An Ultimate Guide to eBPF for better Observability

Extended Berkeley Packet Filter, or eBPF, is an advanced method to execute small bespoke programs inside the Linux kernel. Acting like a virtual machine, eBPF programs load at runtime, enabling real-time analysis of system events such as network activity and function calls.

With its low overhead and adaptability, eBPF provides insights into the kernel's inner workings and facilitates efficient observability and security measures without necessitating kernel modifications. eBPF serves as an effective tool to enhance the operation and performance of Linux systems.

This article explores the basics of eBPF, as well as the current challenges in monitoring and collecting observability data points. It will focus on how eBPF assists with network and security observation, provide relevant use cases, and discuss the benefits and potential drawbacks of eBPF.

What is eBPF?

From a networking standpoint, eBPF is commonly used for packet filtering and processing. Consequently, it can be attached to networking hooks, allowing users to analyze and filter network packets at various stages of the networking stack. This is valuable for implementing custom firewall rules, monitoring network traffic, and dynamically tracing kernel functions, system calls, and user-space applications.

eBPF allows developers and system administrators to trace the execution flow, inspect variables, and gather performance data, circumventing the need for traditional debuggers.

Furthermore, eBPF profiles the performance of various kernel functions and user-space applications, providing insights into resource utilization and bottlenecks. It also enables the creation of security monitoring tools by allowing the observation of system events and behaviors. Hence, it proves handy in detecting anomalies, tracking security-relevant activities, and responding to security incidents.

Most importantly, eBPF is designed to run safely with restrictions that prevent it from causing issues or crashing the system. Its role in the Linux kernel is diverse, spanning networking, security, and observability; this makes it a powerful tool for developers, administrators, and security professionals working with Linux systems.

Challenges with monitoring HTTP sessions

Effective monitoring of HTTP sessions is essential for maintaining the integrity and functionality of web services while safeguarding against potential risks and disruptions.

However, there are a few challenges in monitoring HTTP sessions:

• Traditional monitoring tools can introduce significant performance overhead, impacting the performance of the system being monitored.
• The widespread use of HTTPS encrypts the content of HTTP sessions, making it difficult to inspect data for monitoring purposes.
• Users frequently switch between devices, making it challenging to maintain a consistent session across different platforms. Determining the appropriate session timeout and handling user inactivity is crucial for efficient session management.
• Detecting and responding to security threats within HTTP sessions requires real-time and detailed monitoring.

eBPF can address several of these challenges associated with monitoring HTTP sessions by providing a flexible, low-overhead, and dynamic framework for capturing and analyzing network events at the kernel level. Its capabilities contribute to efficient and real-time monitoring in dynamic and encrypted environments.

Collecting observability data with eBPF

eBPF allows users to leverage observability by collecting and analyzing a wide range of data within the Linux kernel. Organizations can use this data to gain insights into system behavior, troubleshoot performance issues, and monitor various aspects of the system.

eBPF programs can even collect custom metrics by aggregating and analyzing data within the kernel, providing a tailored view of system behavior, including application-specific metrics, user-defined KPIs, and other insights relevant to the environment.

Attaching eBPF programs to relevant points lets them collect data on execution times and resource utilization. This, in turn, helps to identify resource-intensive functions, measure the impact of any changes made, and optimize system performance.

Additionally, eBPF can trace and log error conditions to help organizations understand the causes of failures. Detecting errors and failures in real time allows for proactive issue resolution, reducing downtime and improving system reliability.

Lastly, eBPF supports the tracking of user-level applications, providing insights into user-space behavior. Understanding user-level interactions, system calls, and application-specific events enhances observability at the application layer.

Leveraging eBPF for observability provides real-time insights, facilitates troubleshooting, and enables the creation of customized monitoring solutions tailored to specific use cases and environments.

Network observability

Leveraging eBPF for network observability involves writing eBPF programs that can be attached to various networking hooks within the Linux kernel. These programs can then offer key data on network behavior by analyzing network traffic.

eBPF use cases for network observability

Organizations can adopt eBPF in the following ways to improve network observability:

• Traffic analysis: Capture and analyze packet-level data, including headers and payloads; this helps understand communication patterns, identify anomalies, and troubleshoot network issues.
• Latency monitoring: Measure and analyze the latency of network connections by tracing the time taken for packets to traverse the network stack; this is crucial for identifying performance bottlenecks.
• Protocol analysis: Analyze network protocols by capturing and inspecting packets at various protocol layers; this is useful for debugging protocol-specific issues and understanding the behavior of different applications.
• Connection tracking: Implement connection tracking to monitor established connections; this allows you to track connection states and gather statistics on connection-related events.
• Distributed tracing: Trace requests as they travel across a distributed system; this can shed light on how requests and answers move across various services.

eBPF tools and libraries for network observability

There are several solutions on the market today that enable organizations to leverage eBPF for enhanced network observability. Below are a few top tools:

• bpftrace: An advanced eBPF tracing language and runtime; writes scripts to trace various events, including networking events
• tc (Traffic Control): A command in Linux for attaching eBPF programs to networking hooks for traffic control purposes, allowing for advanced packet processing
• Cilium: An open-source eBPF-based networking and security project for containerized applications; offers observability, security, and network connections
• Weave Scope: An eBPF-powered visualization and monitoring tool for Docker and Kubernetes that gathers network-related information

Using these tools and examples, organizations can use eBPF to gain deep insights into their network's behavior, troubleshoot issues, and monitor various aspects of network performance and security.

