SD-WAN link flaps after controlplane update

Products

• VMware
• VMware SD-WAN by VeloCloud

Issue/Introduction

Symptoms:

• Customers may notice WAN link flaps (tunnels going down and back up in quick succession)
• This happens after a SD-WAN edge deployed in a Cluster receives a Control Plane update.
• The physical interfaces are stable.
• Following events are seen repeatedly in the SASE Orchestrator:

Link <Interface name> is now dead
Link <Interface name> is no longer dead
Applied new configuration for deviceSettings version...
Applied new configuration for controlPlane version...

Environment

VMware SD-WAN
VMware SD-WAN by VeloCloud

Cause

This is caused by known issue # 62701.
In a deployment where a Hub Edge site deployed in a Cluster which has Cloud VPN disabled on at least one segment and enabled on other segments, it treats the cluster configuration as disabled while parsing the configuration for the segment with Cloud VPN disabled. As a result, all tunnels from this Hub Edge (towards Spoke Edge sites and VMware SD-WAN Gateways) start flapping

Resolution

This issue has been fixed in version 5.1.0.0 and later.
Both the Orchestrator and SD-WAN Edge must be upgraded to the fixed version. For information on how to upgrade please see VMware SD-WAN Software Upgrade FAQs

Workaround:

To prevent this issue from occurring, please make sure Cloud VPN is turned on for all segments used by the Hub Edge.
Note: only Cloud VPN needs to be turned on, Branch-to-Non SD-WAN Destination via Gateway, Branch to Hubs, and Branch to Branch VPN can remain disabled.

 

Additional Information

Impact/Risks:
The workaround for issue may involve enabling Cloud VPN for the first time. This may cause the edge services to restart, causing a brief interruption of services.
For more information, refer to this article.