VNetPath: Diagnosis of Virtual Network Failures in Virtualized Environments through Path Tracing

Long Wang

Abstract:

Virtualized environments are the foundation of mod-
ern computing, but their complex and dynamic virtual net-
works make failure diagnosis challenging. First, failures are often
triggered by specific network flows, but generic probes cannot
replicate these flows to reproduce and diagnose the fault. Second,
existing diagnostic tools lack the required granularity, operating at
the device or IP level and thus missing faults that occur at the level
of network device ports (not the port concept in TCP or UDP). To
fill the gap, we propose and implement VNetPath, an approach
that directly diagnoses failures by replaying the network context
of a failed request and constructing its end-to-end paths, operating
at the granularity of network device ports with eBPF-based non-
intrusive tracing. We conducted experiments by selecting typical
network fault types from a real-world cloud system, designing
fault injection methods, and injecting 6942 faults to a testbed
cloud. Our experimental results show that VNetPath achieves a
diagnosis accuracy of 93.45% on injected faults, demonstrating its
ability to pinpoint failures that are invisible to telemetry systems
like Zoonet (73.27%) and Traceroute (18.22%), while incurring a
low standing overhead of only 0.81%.