To satisfy future computing demands of the Worldwide LHC Computing Grid (WLCG), opportunistic usage of third-party resources is a promising approach. While the means to make such resources compatible with WLCG requirements are largely satisfied by virtual machines and containers technologies, strategies to acquire and disband many resources from many providers are still a focus of current research. Existing meta-schedulers that manage resources in the WLCG are hitting the limits of their design when tasked to manage heterogeneous resources from many diverse resource providers.
To provide opportunistic resources to the WLCG as part of a regular WLCG site, we propose a new meta-scheduling approach suitable for opportunistic, heterogeneous resource provisioning. Instead of anticipating future resource requirements, our approach observes resource usage and promotes well-used resources. Following this approach, we have developed an inherently robust meta-scheduler, COBalD, for managing diverse, heterogeneous resources given unpredictable resource requirements. This paper explains the key concepts of our approach, and discusses the benefits and limitations of our new approach to dynamic resource provisioning compared to previous approaches.