Supporting Mixed Workloads In Openstack-Based Clouds

Currently available open-source cloud management middlewares provide a single service class to allocate computing resources on-demand. The allocation of resources is constrained only by the actual capacity of the infrastructure and usage quotas applied on a per-user basis. Typically, quotas are defined for different users allowing oversubscribed resources, potentially impacting the Quality of Service (QoS) delivered. This is particularly undesirable when mixed workloads with different QoS requirements are submitted to the cloud. We propose a new scheduler for the popular OpenStack middleware which supports multiple service classes. We compared the performance of the proposed scheduler with that of OpenStack's standard scheduler that supports a single service class. Different from the latter, our scheduler handles mixed workloads in a way that the resource utilization is increased, without significantly affecting the QoS guarantees offered to the different service classes.