This article will show how to use Apache SkyWalking with eBPF to make network troubleshooting easier in a service mesh environment.
Apache SkyWalking is an application performance monitor tool for distributed systems. It observes metrics, logs, traces, and events in the service mesh environment and uses that data to generate a dependency graph of your pods and services. This dependency graph can provide quick insights into your system, especially when there’s an issue.
However, when troubleshooting network issues in SkyWalking’s service topology, it is not always easy to pinpoint where the error actually is. There are two reasons for the difficulty:
- Traffic through the Envoy sidecar is not easy to observe. Data from Envoy’s Access Log Service (ALS) shows traffic between services (sidecar-to-sidecar), but not metrics on communication between the Envoy sidecar and the service it proxies. Without that information, it is more difficult to understand the impact of the sidecar.
- There is a lack of data from transport layer (OSI Layer 4) communication. Since services generally use application layer (OSI Layer 7) protocols such as HTTP, observability data is generally restricted to application layer communication. However, the root cause may actually be in the transport layer, which is typically opaque to observability tools.
Access to metrics from Envoy-to-service and transport layer communication can make it easier to diagnose service issues. To this end, SkyWalking needs to collect and analyze transport layer metrics between processes inside Kubernetes pods—a task well suited to eBPF. We investigated using eBPF for this purpose and present our results and a demo below.