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Aviz Fabric Test Automation Suite validates OpenStack VM migration in EVPN-VXLAN

April 21, 2026

Aviz reports on how its Fabric Test Automation Suite (FTAS) validates live VM migration in EVPN-VXLAN environments by checking both control-plane MAC mobility updates and data-plane packet behavior during host handoff. The approach matters for enterprise network and security teams seeking predictable connectivity during compute mobility.

Research Overview

The blog describes a validation method for EVPN-VXLAN fabrics when a VM is migrated between hypervisor hosts using OpenStack live migration. It focuses on the need for rapid network updates across VTEPs so traffic does not continue to forward to an old location.

FTAS is presented as an automated, platform-agnostic framework that validates control-plane correctness and data-plane stability during events such as live migration. The post positions the work as going beyond basic reachability checks.

Key Findings

The validation scenario uses a Leaf-Spine topology with MP-BGP (EVPN) for the control plane and a VXLAN-based Layer 2 overlay. The gateway design is described as a static anycast gateway with the IP 192.168.20.1 and MAC 00:11:22:33:44:55 across all leaf switches.

During migration of a test VM (vm1) from host os02 to os03, FTAS reports only 1.42% transient packet loss during the hypervisor handoff while observing a continuous ping stream from the VM to its gateway. The post also reports that ARP and MAC tables updated to the new physical interface, with no crashes such as orchagent or zebra during the event.

Technical Breakdown

In the described setup, MP-BGP EVPN uses unique ASNs 1001 to 1004 for route exchange, and VLAN 20 is mapped to VNI 100020. The blog also describes that the fabric initialization includes bringing up BGP neighbors and VXLAN interfaces before workloads are introduced.

FTAS validation includes confirming that the fabric learns the VM MAC (fa:16:3e:7f:2e:0a) on the local physical interface before migration. For control-plane integrity, it verifies that the new leaf advertises the VM route with a MAC Mobility (MM) sequence increment of 1, which the blog says triggers immediate forwarding updates across VTEPs.

Operational Impact

The blog frames FTAS results as producing an automated run with no manual intervention, with traffic convergence without blackholing. It describes correct ARP and MAC updates to the new interface and reports system stability during the migration event, including no core dumps.

After the run, it reports automated lifecycle cleanup that removes the test VM and configurations to leave the environment ready for another test. The stated operational expectation is that live migrations can be performed during maintenance or scaling while reducing the need for manual network intervention.

This blog describes how Aviz validated EVPN-VXLAN live VM migration behavior with FTAS by auditing MAC learning and MAC Mobility control-plane updates while measuring data-plane continuity during OpenStack live migration. Blog Signals brief is a fact-based summary of the vendor blog.