Splunk binary can be used to convert the instance into to Splunk Light Forwarder or Splunk Heavy Forwarder. Both these roles are different than Splunk Universal Forwarder. After installation of the instance, enabling any of the LF or SplkFwdr app, turns off the WebUI and converts the instance in to the role defined within these Apps.
On the other hand, "sample_app" is used to create custom apps. While creating a custom app, Splunk UI Wizard prompts to select "barebones" or "sample_app" to choose from.
Will dig more for 'legacy' app and update the post again.
- Mitesh Vohra.
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