It's commonly used in conjunction with Elasticsearch, a Lucene based search service, and Kibana, a dashboard UI for Elasticsearch. You can easily consider this as a "Splunk without super awesome ad hoc query capabilities" but the software itself is FREE so there's that.
The documentation for Logstash is pretty straightfoward, but I thought it would be nice to have some hard examples to work off of that involved the whole ELK stack:
Right now it just has two examples: file and log4j.
- Write to a file
- Logstash monitors the specific file and does some grokking before passing it to Elasticsearch
- Load the provided kibana dashboard.
- Spew log4j stuff out with SocketAppender
- Set up Logstash to monitor a port for log4j messages and grok before passing it to Elasticsearch
- load the provided Kibana dashboard
So yeah I hope this serves as a quick and easy way for people to observe the awesomeness that is Logstash. Feel free to add your own examples to this guy as well.