Monitoring and configuration are two separate things here.
Flume is typically monitored using either ganglia or http/json.
Both methods are documented here:http://flume.apache.org/FlumeUserGuide.html#monitoring
As for configuration management and changes a common way of handling this would be to
use a configuration management tool such as chef, puppet or ansible.
The agent polls the conf file every 30 seconds and if changes are detected than the necessary components will be dynamically reloaded.
Not sure why Kafka is being mentioned as that is an entirely separate project which has nothing to do with flume.