Question

You operate a regional internal passthrough Network Load Balancer fronting a backend service with two managed instance groups acting as primary and failover backends. Your team requires that traffic fail over to the backup group when fewer than 60% of the primary instances are healthy, and that traffic automatically fall back once the primary recovers. Which configuration on the backend service achieves this requirement?

Accepted Answer

Set the failover ratio to 0.6 on the backend service and mark the second instance group as a failover backend, leaving 'drop traffic when all backends are unhealthy' at its default.

Answer

Configure connection draining with a 60-second timeout so connections shift to the backup group when the primary degrades.

Answer

Set session affinity to CLIENT_IP and rely on the health check interval to redistribute traffic to the backup group.

Answer

Enable global access on the forwarding rule so clients in other regions reach the failover instance group when the primary is at 60% health.