DockerCap: A Software-Level Power Capping Orchestrator for Docker Containers

Internet of Things (IoT) is experiencing a huge hype these days, thanks to the increasing capabilities of embedded devices that enable their adoption in new fields of application (e.g. Wireless Sensor Networks, Connected Cars, Health Care, etc.). On the one hand, this is leading to an increasing adoption of multi-tenancy solutions for Cloud and Fog Computing, to analyze and store the data produced. On the other hand, power consumption has become a major concern for almost every digital system, from the smallest embedded circuits to the biggest computer clusters, with all the shades in between. Fine-grain control mechanisms are then needed to cap power consumption at each level of the stack, still guaranteeing Service Level Agreements (SLA) to the hosted applications. In this work, we propose DockerCap, a software-level power capping orchestrator for Docker containers that follows an Observe-Decide-Act loop structure: this allows to quickly react to changes that impact on the power consumption by managing resources of each container at run-time, to ensure the desired power cap. We show how we are able to obtain results comparable with the state of the art power capping solution provided by Intel RAPL, still being able to tune the performances of the containers and even guarantee SLA constraints.