Introduction to eBPF for Observability

In today's world of intricate software systems, where microservices and distributed architectures reign supreme, observability has become a critical aspect of maintaining operational efficiency and ensuring optimal performance.

eBPF (extended Berkeley Packet Filter) has emerged as a revolutionary technology that provides unprecedented visibility into the inner workings of the Linux kernel, enabling them to effectively monitor, troubleshoot, and optimize their applications and infrastructure.

This technical guide provides a comprehensive introduction to eBPF for observability, delving into its core concepts, practical applications, and popular tools.

Let's get started!

What is eBPF?

eBPF is a technology that allows you to run small, specialized programs within the Linux kernel. These programs, often referred to as "eBPF programs" or "BPF programs", are triggered by various events occurring within the kernel, such as system calls, network events, or function calls. This capability provides a powerful and efficient mechanism to observe and analyze system behavior in real-time.

eBPF programs are typically written in a restricted C dialect, although other languages like Rust are gaining popularity. The code is then compiled into bytecode and loaded into the kernel using a loader program. Before execution, the kernel meticulously verifies these programs for safety, ensuring that they cannot crash the system or introduce instability.

eBPF represents an evolution of the original Berkeley Packet Filter (BPF), a technology introduced in 1993 to provide a simple way to filter network packets within the kernel. While BPF was limited to network-related tasks, eBPF extends its capabilities to a wide range of use cases, including observability, security, and tracing.

Why Choose eBPF for observability?

eBPF has revolutionized system observability by addressing traditional monitoring challenges while providing unique advantages over other kernel extension methods. Here are the key benefits:

• Efficiency and performance: eBPF programs execute directly within the kernel, minimizing overhead while maximizing performance. Unlike traditional user-space monitoring tools that require context switches and data copying, eBPF programs can directly access kernel data structures, resulting in significant performance gains.

• Dynamic and flexible deployment: eBPF programs can be loaded and unloaded dynamically without kernel recompilation or system reboots. This eliminates the deployment complexity of traditional monitoring agents that often require code changes, recompilation, or application restarts.

• Deep visibility with safety: eBPF provides unparalleled access to system data (including system calls, network packets, and function arguments) while running in a sandboxed environment. The eBPF verifier ensures system stability by rigorously checking programs for safety before execution, preventing issues like infinite loops or memory corruption that could crash the system with traditional kernel modules.

• Developer-friendly: Compared to kernel modules, eBPF programs are typically smaller, easier to write, and more accessible to developers. They don't require the deep understanding of kernel internals needed for kernel module development, yet they provide similar levels of functionality and better safety guarantees.

This combination of features makes eBPF particularly well-suited for modern observability needs, offering a solution that is both powerful and practical for production environments.

Prerequisites

Before you can use eBPF, ensure you have the following prerequisites in place:

• A recent version of Python installed.
• Linux kernel version 4.18 or higher (eBPF features evolve with kernel versions).
• Root or CAP_SYS_ADMIN: Many eBPF tools need elevated privileges to load programs into the kernel.
• Tools: We'll install bpftool, bcc, and others as we go.

Check your kernel version with:

uname -r

6.12.11-200.fc41.x86_64

Setting up your environment

Let's install some foundational tools to interact with eBPF.

Install bpftool

bpftool is a Swiss Army knife for managing eBPF programs and maps.

On Ubuntu/Debian:

sudo apt update
sudo apt install -y linux-tools-common linux-tools-$(uname -r)

On Fedora:

sudo dnf install bpftool

Verify installation:

bpftool version

bpftool v7.5.0
using libbpf v1.5
features: llvm, skeletons

Install BCC (BPF Compiler Collection)

BCC provides Python bindings and tools to write eBPF programs easily.

On Ubuntu:

sudo apt install -y bpfcc-tools

On Fedora:

sudo dnf install -y bcc-tools

Test it:

sudo python3 -c "import bcc; print('BCC installed!')"

You'll also see the tools in /user/share/bcc/tools:

ls -l /usr/share/bcc/tools/

.rwxr-xr-x@   37k root 17 Jul  2024  argdist
.rwxr-xr-x@  2.8k root 17 Jul  2024  commandreadline
.rwxr-xr-x@   16k root 17 Jul  2024  bindsnoop
.rwxr-xr-x@   11k root 17 Jul  2024  biolatency
.rwxr-xr-x@   10k root 17 Jul  2024  biolatpcts
.rwxr-xr-x@  4.0k root 17 Jul  2024  biopattern
.rwxr-xr-x@   11k root 17 Jul  2024  biosnoop
.rwxr-xr-x@  9.6k root 17 Jul  2024  biotop
. . .

