I often ask: can one lightweight tool give you kernel-level visibility without slowing your systems?

We’ll show how a modern runtime approach brings real-time monitoring to where your applications run. I’ll explain how an eBPF-based driver runs verified programs safely inside the linux kernel and streams events to a user-space engine.

That stream is evaluated against clear rules so you get timely alerts—actionable information at the right time, not noise after an incident.

We keep this hands-on. I’ll walk you through how the system and container worlds are covered, sensible install steps, and basic tuning so your team sees signal, not alerts you ignore.

Key Takeaways

• Get kernel-level visibility with minimal overhead for modern runtime security.
• An eBPF driver streams system events to a user-space engine that evaluates rules.
• Practical install steps and sensible defaults make adoption fast and safe.
• One tool can monitor both containers and traditional hosts without trade-offs.
• Community-tested defaults and tuning help reduce noise and increase trust.

Why Falco and eBPF matter for runtime security today

When code runs in production, you need tools that watch actions in real time.

We focus on runtime visibility because policies and scans help before deploy, but they don’t see what happens at run time. Observing system calls and other kernel events gives immediate context when something odd occurs—like an unexpected shell or strange file writes.

The modern approach places verified programs inside the linux kernel so hooks can inspect process, file, and network behavior with minimal overhead. The kernel’s verifier and JIT compilation protect host stability while keeping performance high across containers, VMs, and the cloud.

Compared to older kernel module methods, this path reduces risk and increases compatibility. In real-world cases, rules spot lateral movement and unusual access patterns even when signature-based detection fails.

We also value the community and the steady stream of features and rules it ships. That means faster, usable output you can route to your on-call stack—so teams get timely alerts they can act on without drowning in noise.

How eBPF powers low‑overhead security monitoring inside the Linux kernel

From packet filter to sandbox: the technology started as a packet filter and now runs tiny verified programs inside kernel space. The kernel hosts a small virtual machine that accepts C code compiled with LLVM/Clang, then verifies the bytecode to avoid loops and invalid memory access.

The verifier enforces safety before any native translation. After verification a JIT turns bytecode into native code so probes run fast and predictably.

Observing system calls and other kernel events without instability

Hooks attach to tracepoints, kprobes, uprobes, and system call entry/exit to capture relevant events. That lets us watch system calls and file or network actions without loading risky modules or crashing the host.

User space to kernel space data paths: maps, ring buffers, and output

Data moves via two main paths. Maps provide lightweight key-value sharing for counters and state.

Ring buffers stream high-volume output per CPU to user space. This keeps the runtime engine fed with rich context while keeping CPU use low.

• Verified programs run safely in kernel space.
• Maps store short-lived context and counters.
• Ring buffers deliver high-throughput event streams to user space.

The net result: line-rate visibility into system activity with minimal overhead — a practical, stable way to observe events and act on them quickly.

Inside Falco’s architecture: drivers, probes, and the rule engine

I’ll map how kernel-level capture becomes readable alerts in user space.

At the kernel edge a driver captures a rich stream of system activity. That stream includes system call entry/exit, context switches, process termination, page faults, and signals.

In user space libscap reads those events and hands them to libsinsp. libsinsp enriches each record with process, container, and namespace context so the engine can evaluate meaningful conditions.

The rules engine evaluates conditions against enriched data. When a rule matches, the engine emits an output you can route to logs, webhooks, or monitoring tools.

There are two probe paths: the modern probe and a legacy kernel module. The community is also building a CO‑RE approach so a single compiled program and code work across kernel versions for easier portability.

• Kernel-side capture feeds user-space inspection.
• Enrichment adds process and container context.
• Rules turn matching events into actionable output.

Getting started fast: install Falco and use eBPF on your Linux systems

Ready to get hands-on? I’ll show a fast path to run the tool on both hosts and containers so you see kernel events in real time.

Docker quick start: copy-paste a Docker run that mounts critical host paths and runs with –privileged so the probe can access the kernel.

• Mount /var/run/docker.sock, /proc, /boot, /lib/modules, and /usr from the host.
• Run the container with –privileged to grant kernel access for probes.
• Use the provided image and arguments to stream events into user space immediately.

Host and VPS install

If you prefer installing on the host, the official install.sh detects your linux kernel and enables the modern driver by default on kernels 4.14+.

The installer sets up the program and the small legacy module if needed. On immutable hosts the eBPF path keeps footprint minimal and avoids extra modules.

Verify the driver and output

Use the CLI to confirm the probe is loaded and events flow to user space. Within seconds you should see system and file events appear as output.

Quick sanity checks: confirm mounted files for symbol resolution, check driver status via the tool, and watch for rules firing in real time.

