Logstash is a powerful data processing pipeline tool that can ingest data from multiple sources, transform it, and then send it to different destinations. Even without other components of the Elastic Stack, Logstash can perform the following tasks:

A. Receive log data from remote systems: Logstash can collect logs from various sources using its numerous input plugins, such as beats, syslog, and HTTP.

D. Process log data to extract information: Logstash can process and transform log data using filter plugins, which allow for parsing, enriching, and modifying the data.

E. Forward log data to other services: Logstash can forward processed data to various outputs, such as databases, message queues, and other log management systems.

The other options are not tasks that Logstash can perform without other components:

B. Store log data persistently: Logstash itself does not provide persistent storage capabilities. It requires Elasticsearch or another storage solution to persist the data.

C. Aggregate log data over a period of time: Aggregation typically requires persistent storage and querying capabilities, which Logstash alone does not provide.

References:

Elastic Documentation - Logstash