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Virtual Machine Scale Sets

Azure Virtual Machine Scale Sets offer a robust and flexible solution for deploying, managing, and scaling applications, ensuring high availability and optimal performance to meet varying demands.

Overview

  • Used to create and manage a group of identical, load balanced VMs
  • Traffic will be distributed to the VM instances via a load balancer service
  • VM instances are managed by a single Azure Resource Manager template
  • VM instances can be automatically scaled in or out based on demand or a defined schedule
  • VM instances can be automatically healed if they become unhealthy
  • VM instances can be automatically updated with the latest OS image
  • VM instances can be automatically deployed across multiple fault domains and update domains
  • VM instances can be automatically deployed across multiple regions
  • VM instances can be automatically deployed across multiple availability zones

Use Cases

  • Web front ends
  • API services
  • Batch processing
  • Containers
  • Microservices

Components

  • Scale Set: The group of identical VM instances
  • Load Balancer: Distributes traffic to the VM instances
  • Health Probe: Monitors the health of the VM instances
  • Scale Out: Increases the number of VM instances
  • Scale In: Decreases the number of VM instances
  • Auto Scale: Automatically scales the number of VM instances based on demand or a defined schedule
  • Auto Heal: Automatically heals unhealthy VM instances
  • Auto Update: Automatically updates the OS image of the VM instances
  • Fault Domain: A group of VM instances that share a common power source and network switch
  • Update Domain: A group of VM instances that are updated together

Pricing

  • Pay only for the VM instances that are running
  • No additional charge for the scale set service
  • No additional charge for the load balancer service
  • No additional charge for the health probe service

Scaling

  • Manual Scaling: Increase or decrease the number of VM instances manually
  • Auto Scaling: Automatically increase or decrease the number of VM instances based on demand or a defined schedule