A High Performance, Scalable DNS Service for Very Large Scale Container Cloud Platforms

Containers and microservices are dominating the world of data center and cloud computing. As the scale, dynamism and complexity grow, the performance of the DNS system in container clusters becomes vital. As the world's third and China's largest e-commerce site by revenue, JD.com runs one of the world's largest Kubernetes container clusters in production. It is imperative that the DNS system can handle extremely high traffic. In this paper, we present ContainerDNS, a high performance DNS system for very large scale container clusters with millions of containers. ContainerDNS maximizes DNS system performance and scalability by optimizing DNS packet processing and using efficient memory and cache management. ContainerDNS has been deployed in JD's container platform with 30,000 servers and 500,000 containers running tens of thousands of services and applications. It improves the maximum throughput from 130,000 to 9,000,000 QPS, a 67X performance boost comparing to existing DNS systems.