Caladrius is a performance modelling service for Distributed Stream Processing Systems (DSPS) such as Apache Heron and Apache Storm.


The aim of Caladrius is shorten the time taken to scale a topology to the correct size to cope with a given incoming workload (traffic level). With this system, it is hoped, that the plan -> deploy -> stablise -> analyse loop that is currently required to right size a topology, can be shortened.

The ability to predict future workloads also allows the performance of a running topology to be checked against expected high workloads and pre-emptively scaled before the workload arrives.

Further details are provided in the Summary and Background sections.


Caladrius is a prototype project and only implements some the features described above and below. Details of what features have been implemented and what are planned in future are shown on the Road Map.


Caladrius provides a framework to analyse, model and predict the various aspects of DSPS systems (like Apache Heron and Storm) and focuses on two key areas:

The prediction of incoming workload into a DSPS topology. Caladrius provides metrics database interfaces and methods for analysing traffic into a topology and predicting future traffic levels.
Topology Performance:

Predicting how a topology will perform under a given traffic load and for a given cluster layout (physical plan). This breaks down into two further areas:

The prediction of how a topology will perform under a different traffic level if it keeps its current layout.
The prediction of how a topology will perform under the current (or a future) traffic level when its layout is changed.

Indices and tables