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eBPF Unveiled: Transforming Kernel Operations for Modern Computing

eBPF (extended Berkeley Packet Filter) represents a significant advancement in Linux kernel technology. This blog aims to demystify eBPF, presenting an unbiased exploration of its capabilities, applications, and the way it’s shaping system-level programming. From network optimisation to security improvement, we’ll navigate through the intricacies of eBPF, offering insights into its role in modern computing. Join us as we explore the multifaceted world of eBPF, understanding its impact and potential in the realm of system performance and security.

What is eBPF?

eBPF is a revolutionary technology in the Linux kernel. It allows developers to run sandboxed programs in a restricted virtual machine inside the kernel, without changing kernel source code or adding kernel modules. Initially designed for network packet filtering, eBPF’s capabilities have expanded dramatically, making it a versatile tool in system-level programming.

eBPF provides a high-performance, secure way to dynamically extend kernel capabilities. Its flexibility allows it to be used for a wide range of system-level tasks, revolutionising how monitoring, networking, and security functionalities are implemented within the kernel space. By operating inside the kernel, eBPF programs can efficiently handle high-throughput data, like network packets, making them crucial for performance-critical environments.

What does eBPF stand for?

eBPF stands for “extended Berkeley Packet Filter.” The “extended” signifies its evolution from the original BPF, reflecting its expanded capabilities beyond simple packet filtering. The Berkeley Packet Filter, originally part of the BSD Unix operating system, was designed for network packet capture and filtering. eBPF extends this model with a more robust instruction set, wider applicability, and enhanced performance, transforming it into a powerful tool that can safely and efficiently interact with kernel-level operations.

What is eBPF used for (use cases)?

eBPF has a diverse array of use cases, primarily because of its ability to safely and efficiently extend kernel functionality. Key applications include:

  • Network Functionality: Implementing custom network protocols, packet filtering, and routing without impacting kernel stability.
  • Security: Enhancing system security by dynamically implementing firewalls, access controls, and intrusion detection systems directly within the kernel.
  • Performance Monitoring: Real-time monitoring of system and application performance metrics, enabling detailed observability and troubleshooting.
  • Tracing and Profiling: Kernel and user-space tracing for debugging and performance analysis, offering insights into system behaviour without traditional overheads.
  • Load Balancing: Efficient load balancing in networking scenarios, crucial for high-traffic environments.

These use cases highlight eBPF’s versatility in enhancing, securing, and monitoring system performance at the kernel level.

What are the features of eBPF?

eBPF boasts several powerful features:

  • Safety: eBPF programs are verified for safety within the kernel, ensuring they don’t harm the system (e.g., by preventing infinite loops).
  • Performance: Runs directly inside the kernel, offering high efficiency, especially critical for networking and monitoring tasks.
  • Flexibility: Applicable to a wide range of kernel functions, from networking to security.
  • User-Kernel Space Interaction: Provides a safe interface for user-space applications to interact with kernel-space operations.
  • Event-Driven Programming: Can be attached to various kernel events (like system calls or network events), enabling responsive and dynamic system behaviour.

These features make eBPF a powerful tool for modern kernel-level programming, offering both flexibility and security.

How does eBPF work?

eBPF works by allowing developers to write programs that run within the kernel space, yet in a sandboxed environment. We want to keep things simple, so without taking too much of your time, here’s a quick overview:

  • Writing and Compiling: Developers write eBPF programs, usually in a high-level language like C, which are then compiled into eBPF bytecode.
  • Loading and Verification: The bytecode is loaded into the kernel, where it undergoes a verification process to ensure it’s safe and won’t harm the system.
  • JIT Compilation: Once verified, the kernel performs Just-In-Time compilation of the bytecode to native machine code for efficient execution.
  • Attaching to Kernel Events: eBPF programs are attached to specific kernel events, like network packet arrival or system call execution.
  • Execution: When the specified event occurs, the eBPF program is executed, allowing it to modify, redirect, or inspect the data associated with the event.This process ensures that eBPF programs are both efficient and safe, providing powerful capabilities while safeguarding system integrity.

How are eBPF programs written?

Writing eBPF programs involves a few key steps:

  • Language Choice: Typically, eBPF programs are written in a restricted subset of C for ease of development and readability.
  • Compilation: The C code is compiled into eBPF bytecode using specialised compilers, like Clang/LLVM.
  • Loading into Kernel: The bytecode is loaded into the kernel using eBPF tools like BPF Compiler Collection (BCC).
  • Interaction with User Space: Often, eBPF programs are accompanied by a user-space application for control and data retrieval. This communication is facilitated through maps, which are data structures accessible both to the kernel and user space.
  • Debugging and Testing: Tools like bpftrace and various eBPF front ends assist in debugging and testing eBPF programs.

Writing eBPF programs requires understanding both the capabilities and limitations of the eBPF virtual machine and the kernel APIs it interacts with, making it a unique blend of kernel and application programming.

Which Companies Use eBPF?

A variety of companies across different industries use eBPF for their operations. These companies range from tech giants to innovative startups, each leveraging eBPF’s capabilities in unique ways to enhance performance, security, and efficiency within their systems. The applications vary widely, demonstrating eBPF’s versatility and its growing importance in modern computing infrastructure. Here are a few examples:

Netflix utilises eBPF for detailed network monitoring and performance analysis. They leverage eBPF-based flow logs to gain insights into network traffic patterns, helping them optimise network performance and troubleshoot issues effectively. This approach provides a scalable solution for analysing high volumes of data, enabling Netflix to maintain a robust and efficient streaming service for its users.

Meta (formerly Facebook) uses eBPF in its network load balancer, Katran. Katran leverages eBPF to enhance network performance and scalability. This tool assists in efficiently directing traffic across Meta’s massive network infrastructure, ensuring high availability and reliability of services. By using eBPF, Meta can handle the vast scale of network traffic with improved performance and flexibility.

Walmart, through its L3AF project, use eBPF to enhance network visibility and control within its infrastructure. This approach allows Walmart to manage network policies effectively, ensuring robust security and performance. By leveraging eBPF, Walmart achieves a more dynamic and scalable network operation, crucial for handling their extensive and complex digital environment.

Is eBPF Right for Your Business?

eBPF offers intriguing capabilities for enhancing system performance, security, and monitoring, especially in Linux environments. However, its adoption depends on your business’s specific needs, technical expertise, and infrastructure. While it provides powerful tools for network and system optimisation, it also requires a deep understanding of kernel operations and advanced programming skills. Therefore, it’s vital to consider your organisation’s technical maturity and the complexity of the challenges you face before deciding if eBPF is the right fit for your business.

How can I learn more? 

This article is part of a larger series focusing on the technologies and topics found in the first edition of the TechRadar by Devoteam . To see what our community of tech leaders said about the current position of eBPF in the market, take a look at the most recent edition of the TechRadar by Devoteam.