CHERUB - an energy saving daemon for HPC- and SLB-clusters

Compute clusters are often managed by a so-called Resource Management System (RMS) which has load information about the whole system. CHERUB is a centralized daemon which is installed on top of an arbitrary RMS and uses its load information to switch on/off nodes according to the current load situation and load forecasting to save energy in this way. Due to its modular design and its well defined API it can operate with different Resource Management Systems. At the Moment there are modules available for the Portable Batch System (PBS), the Load Sharing Facility (LSF) and the IBM Load Leveler (LL) in the High Performance Compute (HPC) field and for the Linux Virtual Server (LVS) in the Server Load Balancing (SLB) field.
CHERUB uses 5 internal states to manage the nodes of a cluster. The relation between these states can be seen in Fig.1 below.

cherub statediagram
Fig.1: Different Cherub States

Our experimental results shown in Fig. 2 and 3 prove that Cherubs energy management works fine, i.e. it will save energy if possible (Fig. 2) and avoids state-flipping (Fig. 3). Within the experiment node001-node008 where configured to be powered on all the time. While the cluster was doing normal business CHERUB was able to save around 48% of energy (not considering the always on nodes).

cherub savings in one month
Fig.2: Energy Saved with CHERUB
cherub avoids state-flipping
Fig.3: Downtime of nodes when managed with CHERUB

At the moment, Cherub is used on the cluster of the Institute of Computer Science at the University of Potsdam (cluster managed by the Portable Batch System (PBS)) and the German Research Centre for Geosciences at Potsdam (cluster managed by the Load Sharing Facility (LSF)).
Current development efforts are focused on optimizing the Linux Virtual Server module for Server Load Balancing scenarios by using load forecasting and backup features.


The current version (1.3.11) of Cherub can be found here.


If you have any questions regarding CHERUB feel free to contact the developer at simon.kiertscher(at)cs.uni-potsdam.de.


Publications - HPC

Power Consumption Aware Cluster Resource Management
Simon Kiertscher, Jörg Zinke and Bettina Schnor
Bookchapter in Energy-Aware Systems and Networking for Sustainable Initiatives, ISBN-13: 9781466618428
IGI-Global, December 2012


CHERUB: power consumption aware cluster resource management
Simon Kiertscher, Jörg Zinke and Bettina Schnor
Journal of Cluster Computing, ISSN: 1386-7857
Springer Netherlands, September 2011


Cherub: Power Consumption Aware Cluster Resource Management
Simon Kiertscher, Jörg Zinke, Stefan Gasterstädt and Bettina Schnor
IEEE/ACM International Conference on Green Computing and Communications
Hangzhou, China, December 2010


Publications - SLB

Scalability Evaluation of an Energy-Aware Resource Management System for Clusters of Web Servers
Simon Kiertscher and Bettina Schnor
International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS)
Chicago, USA, July 2015


Energy Aware Resource Management for Clusters of Web Servers
Simon Kiertscher and Bettina Schnor
IEEE International Conference on Green Computing and Communications, page 148-156
Beijing, China, August 2013