Monitoring is a small aspect of our operational needs; configuring, monitoring, and checking the configuration of tools such as Fluentd and Fluentbit can be a bit frustrating, particularly if we want to validate more advanced configuration that does more than simply lift log files and dump the content into a solution such as OpenSearch. Fluentd and Fluentbit provide us with some very powerful features that can make a real difference operationally. For example, the ability to identify specific log messages and send them to a notification service rather than waiting for the next log analysis cycle to be run by a log store like Splunk. If we want to test the configuration, we need to play log events in as if the system was really running, which means realistic logs at the right speed so we can make sure that our configuration prevents alerts or mail storms.
The easiest way to do this is to either take a real log and copy the events into a new log file at the speed they occurred or create synthetic events and play them in at a realistic pace. This is what the open-source LogGenerator (aka LogSimulator) does. I created the LogGenerator a couple of years ago, having addressed the same challenges before and wanting something that would help demo Fluentd configurations for a book (Logging in Action with Fluentd, Kubernetes, and more).