Troubleshoot the Splunk OpenTelemetry Collector 🔗

See the following issues and workarounds for the Splunk Distribution of the OpenTelemetry Collector.

Note

Collector isn’t behaving as expected 🔗

The Collector might experience the issues described in this section.

Collector or td-agent service isn’t working 🔗

If either the Collector or td-agent services are not installed and configured, check these things to fix the issue:

Check that the OS is supported. See Collector requirements and OpenTelemetry’s Operating System for more information
Check that systemd is installed (if using Linux), as explained in Install the Collector for Linux with the installer script
Check that your platform is not running in a containerized environment
Check the installation logs for more details

Collector exits or restarts 🔗

The collector might exit or restart for the following reasons:

Memory pressure due to a missing or misconfigured memory_limiter processor
Improperly sized for load
Improperly configured. For example, a queue size configured higher than available memory
Infrastructure resource limits. For example, Kubernetes

Restart the Splunk Distribution of OpenTelemetry Collector and check the configuration.

Collector doesn’t start in Windows Docker containers 🔗

The process might fail to start in a custom built, Windows-based Docker container, resulting in a “The service process could not connect to the service controller” error message.

In this case, the NO_WINDOWS_SERVICE=1 environment variable must be set to force the Splunk Distribution of OpenTelemetry Collector to start as if it were running in an interactive terminal, without attempting to run as a Windows service.

Collector is experiencing data issues 🔗

You can monitor internal Collector metrics tracking parameters such as data loss or CPU resources in Splunk Observability Cloud’s default dashboards at Dashboards > OpenTelemetry Collector > OpenTelemetry Collector. To learn more about these metrics, see Monitoring in the OpenTelemetry GitHub repo.

The Collector might experience the issues described in this section.

Collector is dropping data 🔗

Data might drop for a variety of reasons, but most commonly for the following reasons:

The collector is improperly sized, resulting in the Splunk Distribution of OpenTelemetry Collector being unable to process and export the data as fast as it is received. See Sizing and scaling for sizing guidelines.
The exporter destination is unavailable or accepting the data too slowly. To mitigate drops, configure the batch processor. In addition, you might also need to configure the queued retry options on activated exporters.

Collector isn’t receiving data 🔗

The collector might not receive data for the following reasons:

Network configuration issues
Receiver configuration issues
The receiver is defined in the receivers section, but not activated in any pipelines
The client configuration is incorrect

Check the logs and Troubleshooting zPages in the OpenTelemetry project GitHub repositories for more information. Note that Splunk only provides best-effort support for the upstream OpenTelemetry Collector.

Collector can’t process data 🔗

The collector might not process data for the following reasons:

The attributes processors work only for “tags” on spans. The span name is handled by the span processor.
Processors for trace data (except tail sampling) only work on individual spans. Make sure your collector is configured properly.

Collector can’t export data 🔗

The collector might be unable to export data for the following reasons:

Network configuration issues, such as firewall, DNS, or proxy support
Incorrect exporter configuration
Incorrect credentials
The destination is unavailable

If you need to use a proxy, see Configure proxy settings for the Collector.

Check the logs and Troubleshooting zPages in the OpenTelemetry project GitHub repositories for more information. Note that Splunk only provides best-effort support for the upstream OpenTelemetry Collector.

Metrics and metadata not available in data forwarding (gateway) mode 🔗

If you don’t see metrics and metadata after manually deploying the Collector in data forwarding (gateway) mode, the agent configuration might be lacking pipelines that use the SignalFx exporter. Follow these steps to review the configuration:

Make sure that your Gateway can listen to requests on ports 6060 and 9943.
Make sure that the agent configuration has a signalfx exporter in a pipeline. The following example shows a signalfx exporter and a pipeline that uses it for sending metrics:

:emphasize-lines: 2,3,4,5,14

exporters:
  signalfx:
      access_token: "${SPLUNK_ACCESS_TOKEN}"
      api_url: "http://${SPLUNK_GATEWAY_URL}:6060"
      ingest_url: "http://${SPLUNK_GATEWAY_URL}:9943"
      sync_host_metadata: true
      correlation:
  # Other exporters

service:
  extensions: [health_check, http_forwarder, zpages]
  pipelines:
      metrics/internal:
            receivers: [prometheus/internal]
            processors: [memory_limiter, batch, resourcedetection]
            exporters: [signalfx]
      # Other pipelines

Report host metrics in APM 🔗

To capture and send relevant data to show correlated infrastructure metrics in the APM service, add the resource/add_environment processor to your configuration.

