You plan to deploy several Azure virtual machines. You need to ensure that the services running on the virtual machines remain available if a single…

To ensure services remain available during a single data center failure, you must distribute virtual machines across physically separate locations.

Availability Zones are physically distinct data centers within the same Azure region, each with independent power, cooling, and networking. Deploying virtual machines across multiple Availability Zones ensures that if one data center fails, the VMs in the other zones continue to operate.

Regions are geographically separate areas, each containing multiple data centers. Deploying virtual machines across two or more regions provides an even higher level of availability, protecting against not only a single data center failure but also a large-scale regional disaster. This solution inherently protects against a single data center outage.

A. Deploy the virtual machines to a scale set.

A scale set is a management tool for identical VMs. By itself, it does not guarantee protection from a data center failure unless specifically configured to span across Availability Zones.

B. Deploy the virtual machines to two or more resource groups.

Resource groups are logical containers for managing and organizing Azure resources. They provide no physical isolation or high availability for the resources they contain.

1. Microsoft Learn, "Describe Azure availability zones": "Availability zones are physically separate datacenters within an Azure region... By designing your solutions to use replicated VMs in zones, you can protect your apps and data from the failure of a single datacenter." This directly supports using Availability Zones (C).

2. Microsoft Learn, "Describe Azure regions, region pairs, and sovereign regions": "A region is a set of datacenters deployed within a latency-defined perimeter... To provide the highest level of resiliency, you can deploy applications across multiple regions by using Azure Traffic Manager." This supports using multiple regions (D) as a solution for resiliency, which includes single data center failures.

3. Microsoft Docs, "Availability options for Azure Virtual Machines": This document outlines the spectrum of availability, stating, "Availability Zones... Protect applications and data from datacenter failures." It also discusses multi-region deployment for disaster recovery, which is a superset of the required protection.

4. Microsoft Docs, "What are virtual machine scale sets?": "To provide high availability to your applications, you can use Availability Zones to automatically distribute VM instances across one or more datacenters." This confirms that a scale set is a mechanism that uses Availability Zones for HA, rather than being the solution itself.