The Uptime Engineer
👋 Hi, I am Yoshik Karnawat
You’ll see how teams are using eBPF today to debug latency in production, enforce zero-trust networking between services, and catch real attacks at the syscall level. Instead of abstract theory, you’ll walk through concrete examples from tools like Cilium, Pixie, and Falco, and understand exactly where they plug into the Linux kernel. By the end, you’ll know when to reach for eBPF, what problems it actually solves better than traditional agents, and how to explain those tradeoffs in interviews without sounding like a manual.
Quick question: when did we start trusting user code to run inside the Linux kernel?
eBPF (Extended Berkeley Packet Filter) is rewriting the rules of observability, networking, and security by letting you inject custom programs directly into kernel space.
Safely. Dynamically. Without kernel modules.
If you're still copying tcpdump output into Slack or guessing at performance bottlenecks with top, eBPF tools like Cilium, Pixie, and Falco are already replacing your stack.
Here's how this invisible revolution actually works.
What eBPF Actually Does
Traditional observability lives in userspace.
You run a process → it reads /proc or calls syscalls → it exports metrics → Prometheus scrapes them.
This works. But it's slow, incomplete, and blind to kernel internals.
eBPF flips this.
It runs verified bytecode programs inside the kernel. Programs that hook into:
Network packet processing
System calls
File I/O
CPU scheduler events
Memory allocation
Think of it as injecting tiny sensors directly into the operating system's bloodstream.
No recompiling kernels. No reboots. No crashes.
How eBPF Programs Run Safely
Here's the problem eBPF solves:
Kernel modules have full access to everything. One bad pointer and your server dies.
eBPF programs are sandboxed and verified before execution.
The Safety Pipeline:
Write in C (or higher-level abstractions like BCC/libbpf)
Compile to eBPF bytecode
Submit to kernel verifier
Verifier checks:
No infinite loops
No out-of-bounds memory access
Terminates in bounded time
No unsafe kernel function calls
JIT-compiled to native code (if verification passes)
Attached to kernel hook points (kprobes, tracepoints, XDP, etc.)
If verification fails, the kernel rejects it. Your system stays up.
This is the breakthrough: userspace control with kernel-level visibility, zero risk.
Three Real-World Use Cases
1. Tracing (Performance Debugging)
Before: strace attaches to a process and slows it down 10x. Not viable in prod.
With eBPF: Tools like bpftrace let you trace syscalls, function latency, and stack traces at near-zero overhead.
Example: Find which process is causing disk I/O spikes.
bpftrace -e 'tracepoint:block:block_rq_issue { @[comm] = count(); }' Kernel-level visibility. No app changes. Sub-millisecond impact.
2. Networking (Packet Processing)
Before: iptables rules process packets in kernelspace, but slowly and in fixed order.
With eBPF (XDP): Programs run at the NIC driver level before the kernel networking stack even sees the packet.
Cilium uses eBPF to replace kube-proxy entirely:
Service load balancing in the kernel
Native pod-to-pod encryption
L7-aware network policies
Why it matters: Sub-microsecond packet processing. No user/kernel context switches.
3. Security (Runtime Threat Detection)
Before: Security tools scan logs after the fact. Attacks happen in milliseconds.
With eBPF: Falco watches kernel events in real time and triggers alerts on:
Unexpected file access (
/etc/shadowread by nginx)Privilege escalation attempts
Suspicious process spawns
Because eBPF hooks into syscalls directly, attackers can't hide from it by manipulating userspace.
It sees what the kernel sees.
The Tooling Ecosystem
Here's the current landscape:
Tool | Purpose | How It Uses eBPF |
|---|---|---|
Cilium | Kubernetes networking & security | XDP-based load balancing, network policies |
Pixie | Auto-instrumented observability | Traces syscalls, network, app layer without SDKs |
Falco | Runtime security monitoring | Detects kernel-level threats in real time |
bpftrace | Ad-hoc performance tracing | One-liners for debugging prod issues |
Katran | L4 load balancer (Facebook) | eBPF-based packet forwarding |
All of these would've required custom kernel modules 5 years ago.
Now they deploy as userspace binaries.
Why This Matters for SREs
eBPF gives you three things traditional monitoring can't:
Complete visibility - See every syscall, packet, and function call
Zero instrumentation - No code changes, no agents in containers
Production-safe - Kernel verifier guarantees safety
If you're debugging performance, enforcing network policies, or hunting threats, eBPF is the new default.
The kernel is no longer a black box.
One Last Thing
If you want to get hands-on:
Start with bpftrace for quick wins (one-liners to diagnose prod issues).
Then explore Cilium if you run Kubernetes.
And if security is your domain, spin up Falco and watch it catch suspicious behavior you didn't know was happening.
eBPF isn't the future. It's already running in your cloud provider's infrastructure.
Until next time,
Yoshik K
Helpful Resources
eBPF Ecosystem Progress in 2024–2025: A Technical Deep Dive
https://eunomia.dev/blog/2025/02/12/ebpf-ecosystem-progress-in-20242025-a-technical-deep-dive/Understand eBPF Security: Deep Visibility & Real-Time Threat
Track System Call Latency
https://phb-crystal-ball.org/track-system-call-latency/A comparison of eBPF Observability vs Agents and Sidecars
https://medium.com/@samyukktha/a-comparison-of-ebpf-observability-vs-agents-and-sidecars-3263194ab757