Redundant VPC VR goes dual PRIMARY (race condition?) #11710
Description
problem
When multiple network tiers are brought up in quick succession in a redundant VPC, I can consistently reproduce both VPCs going primary.
This is really bad because the VIP is then owned by both Virtual Routers and it means traffic is getting dropped like crazy, it makes the entire VPC unusable. Restarting the VPC recovers it to a good state.
Please see the comments for debugging information, but in short it appears at least one of the nodes ends up getting munged address information which causes the wrong ips to be programmed on interfaces and the keepalived configs to diverge between nodes which causes the dual primary. The underlying cause of the issue is this munged address information.
versions
4.21.0
The steps to reproduce the bug
Use Terraform to create the VPC, network tiers, and VM Instances.
Terraform configuration being used is here: https://github.com/bradh352/terraform-config
What to do about it?
No response