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Splunk OpenTelemetry Collector

Splunk OpenTelemetry Collector is a distribution of the OpenTelemetry Collector. It provides a unified way to receive, process, and export metric, trace, and log data for Splunk Observability Cloud:

• Splunk APM via the sapm exporter. The otlphttp exporter can be used with a custom configuration. More information available here.
• Splunk Infrastructure Monitoring via the signalfx exporter. More information available here.

While it is recommended to use Splunk Forwarders to send data to Splunk Cloud or Splunk Enterprise, Splunk OpenTelemetry Collector can be configured to send data to them via the splunk_hec exporter.

Current Status

• The Splunk Distribution of the OpenTelemetry Collector is production tested; it is in use by a number of customers in their production environments
• Customers that use our distribution can receive direct help from official Splunk support within SLA's
• Customers can use or migrate to the Splunk Distribution of the OpenTelemetry Collector without worrying about future breaking changes to its core configuration experience for metrics and traces collection (OpenTelemetry logs collection configuration is in beta). There may be breaking changes to the Collector's own metrics.

Getting Started

The following resources are available:

• Architecture: How the Collector can be deployed
• Components: What the Collector supports with links to documentation
• Monitoring: How to ensure the Collector is healthy
• Security: How to ensure the Collector is secure
• Sizing: How to ensure the Collector is properly sized
• Troubleshooting: How to resolve common issues

All you need to get started is:

• Splunk Access Token
• Splunk Realm
• Agent or Gateway mode
• Confirm exposed ports to make sure your environment doesn't have conflicts and that firewalls are configured properly. Ports can be changed in the collector's configuration.

This distribution is supported on and packaged for a variety of platforms including:

• Kubernetes
  • Helm (recommended)
  • Operator (in alpha)
  • YAML
• HashiCorp Nomad
• Linux
  • Installer script (recommended for single-host demo/test environments)
  • Configuration management (recommended for multi-host production environments)
    • Ansible
    • Chef
    • Puppet
    • Salt
  • Platform as a Service
    • Heroku
  • Manual including DEB/RPM packages, Docker, and binary
• Windows
  • Installer script (recommended for single-host demo/test environments)
  • Configuration management (recommended for multi-host production environments)
    • Ansible
    • Chef
    • Puppet
  • Manual including MSI with GUI and Powershell, Chocolatey, and Docker

You can consult additional use cases in the examples directory.

Advanced Configuration

A variety of default configuration files are provided:

• OpenTelemetry Collector see full_config_linux.yaml for a commented configuration with links to full documentation. The logs_config_linux.yaml is a good starting point for using the collector for collecting application logs on Linux environments. agent_config.yaml is the recommended starting configuration for most environments.
• Fluentd applicable to Helm or installer script installations only. See the *.conf files as well as the conf.d directory. Common sources including filelog, journald, and Windows event viewer are included.

In addition, the following components can be configured:

• Configuration sources
  • Environment variables
  • Etcd2
  • Include
  • Vault
  • Zookeeper
• SignalFx Smart Agent
  • Extension offering Collectd and Python extensions
  • Receiver offering the complete set of Smart Agent monitors
  • Information about migrating from the SignalFx Smart Agent can be found here

The Splunk OpenTelemetry Collector provides a sensitive value-redacting, local config server listening at http://localhost:55554/debug/configz/effective that is helpful in troubleshooting. To enable this feature please set the SPLUNK_DEBUG_CONFIG_SERVER environment variable to true. To set the desired port to listen to configure the SPLUNK_DEBUG_CONFIG_SERVER_PORT environment variable.

You can use the environment variable SPLUNK_LISTEN_INTERFACE and associated installer option to configure the network interface on which the collector's receivers and telemetry endpoints will listen. The default value of SPLUNK_LISTEN_INTERFACE is set to 127.0.0.1 for the default agent configuration and 0.0.0.0 otherwise.

Upgrade guidelines

The following changes need to be done to configuration files for Splunk OTel Collector for specific version upgrades. We provide automated scripts included in the bundle that cover backward compatibility on the fly, but configuration files will not be overridden, so you need to update them manually before the backward compatibility is dropped. For every configuration update use the default agent config as a reference.

From 0.96.1 to 0.97.0

• memory_ballast is no longer effective. The garbage collection is now controlled by the soft memory limit set to 90% of total memory (SPLUNK_MEMORY_TOTAL_MIB env var) by default.

  If you haven't customized the memory_ballast, just remove it from the configuration.

  If you have customized it via SPLUNK_BALLAST_SIZE_MIB (or extensions::memory_ballast::size_mib config), you should remove the memory_ballast extension and use the GOMEMLIMIT environment variable to set a custom soft memory limit:

  • To increase frequency of garbage collections: set GOMEMLIMIT to a higher value than the default 90% of total memory.
  • To decrease frequency of garbage collections: set GOMEMLIMIT to a lower value than the default 90% of total memory.

From 0.68.0 to 0.69.0

• gke and gce resource detectors in resourcedetection processor are replaced with gcp resource detector. If you have gke and gce detectors configured in the resourcedetection processor, please update your configuration accordingly. More details: https://github.com/open-telemetry/opentelemetry-collector-contrib/pull/10347

From 0.41.0 to 0.42.0

• The Splunk OpenTelemetry Collector used to evaluate user configuration twice and this required escaping of each $ symbol with $$ to prevent unwanted environment variable expansion. The issue was fixed in 0.42.0 version. Any occurrences of $$ in your configuration should be replaced with $.

From 0.35.0 to 0.36.0

• Configuration parameter "exporters -> otlp -> insecure" is moved to "exporters -> otlp -> tls -> insecure".

  More details: https://github.com/open-telemetry/opentelemetry-collector/pull/4063/.

  Configuration part for otlp exporter should look like this:

  exporters:
    otlp:
      endpoint: "${SPLUNK_GATEWAY_URL}:4317"
      tls:
        insecure: true
  

From 0.34.0 to 0.35.0

• ballast_size_mib parameter moved from memory_limiter processor to memory_ballast extension as size_mib.

  More details: https://github.com/signalfx/splunk-otel-collector/pull/567.

  Remove ballast_size_mib parameter from memory_limiter and make sure that it's added to memory_ballast extension as size_mib parameter instead:

  extensions:
    memory_ballast:
      size_mib: ${SPLUNK_BALLAST_SIZE_MIB}
  

Using Upstream OpenTelemetry Collector

It is possible to use the upstream OpenTelemetry Collector instead of this distribution. The following features are not available upstream at this time:

• Packaging
  • Installer scripts for Linux and Windows
  • Configuration management via Ansible or Puppet
• Configuration sources
• Several SignalFx Smart Agent capabilities

:warning: Splunk only provides best-effort support for upstream OpenTelemetry

In order to use the upstream OpenTelemetry Collector:

• Use the contrib distribution as commercial exporters must reside in contrib
• Properly configure the Collector for your particular metrics, traces, and logs use cases, as only a minimal default configuration is provided by the contrib release.

An example configuration for upstream, that ensures infrastructure correlation is properly configured, is available here.

License

Apache Software License version 2.0.

ℹ️  SignalFx was acquired by Splunk in October 2019. See Splunk SignalFx for more information.