Network & Infrastructure / High Availability & Recovery Design
VRRP tracking that detects upstream loss rather than link carrier
A router remains the active gateway after its upstream service fails because its LAN interface is still up. Basic link tracking does not cover the full availability dependency.
Environment and inputs: Routed and clustered services; define failure ownership, fencing and application recovery requirements before testing. Diagnostic/design example; not tested on production equipment.
Collect the evidence
Map the service's upstream routes, next-hop reachability and tracking targets. Determine whether the probe can succeed through an unintended backup or through the gateway role it controls.
Explain the result
Gateway election can remain stable while useful forwarding is lost. A poorly chosen probe can also create feedback, with failover causing the very condition that changes priority again.
Plan the fix
Design supported priority tracking around independent, meaningful dependencies and bounded hysteresis. Avoid using one remote endpoint as an unquestioned representation of all upstream availability.
Check the result and rollback
Test upstream failure, probe-target failure and recovery separately while watching role churn. Restore the previous tracking policy if it flaps or transfers ownership to a less capable path.