  Cloud-native containerized applications constantly seek high-performance and
easy-to-operate container network solutions. RDMA network is a potential
enabler with higher throughput and lower latency than the standard TCP/IP
network stack. However, several challenges remain in equipping containerized
applications with RDMA network: 1) How to deliver transparent improvements
without modifying application code; 2) How to integrate RDMA-based network
solutions with container orchestration systems; 3) How to efficiently utilize
RDMA for container networks.
  In this paper, we present an RDMA-based container network solution, TCP
Socket over RDMA (TSoR), which addresses all the above challenges. To
transparently accelerate applications using POSIX socket interfaces without
modifications, we integrate TSoR with a container runtime that can intercept
system calls for socket interfaces. To be compatible with orchestration systems
like Kubernetes, TSoR implements a container network following the Kubernetes
network model and satisfies all requirements of the model. To leverage RDMA
benefits, TSoR designs a high-performance network stack that efficiently
transfers TCP traffic using RDMA network. Thus, TSoR provides a turn-key
solution for existing Kubernetes clusters to adopt the high-performance RDMA
network with minimal effort.
  Our evaluation results show that TSoR provides up to 2.3x higher throughput
and 64\% lower latency for existing containerized applications, such as Redis
key-value store and Node.js web server, with no code changes. TSoR code will be
open-sourced.
