Cross–Layer Telemetry Support in Linux Kernel

This paper introduces Cross-Layer Telemetry (CLT), presents its new version as an improvement and explains how its support is added to the Linux kernel. CLT is a way to combine in-band telemetry and Application Performance Management (APM, based on distributed tracing with OpenTelemetry) into a single monitoring tool providing a full network stack observability. Using CLT, APM traces are correlated with corresponding network traffic, providing a better view and a faster root cause analysis in case of issue. This new version improves the correlation accuracy. In this paper, we describe the CLT implementation (both for kernel and user spaces) and we evaluate the CLT ecosystem based on a use case. All CLT code is available as open source.