Copyright © 2017 Mounic Madiraju
Apache License
Fester is a metrics aggregator consisting of a Storm service which reads from a Kafka queue and emits events through a topology which looks like the below:
In Fester, the raw metrics are saved to Cassandra immediately. Kafka ensures that all metrics are seen by fester and Storm allows for processing each metric at least once.
The metric key is used as the fields mapping value, so that the bolts which rollup or receive raw metrics can be scaled horizontally by setting an increased worker count.
The rollup bolts collect events for their period, write an aggregated value to a rollup table and then emit an aggregated event. This means we can chain any number of aggregation types and aggregation periods together.