Realizing Network-Attached FPGAs in the Cloud

The Open Cloud Testbed (OCT) has the goal to provide bare-metal resources to the systems research community. In contrast to other infrastructures that offer such resources, the field-programmable gate arrays (FPGAs) in OCT expose their network interface directly to the experimenter, unlocking new possibilities for researchers focusing on cloud application acceleration and data center disaggregation. OCT provides two models for programming network-attached FPGAs. The first grants users direct access to the network interface. The features of this approach are demonstrated with examples that make use of User Datagram Protocol (UDP) and Transmission Control Protocol stacks. An example involving UDP is highlighted that facilitates a distributed machine learning (ML) application. The second model allows FPGA network interface programming via Programming Protocol-Independent Packet Processors, thus providing the FPGA with smart network interface card capabilities. In addition, this article outlines future research directions into network-attached FPGAs, including the security of such systems.