Writing your first eBPF program

This section introduces a simple example to demonstrate basic eBPF functionality. The code is:

from bcc import BPF

# Load BPF program
bpf = BPF(text="""
int kprobe__sys_clone(void *ctx) {
    bpf_trace_printk("Hello, World!\\n");
    return 0;
}
""")

# Attach kprobe to sys_clone
bpf.attach_kprobe(event="sys_clone", fn_name="kprobe__sys_clone")

# Print trace messages
bpf.trace_print()

In this snippet, a kprobe is attached to the sys_clone system call which prints "Hello, World!" each time it's called.

To run, save as hello_world.py, ensure BCC is installed, and execute with sudo:

sudo python3 hello_world.py

The output will show "Hello, World!" messages whenever sys_clone is called, typically during process creation, as seen below:

This demonstrates eBPF's ability to run custom code in the kernel when specific events occur. You may quit the process with Ctrl-C before proceeding to the next section

Using eBPF for Observability

eBPF is particularly powerful for observability, enabling the collection of detailed, real-time data from the Linux kernel with minimal overhead, ideal for monitoring system performance, network activity, and application behavior.

Let's write a simple eBPF program to count system calls (e.g., openat) and see the metrics in action.

Create a Python script (syscalls.py):

from bcc import BPF

# eBPF program in C
program = """
#include <uapi/linux/ptrace.h>
BPF_HASH(syscall_count, u64, u64); // Hash map to store counts

int count_syscalls(struct pt_regs *ctx) {
   u64 pid = bpf_get_current_pid_tgid();
   u64 counter = 0;
   u64 *val;

   val = syscall_count.lookup(&pid);
   if (val) {
       counter = *val;
   }
   counter++;
   syscall_count.update(&pid, &counter);
   return 0;
}
"""

# Load the eBPF program
b = BPF(text=program)
b.attach_kprobe(event="sys_openat", fn_name="count_syscalls")

# Print counts every second
print("Counting syscalls... Press Ctrl+C to stop")
while True:
   try:
       for k, v in b["syscall_count"].items():
           print(f"PID {k.value}: {v.value} syscalls")
       b["syscall_count"].clear()  # Reset counts
       sleep(1)
   except KeyboardInterrupt:
       print("Done!")
       exit()

Run it (requires root):

sudo python3 syscalls.py

Generate some syscalls in another terminal:

ls /tmp  # Triggers openat syscalls

You'll see PIDs and their syscall counts updated every second. This is a basic metric collection example!

Next, let's see how eBPF compares with with OpenTelemetry.

Comparing eBPF with OpenTelemetry

Understanding the fundamental differences between OpenTelemetry and eBPF is crucial for implementing effective observability solutions. While both technologies aim to enhance system visibility, they operate in distinct ways and serve different purposes.

Let's look at the main differences below:

1. Stack implementation

OpenTelemetry integrates directly with applications in the user space, providing granular application-level insights. In contrast, eBPF operates at the kernel level, offering deep system-level visibility without requiring application modifications.

2. Performance impact

eBPF's kernel-level operation enables highly efficient data collection with minimal overhead. OpenTelemetry, operating primarily in user space, may introduce slightly more overhead but provides richer application context.

3. Framework structure

OpenTelemetry provides a comprehensive ecosystem of tools, including APIs, SDKs, and collection mechanisms. eBPF, by comparison, is a unified framework embedded within the Linux kernel, offering streamlined functionality.

4. Platform availability

While OpenTelemetry supports all major operating systems, eBPF currently operates exclusively on Linux. However, ongoing development efforts, including Microsoft's Windows port, may expand its availability in the future.

5. Practical implications

When designing observability solutions, organizations often find value in combining both approaches: using OpenTelemetry for detailed application telemetry and eBPF for efficient system-level insights. This complementary strategy provides comprehensive visibility across the entire technology stack.

Note that some emerging tools bridge these technologies, such as OpenTelemetry collectors with eBPF capabilities, offering the best of both worlds for specific use cases.

Integrating eBPF with OpenTelemetry

While OpenTelemetry traditionally operates in user space to gather observability data, an innovative approach combines it with eBPF's kernel-level capabilities. The OpenTelemetry eBPF project enables direct kernel-level data collection while maintaining compatibility with OpenTelemetry's broader ecosystem of observability tools.

This integration offers powerful benefits: you gain eBPF's efficient kernel-level monitoring while retaining the flexibility to export data to any OpenTelemetry-compatible platform. However, it's worth noting that this integration is still maturing. The available collectors support specific use cases rather than providing the comprehensive flexibility of custom eBPF programs.

The OpenTelemetry eBPF ecosystem consists of four key components:

1. Kernel monitoring: The kernel-collector monitors system events at the kernel level, transmitting collected data to a designated remote endpoint configured through environment variables.

2. Kubernetes integration: For container orchestration environments, the k8s-collector specializes in monitoring Kubernetes-specific events, such as pod lifecycle changes, and forwards this data to centralized collection points.

3. Cloud platform monitoring: The cloud-collector interfaces with major cloud providers (currently AWS and GCP), gathering platform-specific observability data to provide insights into cloud resource behavior.