This processor inserts a deployment.environment span tag to all spans. The APM charts require the environment span tag to be set correctly. Configure this span tag in the instrumentation, but if that is not an option, you can use this processor to insert the required deployment.environment span tag value.

For example:

processors:
  resourcedetection:
    detectors: [system,env,gce,ec2]
    override: true
  resource/add_environment:
    attributes:
      - action: insert
        value: staging
        key: deployment.environment

Extract a running configuration 🔗

Extracting a running configuration saves or stores the contents of a configuration file to logs that you can use to troubleshoot issues. You can extract a running configuration by accessing these ports:

http://localhost:55554/debug/configz/initial
http://localhost:55554/debug/configz/effective

For Linux, the support bundle script captures this information. See Install the Collector for Linux with the installer script for the installer script. This capability is primarily useful if you are using remote configuration options such as Zookeeper where the startup configuration can change during operation.

Check metric data from the command line 🔗

To check whether host metrics are being collected and processed correctly, you can query the Collector for raw data using curl or similar tools from the command line.

On Linux, run curl http://localhost:8888/metrics in your terminal.
On Windows, run "Invoke-WebRequest -URI http://localhost:8888/metrics" in PowerShell.

You can then pipe the output to grep (Linux) or Select-String (Windows) to filter the data. For example, curl http://localhost:8888/metrics | grep service_instance_id retrieves the service instance ID.

You’re getting a “bind: address already in use” error message 🔗

If you see an error message such as “bind: address already in use”, another resource is already using the port that the current configuration requires. This resource could be another application, or a tracing tool such as Jaeger or Zipkin. You can modify the configuration to use another port.

You can modify any of these endpoints or ports:

Receiver endpoint
Extensions endpoint
Metrics address (if port 8888)

Conflicts with port 8888 🔗

If you encounter a conflict with port 8888, you will need to change to port 8889, making adjustments in these two areas:

Add telemetry configuration under the service section:

service:
  telemetry:
    metrics:
      address: ":8889"

Update the port for receivers.prometheus/internal from 8888 to 8889:

receivers:
  prometheus/internal:
    config:
      scrape_configs:
      - job_name: 'otel-collector'
        scrape_interval: 10s
        static_configs:
        - targets: ['0.0.0.0:8889']

If you see this error message on Kubernetes and you’re using Helm charts, modify the configuration by updating the chart values for both configuration and exposed ports.

You’re getting a “pattern not matched” error message 🔗

If you see an error message such as “pattern not matched”, this message is from Fluentd, and means that the <parser> was unable to match based on the log message. As a result, the log message is not collected. Check the Fluentd configuration and update as required.

You’re receiving an HTTP error code 🔗

If an HTTP request is not successfully completed, you might see the following HTTP error codes.

Error code	Description
`401 (UNAUTHORIZED)`	Configured access token or realm is incorrect.
`404 (NOT FOUND)`	Incorrect configuration parameter, like an endpoint or path, or a network, firewall, or port issue.
`429 (TOO MANY REQUESTS)`	Organization is not provisioned for the amount of traffic being sent. Reduce traffic or request increase in capacity.
`503 (SERVICE UNAVAILABLE)`	Check the status page.

Trace collection issues 🔗

Here are some common issues related to trace collection on the Collector.

Test the Collector by sending synthetic data 🔗

You can test the Collector to make sure it can receive spans without instrumenting an application. By default, the Collector activates the Zipkin receiver, which is capable of receiving trace data over JSON.

To test the UI, you can submit a POST request or paste JSON in this directory, as shown in the following example.

curl -OL https://raw.githubusercontent.com/openzipkin/zipkin/master/zipkin-lens/testdata/yelp.json
curl -X POST localhost:9411/api/v2/spans -H'Content-Type: application/json' -d @yelp.json