When deploying multiple VMs in one Availability Set using an ARM template, you want to ensure the template allows the greatest number of VMs to remain available during maintenance events. What value should you configure for the platformUpdateDomainCount property?

For an Azure Availability Set, the platformUpdateDomainCount property specifies the number of update domains. Update domains are logical groupings of VMs that are updated together during planned maintenance. To maximize the availability of your application during maintenance events, you want to distribute your VMs across as many update domains as possible. The maximum recommended value for platformUpdateDomainCount is 20. While values like 10 are valid, they offer fewer update domains, meaning more VMs could be affected simultaneously during an update. Values like 30 or 40 are not supported and would result in a deployment error. Therefore, 20 provides the optimal balance for high availability within an Availability Set.