🧠 What is eBPF?

eBPF (extended Berkeley Packet Filter) is a powerful Linux kernel technology that allows safe, sandboxed programs to run inside the kernel — without modifying kernel code or loading unsafe modules.

It effectively allows you to:

🔍 Observe, control, and optimize kernel-level behavior dynamically and safely.

🔧 What eBPF Can Do

Use Case Example
🔎 Observability Track network calls, CPU/memory usage, syscall latencies
🔒 Security Monitor or block suspicious system calls, container activity
🌐 Networking Build firewalls, traffic shaping, load balancers (e.g. Cilium)
⚙️ Profiling Live CPU flamegraphs, stack traces, I/O bottlenecks
🧪 Tracing Distributed tracing with low overhead (e.g. Coroot, Pixie)

📦 How It Works (Simplified)

  1. You write a tiny program (in C or use a tool like bpftrace).
  2. It’s compiled into eBPF bytecode.
  3. The kernel verifies the code (ensures it’s safe).
  4. It’s loaded into the kernel and hooked to an event (e.g., network packet, syscall, tracepoint).
  5. It runs in a sandboxed VM inside the kernel with near-zero overhead.

🔐 Why It’s Safe

  • eBPF code is verified before execution.
  • It runs in a sandbox (no memory access outside bounds).
  • It cannot crash the kernel.

🔥 eBPF Power Examples

  • bcc / bpftrace → Observe kernel-level events (like strace++ on steroids)
  • Pixie / Coroot → Use eBPF to trace services and monitor latency without instrumenting code
  • Cilium → An eBPF-powered networking and security layer for Kubernetes

📌 Summary

eBPF = kernel superpower for visibility, security, and performance — used by modern tools like Coroot, Pixie, Cilium, and more.