Configuring Logstash

To configure Logstash, you create a config file that specifies which plugins you want to use and settings for each plugin. You can reference event fields in a configuration and use conditionals to process events when they meet certain criteria. When you run logstash, you use the -f to specify your config file.

Let’s step through creating a simple config file and using it to run Logstash. Create a file named "logstash-simple.conf" and save it in the same directory as Logstash.

input { stdin { } }
output {
  elasticsearch { host => localhost }
  stdout { codec => rubydebug }
}

Then, run logstash and specify the configuration file with the -f flag.

bin/logstash -f logstash-simple.conf

Et voilà! Logstash reads the specified configuration file and outputs to both Elasticsearch and stdout. Before we move on to some more complex examples, let’s take a closer look at what’s in a config file.