfterFinished: 3600
      template:
        spec:
          containers:
          - name: traces
            image: ghcr.io/open-telemetry/opentelemetry-collector-contrib/telemetrygen:v0.96.0
            args:
              - traces
              - --otlp-insecure
              - --rate
              - "20"
              - --duration
              - 5s
              - --otlp-endpoint
              - grafana-alloy.grafana-alloy.svc.cluster.local:4317
          restartPolicy: Never

To view the tracing data:

Go to Grafana and select Explore.
Select the Tempo data source from the list of data sources.
Select the Search Query type.
Select Run query.
Confirm that traces are displayed in the traces Explore panel. You should see 5 seconds worth of traces, 100 traces in total per run of telemetrygen.

Test your configuration using the Intro to MLTP application

The Intro to MLTP application provides an example five-service application generates data for Tempo, Mimir, Loki, and Pyroscope. This procedure installs the application on your cluster so you can generate meaningful test data.

Navigate to https://github.com/grafana/intro-to-mltp to get the Kubernetes manifests for the Intro to MLTP application.

Clone the repository using commands similar to the ones below:

  git clone git+ssh://github.com/grafana/intro-to-mltp
  cp intro-to-mltp/k8s/mythical/* ~/tmp/intro-to-mltp-k8s

Change to the cloned repository: cd intro-to-mltp/k8s/mythical
In the mythical-beasts-deployment.yaml manifest, alter each TRACING_COLLECTOR_HOST environment variable instance value to point to the Grafana Alloy location. For example, based on Alloy installed in the default namespace and with a Helm installation called test:
yaml
```
 	- env:
     ...
     - name: TRACING_COLLECTOR_HOST
       value: grafana-alloy.grafana-alloy.svc.cluster.local
```

Deploy the Intro to MLTP application. It deploys into the default namespace.

    kubectl apply -f mythical-beasts-service.yaml,mythical-beasts-persistentvolumeclaim.yaml,mythical-beasts-deployment.yaml

Once the application is deployed, go to Grafana Enterprise and select the Explore menu item.
Select the Tempo data source from the list of data sources.
Select the Search Query type for the data source.
Select Run query.
Traces from the application will be displayed in the traces Explore panel.