Kubernetes has emerged as the de facto standard for container orchestration, enabling teams of all sizes to deploy, scale and manage microservices-based applications. Despite its immense flexibility, default settings can become a roadblock as clusters grow and workloads become more demanding.
One prime example is kube-proxy, which handles network traffic by relying on extensive rule management. Let’s explore why relying on kube-proxy can hamper performance and complicate operations, and how Cilium, the only graduated container network interface (CNI) in the CNCF, can alleviate these challenges.
Why Default Configurations Can Be Limiting
Kubernetes is inherently modular. This plug-and-play design fosters a dynamic ecosystem: Teams can choose their preferred container network interface (CNI), ingress controllers or logging mechanisms. While this modularity is a strength, it also adds complexity.
According to tech journalist Bill Doerrfeld’s recent insights, Kubernetes itself continues to grow more intricate, making default settings less effective for organizations pushing the platform to its limits. Though Kubernetes excels at automating many container-related tasks, performance and security needs often exceed what its out-of-the-box components provide. Fortunately, an active community keeps pace through open source contributions and dedicated projects, ensuring Kubernetes evolves to meet real-world production demands.
Enter Cilium, the third most active project in the CNCF (behind Kubernetes and OpenTelemetry). Built on eBPF, Cilium brings modern networking capabilities that directly address many scaling and performance pain points.
Understanding Kube-Proxy’s Challenges
In Kubernetes, the default approach to network traffic is kube-proxy, which typically relies on iptables or IP Virtual Server (IPVS) rules to route requests to services. This abstraction works well for smaller clusters, saving you from manually managing every IP and port, but becomes unwieldy as you scale to dozens or hundreds of nodes and thousands of pods. As rule sets grow exponentially, complexity, latency and operational overhead can quickly mount.
Performance Overheads
By managing vast numbers of forwarding rules, kube-proxy introduces layers of translation for every connection. Although minimal at first, this overhead grows rapidly with the cluster size, often increasing latency and risking connection drops.
Operational Complexity
Updating and debugging iptables or IPVS rules in production is rarely straightforward. Each new or removed service adds more rules, which must be constantly maintained. In teams that push code multiple times a day, this churn quickly drains developer focus, shifting it from feature work to firefighting rule updates and connectivity hiccups.
Limits on Load Balancing
Kube-proxy relies on per-node rules for load balancing, which can be less efficient than direct in-kernel or eBPF-based methods. The constant addition or removal of pods forces each node to rebuild extensive rule sets, creating bottlenecks as your cluster scales.
Enter Cilium: The eBPF-Based Path to Better Networking
Open source Cilium is purpose-built to handle modern, cloud native environments at scale. By leveraging eBPF, it can run custom networking, security and observability features directly in the Linux kernel — bypassing the complexity and overhead of external proxies or massive rule sets.
- Efficiency: eBPF-based data paths reduce latency and improve throughput by handling packets in the kernel.
- Security and observability: Cilium’s deep integration with eBPF enables advanced security policies, real-time traffic insights and the ability to analyze network flows at a granular level.
- Community-backed: As a CNCF-graduated project, Cilium has a broad user base and active contributors, ensuring long-term stability and innovation.
Success Stories With Cilium
From streaming platforms to financial services, organizations around the globe have discovered tangible benefits by adopting Cilium in production. Explore the production use cases from the CNCF customer case studies, showcasing how eBPF-based networking transforms Kubernetes environments.
Going Kube-Proxy Free
How Cilium Eliminates Kube-Proxy
One of Cilium’s standout features is its “kube-proxy replacement” mode. Instead of layering iptables rules on each node, Cilium uses eBPF to load balance traffic in a far more efficient way. Service discovery and routing are performed dynamically inside the kernel, which removes the extra hops that can bog down traffic.
Performance Gains and Simplification
By removing kube-proxy from the path, you reduce the number of moving parts. This simplification leads to improvements in throughput, latency and CPU usage on cluster nodes. Because eBPF-based load balancing doesn’t depend on continuously managing thousands of rules, your networking stack is more responsive — especially in clusters where new services come and go at a rapid clip.
Security and Observability Benefits
A lesser-discussed but equally critical advantage is enhanced security and observability. eBPF lets you insert logic directly into the kernel’s network stack, giving you greater visibility into data flows than typical L3/L4 solutions. This can translate to more comprehensive enforcement of network policies, granular microsegmentation implementations, as well as the ability to capture detailed metrics for debugging or performance analysis.
Conclusion and Next Steps
Kubernetes is designed to be open, powerful and extensible. However, that same flexibility can lead to an overreliance on default components that might not serve you in the long run. Kube-proxy is a prime example: perfectly fine for smaller environments, but quickly outgrown in large-scale, fast-changing clusters.
Cilium’s eBPF-based approach offers a seamless path to drop kube-proxy altogether and unlock more powerful, efficient and secure networking. By running functionality directly in the kernel, eBPF eliminates the heavy rule-based overhead, speeds up traffic and provides deeper visibility. Cilium has demonstrated the maturity, community support and performance to become the de facto standard for cloud native networking.
Ready to learn more? Check out the official Cilium documentation or the Cilium Slack channels to get real-world advice from fellow users and maintainers. Whether you’re operating a handful of nodes or orchestrating massive multicloud deployments, going kube-proxy free with Cilium might just be the next leap forward in your Kubernetes journey.
To learn more about Kubernetes and the cloud native ecosystem, join us at KubeCon + CloudNativeCon Europe in London on April 1-4.
The post Breaking the Chains of Kube-Proxy With Cilium appeared first on The New Stack.
Built on eBPF, container network interface Cilium brings modern networking capabilities that address many scaling and performance pain points.