Final answer:
In designing an Azure VM infrastructure, a Virtual Network is crucial for providing an isolated environment, and Virtual Machine Scale Sets are beneficial for high availability and auto-scaling. Azure App Service and Azure Container Instances might be used if PaaS or containerization is required.
Step-by-step explanation:
When designing the infrastructure for Azure virtual machines (VMs) as part of a migration from on-premises servers, several key components should be included.
Virtual Network: This is an essential part of Azure infrastructure that provides VMs with an isolated and secure environment to communicate. It includes IP addresses, subnets, and network security groups.
Virtual Machine Scale Sets: While not mandatory for all scenarios, scale sets are useful in providing high availability and auto-scaling for VMs, allowing them to adjust to changing workloads efficiently.
Azure App Service and Azure Container Instances may not be necessary unless the applications being migrated require Platform as a Service (PaaS) capabilities or containerization.
It's important to evaluate the specific needs and workloads of the migrated VMs to determine the right services and configurations for your infrastructure design in Azure.