Logstash is a system that receives, processes and outputs logs in a structured format. By sending a string of information, you receive a structured and enriched JSON format of the data. One of Logstash’s main uses is to index documents in data stores that require structured information, most commonly Elasticsearch. For example, if you send, “Hello world”, in a string to Logstash, you will receive a JSON output. By default, this structured information of key values will include the message, “Hello world”, a timestamp of when the message was received, a host name from the source of the message, and a version.
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