4. Data translation layer: The reducer serves as a critical bridge, transforming raw eBPF data into OpenTelemetry's metric format. This component ensures that data collected through eBPF integrates seamlessly with existing OpenTelemetry workflows and visualization tools.

Despite its current limitations, this integration represents an optimal approach for organizations looking to leverage both technologies' strengths. It particularly suits use cases where kernel-level visibility needs to coexist with standardized observability practices.

How the OpenTelemetry integration works

When you need to gather network observability data at the kernel level while maintaining compatibility with OpenTelemetry-based tools, the kernel-collector component provides a streamlined solution. Here's a comprehensive guide to setting up this integration.

1. Building the components

The first phase involves compiling two essential tools: the kernel-collector and the reducer. Both components use a containerized build process for consistency and simplicity. The build environment can utilize either a custom container or a pre-configured image, with the actual compilation handled by provided build scripts.

You can check the OpenTelemetry-eBPF documentation to find the compilation steps for each component.

2. System deployment

After successful compilation, the deployment process follows a specific sequence:

First, initialize the reducer with your desired output configuration. For example, you can configure it to format data for Prometheus consumption or other OpenTelemetry-compatible formats.

reducer --prom

Next, configure the kernel-collector by setting essential environment variables:

• Specify the reducer's location using EBPF_NET_INTAKE_HOST.
• Define reducer's the communication port with EBPF_NET_INTAKE_PORT.

EBPF_NET_INTAKE_HOST=127.0.0.1

EBPF_NET_INTAKE_PORT=8080

3. Operating the system

Once configured, launch both components to establish the data pipeline:

• The kernel-collector gathers system-level network data through eBPF.
• The reducer transforms this data into OpenTelemetry-compatible formats.
• Your chosen observability platform can then consume the processed data.

The system supports various data export methods, including direct scraping and forwarding to OpenTelemetry collectors via gRPC. This flexibility allows integration with existing observability infrastructures while maintaining the benefits of kernel-level data collection.

The exact configuration options and advanced features are detailed in the project's documentation, allowing for customization based on specific monitoring requirements.

eBPF observability tools to explore

Modern observability requires deep system insights without compromising performance. eBPF-based tools provide this power, and when combined with OpenTelemetry, they offer both depth and standardization. Let's explore five leading solutions, with each one serving different observability needs.

Grafana Beyla

Beyla excels at providing instant visibility into HTTP and gRPC services without code modifications. It automatically captures key metrics like request rates, errors, and durations (RED metrics) using eBPF, while offering seamless export options to both OpenTelemetry and Prometheus.

Beyla's strength lies in its simplicity and lightweight nature. The recent v1.3 release enhanced its OpenTelemetry integration with HTTP context propagation, though its current scope remains focused on HTTP/gRPC protocols.

Odigos

Odigos brings automated distributed tracing to Kubernetes environments, leveraging eBPF to generate detailed traces without requiring application modifications. It seamlessly integrates with OpenTelemetry-compatible systems like Jaeger.

While Odigos requires a Kubernetes environment, it significantly simplifies the tracing setup process compared to manual instrumentation approaches.

Coroot

Coroot provides a holistic view of Kubernetes environments, generating service maps, metrics, and traces through eBPF. Its OpenTelemetry integration enables standardized data export.

Its service mapping capabilities make it particularly valuable for understanding service dependencies and identifying performance bottlenecks within clusters.

Pixie

Pixie automates Kubernetes application monitoring using eBPF, capturing metrics, traces, and dynamic logs. Its OpenTelemetry export capabilities ensure compatibility with existing observability stacks.

Its strength lies in its scriptability through PxL and efficient resource usage, though it's exclusively designed for Kubernetes environments.

Cilium

While primarily known for networking, Cilium provides powerful network-level observability through eBPF. Its Hubble component offers detailed metrics and traces, making it particularly valuable for understanding network behavior.

Each tool serves different observability needs while leveraging eBPF's capabilities. The choice depends on your specific requirements and infrastructure context.

Final thoughts

You've now run eBPF programs to collect metrics, logs, and traces, and explored tools like Beyla, Odigos, Coroot, and Pixie. For deeper learning, explore:

• The official eBPF site with projects and docs.
• Learning eBPF by Liz Rice.
• The OpenTelemetry docs.

eBPF has revolutionized observability in Linux systems, providing powerful capabilities for monitoring, troubleshooting, and optimization.

By understanding and leveraging eBPF, you can gain unprecedented visibility into their systems while maintaining performance and security.

Thanks for reading!

Article by

Ayooluwa Isaiah

Ayo is a technical content manager at Better Stack. His passion is simplifying and communicating complex technical ideas effectively. His work was featured on several esteemed publications including LWN.net, Digital Ocean, and CSS-Tricks. When he's not writing or coding, he loves to travel, bike, and play tennis.

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