Building Scalable Systems with eBPF and Cilium

Introduction to Scalability Challenges

Last quarter, our team discovered that our microservices-based application was struggling to scale beyond 10,000 concurrent users. We tried various approaches to optimize performance, but nothing seemed to work until we stumbled upon eBPF and Cilium. Here's what I learned when implementing these technologies in our production environment.

What are eBPF and Cilium?

eBPF (extended Berkeley Packet Filter) is a technology that allows us to run sandboxed programs in the Linux kernel. Cilium, on the other hand, is an open-source project that leverages eBPF to provide a robust and scalable networking solution for containerized applications. When I first tried to integrate eBPF and Cilium, it broke because I didn't understand the nuances of kernel versions and compatibility.

Implementing eBPF and Cilium

To get started with eBPF and Cilium, we needed to upgrade our kernel to a compatible version. We chose Ubuntu 20.04, which supports eBPF out of the box. Then, we installed Cilium using the official installation script. The process was relatively smooth, but we encountered issues with our existing network configuration. My colleague, Jake, suggested that we use a separate network interface for Cilium to avoid conflicts with our existing setup.

Network Security with eBPF and Cilium

One of the primary benefits of using eBPF and Cilium is enhanced network security. Cilium provides a robust network policy framework that allows us to define fine-grained security rules for our application. We were able to reduce our attack surface by implementing network policies that only allow authorized traffic between microservices. However, we discovered that the default policies were too restrictive, and we needed to customize them to fit our specific use case.