Service load balancing policies (serviceLbPolicy) are now supported for regional external Application Load Balancers...

Service load balancing policies (serviceLbPolicy) are now supported for regional external Application Load Balancers and regional internal Application Load Balancers. This feature enables advanced load balancing optimizations such as custom load balancing algorithms, auto-capacity draining, failover thresholds, and the ability to designate preferred backends for these load balancers.

For more information, see Advanced load balancing optimizations.

This feature is in Preview.