Microsoft Certified: Azure Administrator AssociateDeploy and manage Azure compute resourcesMedium
A company is deploying several Azure Virtual Machines (VMs) that will host a critical application. The application requires high availability and resilience to hardware failures within an Azure region. The VMs must be distributed across different physical hardware, fault domains, and update domains within the same datacenter to minimize downtime during planned or unplanned maintenance. Which Azure feature should be used to meet these requirements?
- AAzure Virtual Machine Scale Sets (VMSS)
- BAzure Availability Sets
- CAzure Availability Zones
- DAzure Site Recovery
Show answer & explanationAnswer & explanation
Correct answer: B. Azure Availability Sets
Azure Availability Sets distribute VMs across different fault domains and update domains within a single data center, ensuring that a single point of failure (like a rack or host update) does not take down all VMs in the set.
Why the other options are wrong
- A. VMSS is for scaling out VMs and can use Availability Zones or Sets, but it's a scaling feature, not the primary feature for distributing VMs across fault/update domains within a datacenter.
- C. Availability Zones provide resilience across physically separate datacenters within a region, which is a higher level of isolation than requested (within the same datacenter).
- D. Azure Site Recovery is for disaster recovery across regions or from on-premises to Azure, not for ensuring high availability within a single datacenter.
Azure Availability Sets
A logical grouping capability for isolating VM resources from each other when they're deployed. It ensures that VMs are distributed across different physical hardware in a datacenter.
- Protects against unplanned hardware failures
- Protects against planned maintenance
- Distributes VMs across Fault Domains (up to 3)
- Distributes VMs across Update Domains (up to 20)
- Operates within a single Azure datacenter
Memory trick: Availability Sets Keep VMs Safe in the Same House.