Security observability

Organizations can leverage eBPF’s capabilities to monitor and analyze security-relevant events within the Linux kernel. eBPF can be applied to various security use cases, and its integration with security information and event management (SIEM) platforms boosts security incident detection and response.

We can also write relevant eBPF programs to specific security-related hooks, such as tracepoints for system calls, networking hooks, or other points where security events can be captured.

eBPF use cases for security observability

Many scenarios exist in which organizations can implement eBPF to improve insights into their security posture:

• System call monitoring: Trace and monitor system calls, tracking the behavior of applications and identifying potentially malicious activities.
• Network security: Keep an eye on network activity, detect irregularities, and spot any security risks or unauthorized access.
• Security audit logging: Implement detailed audit logs for security-relevant events, providing a trail of activities for forensic analysis.
• Intrusion detection: Identify patterns typical of intrusion attempts, e.g., suspicious network behavior and multiple failed login attempts.
• Container security: Implement security observability for containerized environments by monitoring container activities, network traffic, and interactions.

Tools and libraries for eBPF security observability

With the variety of tools and frameworks available on the market, we list the most popular open-source solutions, along with a quick summary for deploying eBPF programs for security observability:

• bpftrace: High-level tracing language and runtime for eBPF; allows for writing scripts to trace various security events
• BPF Compiler Collection (BCC): Collection of tools and libraries for eBPF development; contains tools for creating, loading, and tracking eBPF programs, as well as use cases pertaining to security
• bpftool: Command-line tool for loading and managing eBPF programs; provides functionality to interact with an eBPF virtual machine and helps manage security-related eBPF programs
• Cilium: Open-source eBPF-based networking and security project for containerized applications; networking, security, and visibility logic provided via eBPF bytecodes inserted into the Linux kernel at several locations, e.g., network IO, application sockets, and tracepoints

There are multiple ways of integrating eBPF observability data points with an SIEM platform. You can configure eBPF programs to log security-relevant data in a format compatible with your SIEM platform. Or, you can use logging agents or connectors to forward eBPF-generated logs to a centralized logging server that integrates with your SIEM solution.

Additionally, organizations can develop custom scripts or integration mechanisms to transform and forward eBPF-generated data to the SIEM platform. Note: This may involve using standardized log formats and protocols.

Advantages of eBPF

There are a few key advantages for organizations that implement eBPF.

Efficient observability

eBPF allows for efficient and dynamic observability within the Linux kernel, enabling the collection of detailed insights into system behavior without significant performance overhead.

Real-time tracing

eBPF facilitates real-time tracing of various events, providing timely insights into system activities.

Customizable monitoring

eBPF allows for the creation of highly customizable monitoring solutions. By writing eBPF programs tailored to specific use cases, organizations can gather precisely the data they need for observability.

Dynamic loading and unloading

Also, it is possible to dynamically load and unload eBPF applications into the kernel without having to restart the system. This allows you to provide some on-demand additions or removals.

Disadvantages of eBPF

Although eBPF is a powerful and flexible technology, it also has its disadvantages and challenges. We list a few of these potential drawbacks.

Learning curve

Developing eBPF programs requires a good understanding of the Linux kernel, networking, and the eBPF framework. For those unfamiliar with these technologies, there will be a learning curve.

Kernel compatibility

eBPF's functionality may be limited by the version of the Linux kernel in use. Compatibility issues may arise if the kernel version is outdated or lacks support for specific eBPF features.

Security concerns

While eBPF is designed to be safe, writing complex or insecure eBPF programs could potentially impact system stability and security. Developers should take the utmost care in following best practices while developing and deploying eBPF codes on the kernel to avoid exposing themselves to any vulnerabilities that could hamper the entire system.

Limited visibility in user space

eBPF primarily provides visibility into the kernel and networking stack. Monitoring user-space applications may require additional tools, and certain events might not be fully observable from within the kernel.

eBPF vs. traditional methods

When compared to traditional monitoring systems, eBPF's efficiency allows for continuous monitoring without negatively impacting system performance. This greater flexibility allows for the creation of tailored monitoring solutions, adapting to specific use cases and requirements. eBPF also excels in real-time tracing and monitoring, providing instantaneous insights into system events.

Conclusion

Observability tools are vital in modern computing, offering crucial insights into complex system performance, health, and behavior. With the increasing distribution and dynamism of systems, traditional monitoring tools can fall short when it comes to capturing intricate interactions.

Enter eBPF, a kernel-level powerhouse providing deep visibility and control. Its dynamic code insertion allows real-time monitoring and analysis of system events without modifying the kernel. In essence, eBPF addresses challenges in gathering and monitoring observability data, excelling in network and security observation. However, organizations should note that along with advantages, its implementation brings potential disadvantages as well.