Availability Options for Virtual Machines in Azure

• High Availability in Azure is majorly provided by following basic constructs

  • Availability Zones:
    • Some Regions of Azure support Availability zones
    • If you are deploying vm’s on these regions then it is recommended to use Zone resilient deployment
  • Availability Set:
    • Each availability Set will have Fault domains & update domains
    • Fault domain is logical group of underlying hardware which share a common power source & network switch within a data center (rack)
    • Update domain is a logical group of underlying hardware that can undergo maintenance or be rebooted at the same time without impacting application.

• Best Practices for Virtual Machines

  • Avoid running a production workload on a single vm: Instead put VM in availability set or virtual machine scale set, with a load balancer in front
  • Put each application into a separate Availability Set
  • Replicate VMs using Site Recovery
  • Use Azure Backup to backup vms
  • Enable logging & monitoring

Virtual Machine Scale Sets:

• Consider your organization is hosting an application which is used for ticketing
• Now users have increased drastically
• Now how can we ensure our application still works without performance problems?
• Increasing servers will be an option
• Our application is ticketing application so it will have peak and non peak hours
• So we need to increase or decrease the servers based on demand. Now will it be better to do this manually or if azure handles it and you provide inputs to azure?
• The Azure’s way of handling these kind of scenarios is Azure Virtual machine scale sets(VMSS)