The plugin-driven server agent for collecting and reporting metrics by Influxdata.
The Technology Addon for Influxdata Telegraf provides indexing time parsing definitions and pre-built panels to ingest Telegraf metrics to the Splunk metric store.
The TA is only required at indexing time (Indexers and Intermediate Heavy Forwarders) if you ingest metrics over TCP inputs (telegraf graphite output plugin), Splunk file monitoring (telegraf file output plugin and Splunk UF deployment) or Kafka. (Telegraf Kafka output plugin and Splunk for Kafka connect)
Starting Telegraf Version 1.8, you can use a builtin http outputs that sends metrics to the HTTP Events Collector.
The TA is only required on search heads if you intend to use pre-built panels.
ITSI module for Telegraf OS: https://splunkbase.splunk.com/app/4194
Splunk application for OS monitoring with Telegraf: https://splunkbase.splunk.com/app/4271