See http://www.cubrid.org/cluster. CUBRID Cluster is an open source clustered DBMS for high scalability including global schema, distributed partition and load balancing features. It is a spin-off project from CUBRID project and supported by NHN.
OpenJCS (Job Control System) is a batch scheduling and control system for use on Unix systems which uses load balancing, dependency control, scheduling, runbooks, queueing and resource allocation subsystems for unmatched scalability and flexibility.
The underlayer is a symmetric decentralized parallel computing and load balancing framework, providing c, perl and java APIs for distributed job management.