Azure Resource Manager provides a lot of benefits with support for tagging, RBAC, and infrastructure orchestration using templates. As part of Azure Resource Manager, Virtual Machines gain these new capabilities plus additional compute specific capabilities such as:

• Ability to resize to any VM size without having to delete and recreate the VM
• Ability to migrate to managed disks which provide a simplified management experience while also providing higher availability by leveraging multiple storage controllers for availability sets with multiple instances
• Support for 3 fault domains and 20 update domains

Learn more about Resource Manager and understand the differences between Classic and Resource Manager deployment models.

To allow our customers to benefit from these additional capabilities, we introduced a service that enables customers to bring their classic VMs over into the Resource Manager world without downtime!

Today, we are pleased to announce that customers using ExpressRoute can also migrate their Virtual Networks, including all the VMs in the VNET, to Azure Resource Manager without downtime. Learn more by reading the instructions on how to Migrate ExpressRoute circuits and associated virtual networks from the classic to the Resource Manager deployment model.

There are some edge cases for ExpressRoute migration you should be aware of. Please review the unsupported features and configurations to make sure your environment is supported.

As part of this release, we’re also announcing a revamped documentation set for migration. Based on customer recommendations and migrations, we’ve added additional planning docs and answers for the most frequently asked questions. Existing documents have also been restructured to be easier to understand as part of this effort.

• Overview of platform-supported migration of IaaS resources from classic to Azure Resource Manager
• Technical deep dive on platform-supported migration from classic to Azure Resource Manager
• Planning for migration of IaaS resources from classic to Azure Resource Manager
• Use PowerShell to migrate IaaS resources from classic to Azure Resource Manager
• Use CLI to migrate IaaS resources from classic to Azure Resource Manager
• VPN Gateway classic to Resource Manager migration
• Migrate ExpressRoute circuits and associated virtual networks from the classic to the Resource Manager deployment model
• Community tools for assisting with migration of IaaS resources from classic to Azure Resource Manager
• Review most common migration errors
• Review the most frequently asked questions about migrating IaaS resources from classic to Azure Resource Manager

For a great video overview of the migration process please check out Corey Sanders in the below Microsoft Mechanics episode, Azure Classic to Azure Resource Manager Migration.