The logging comprises of three single components—Logstash, Elasticsearch and Kibana. While Logstash is used to collect the log message from the single components, Elasticsearch is used to store them inside a fulltext index. Kibana offers the front end for accessing this index.

Logging inside Components

Single components should write log messages to a standard output. Docker containers will be configured to send the standard outputs to the Logstash instance.

We encourage the usage of a facade, e.g., slf4j, in the program code. This offers the advantage that a certain implementation, e.g., log4j, can be chosen without influence on the already written code. Additionally, all components should share a single pattern for the log messages to ease the analysis of log messages and the configuration of Kibana.