eBPF for Cloud-Native Security and Observability

Why Traditional K8s Security Hits a Wall

For years, securing a Kubernetes cluster meant accepting difficult trade-offs. You either injected heavy sidecar containers (like Envoy) into every pod or loaded custom kernel modules to intercept traffic at the host level.

Sidecars quickly consume memory and CPU across large clusters, while custom kernel modules introduce stability risks a bug in kernel space can crash the entire node.

eBPF (Extended Berkeley Packet Filter) changes this equation by enabling clean inspection and processing of events directly within the kernel.

How eBPF Works

eBPF allows you to execute sandboxed programs directly inside the Linux kernel without modifying kernel source code or loading unstable modules. Because eBPF programs execute right where kernel events occur, you gain deep visibility into system behavior:

• Low-overhead observability: Kernel-level tracing captures system calls, file access, and network packets across the entire host without needing sidecar injection.
• Safer network enforcement: Security tools filter or drop unwanted packets at line rate before they pass through the full K8s networking stack.
• Low-overhead profiling: eBPF profilers trace CPU spikes down to specific application call stacks in production with minimal performance overhead.

Cilium and the CNI Shift

If you are provisioning a Kubernetes cluster today on Proxmox, AWS, or bare metal, Cilium has become a highly compelling CNI option. By utilizing eBPF to bypass or streamline standard kube-proxy iptables rules, Cilium reduces latency and boosts network throughput for service-to-service traffic.

Summary

eBPF redefines how cloud-native networking, monitoring, and security operate. By safely shifting inspection into the kernel, it eliminates much of the overhead that burdened sidecar architectures. Understanding how eBPF works is rapidly becoming essential knowledge for anyone managing production Kubernetes infrastructure.