구글 클라우드 자원 확장 방안
1) Cloud Monitoring 기반 확장 : https://cloud.google.com/compute/docs/autoscaler/scaling-stackdriver-monitoring-metrics
2) Load Banalcer 기반 확장 : https://cloud.google.com/compute/docs/autoscaler/scaling-load-balancing
3) Latency 기반 확장 : https://cloud.google.com/compute/docs/autoscaler/scaling-stackdriver-monitoring-metrics#example_using_a_utilization_target_to_scale_based_on_average_latency