Which capability lets cloud customers add more VMs behind a load balancer as needed?

Horizontal scaling, also known as scaling out, is the capability that allows cloud customers to add more virtual machines (VMs) or instances to a system to handle increased load. This is often done behind a load balancer to distribute traffic efficiently. Vertical scaling (scaling up) involves increasing the resources (CPU, RAM) of an existing VM, not adding more VMs. Elasticity is the ability of a system to automatically scale resources up or down based on demand, which often utilizes horizontal scaling but is a broader concept. Geo-redundancy refers to replicating data or services across different geographical regions for disaster recovery and high availability, not for adding compute capacity to handle increased load.