Using VM Scale Sets to improve performance and redundancy for hosts
Azure Virtual Machine (VM) Scale Sets let you create and manage a group of load-balanced VMs. VM Scale Sets provide you with redundancy and improved performance for applications that are typically distributed across multiple instances. This enables access to your application through a load balancer that distributes requests to one of the application instances.
If you need to perform maintenance or update an application instance, your customers have access to another available application instance. To keep up with customer demand, increase the number of application instances that run your application.