Falco eBPF security

A few well-crafted rules can turn raw kernel events into alerts your team trusts.

Writing rules starts with the defaults. The YAML files include macros and lists you can reuse to keep rules readable as complexity grows.

Start by enabling defaults that detect shells in containers, sensitive file writes, and package manager runs. Then add environment-specific exceptions to cut noise.

Writing and tuning rules for system, file, and network events

Focus on practical patterns: detect a shell spawn in a container, unexpected writes under /etc, or odd process trees. Use macros to group checks and lists to whitelist known management tools.

• Keep conditions simple and anchored to process, file, or network context.
• Suppress benign updates and known cron jobs to reduce false positives.
• Include pod, namespace, and container identifiers in outputs for fast triage.

Routing alerts to Slack, webhooks, and services with Falcosidekick

Forward enriched alerts to Slack, webhooks, queues (Kafka, NATS), or on-call tools like PagerDuty with minimal setup. The connector maps output fields so each message includes namespace, pod, and process details.

With careful rule design and targeted routing, you get focused detections and context-rich messages—so teams act fast and with confidence.

Performance, safety, and stability: kernel module vs eBPF

Performance and stability hinge on how code runs inside the kernel, so choose capture wisely.

A classic kernel module runs unrestricted and can give deep hooks into kernel space. That power comes with risk: a buggy module can crash hosts or corrupt state.

Verification, JIT, and reduced overhead for real‑time monitoring

Modern verified programs are checked before they run. The verifier blocks invalid memory access and unbounded loops, then a JIT turns bytecode into fast native code.

Measurements from Sysdig show the modern approach has overhead very close to a kernel module and far below ptrace or auditd tracers. In short, you get steady hosts even during event bursts while keeping useful visibility for investigation.

• The old module gives power but increases operational risk.
• Verified programs limit what runs inside kernel space, reducing crash potential.
• JIT-compiled code delivers low latency for real-time monitoring.

There are cases where a module still appears for compatibility. I recommend the verified path by default — it lowers operational risk and preserves performance at production scale. Tools like Falco enable that default to keep teams productive and confident.

Real‑world coverage: containers, Kubernetes, and cloud environments

Seeing how containers behave in flight makes investigations far simpler.

I translate kernel-level detections into everyday operations you already understand.

That means spotting a shell started inside a container, odd file writes under /etc, or unexpected outbound network calls tied to a process or pod.

Detecting shells, file access, and network calls in containers

We map common attacker behaviors to clear rules so alerts are actionable.

Examples: package manager execs, writes to sensitive files, or probes of the Kubernetes API are surfaced with pod and process context.

Extending visibility with plugins for Kubernetes and cloud audit events

Beyond system calls, plugins pull in Kubernetes audit events, AWS CloudTrail, Docker, and GitHub activity.

Those inputs let rules span layers and link a pod-level action to a control‑plane or cloud event.

• Deploy one instance per node (DaemonSet) so every container workload is observed.
• Correlate kernel events with cloud audit logs for faster root cause analysis.
• Keep outputs unified so your alerting and SIEM pipelines receive consistent fields.

Best practices in 2025: rules, filtering, and noise reduction

Manage rules like code: small, reviewed changes reduce noise and risk. I recommend starting with the defaults, then iterating as you learn normal user behavior.

Keep rules focused. Use macros and lists in YAML so repeated logic stays readable and easy to audit. That reduces accidental broad matches and keeps outputs useful.

Track time-based patterns. Scheduled jobs and maintenance windows explain many spikes—capture that context in allowlists rather than disabling detections globally.

Balancing defaults with environment exceptions

Enable disabled-by-default detections only after you add allowlists for known tools and trusted paths. This keeps true positives high while cutting noise.

Leveraging the community and continuous updates

Adopt falcoctl to deploy rule and plugin updates across your fleet. The community publishes new features and curated rules that speed coverage for new cases.

Final note: review file and system behaviors unique to your stack regularly, and validate rules after kernel or runtime upgrades to keep runtime security effective.

Move forward with Falco: implement runtime security that keeps pace

Begin with a single rule and a single node to prove runtime monitoring works for your systems.

Install Falco via Docker or native packages, enable the driver, and watch kernel events stream into your user space. Route output to an on-call service or webhook so early alerts land where teams act.

Bring the tool to your machines—bare metal, VMs, and containers all benefit from the same behavioral lens on calls, files, processes, and network activity.

One focused step: add one rule, review alerts, then iterate. The driver and kernel module options exist, but using eBPF offers safer portability. Do this now and make runtime monitoring part of your regular ops.