Virtual machine availability requires Microsoft Failover Clustering to be configured - while this can still be considered added complexity (compared to e.g. VMwares integrated  HA) the clustering in Server 2012/R2 has been greatly enhanced, simplified and integrated with VMM:- You can not only add Hyper-V clusters to VMM but also CREATE and MODIFY Hyper-V clusters from within VMM- Availability options for virtual machines on Hyper-V clusters can now be configured using the VMM console, without having to open Failover Cluster Manager (SP1). This includes the ability to configure virtual machine failover prioritization and affinity / anti-affinity rules.- Ability to deploy the VMM server itself as highly available virtual machine- Support for guest clustering (cluster Windows instances in virtual machines) via Fibre Channel (new virtual fibre channel adapter function)There is no restart priority setting for virtual machines or capacity check (if failover capacity is available)New in WS2012 R2 is the ability to detect physical storage failures on storage devices that are not managed by Windows Failover Clustering (SMB 3.0 file shares). Storage failure detection can detect the failure of a virtual machine boot disk or any additional data disks associated with the virtual machine (ensuring that the virtual machine is relocated and restarted on another node - eliminating situations where unmanaged storage failures would not be detected).Also Hyper-V and Windows Failover Clustering are enhanced to detect network connectivity issues for virtual machines. If the physical network assigned to the virtual machine suffers a failure (such as a faulty switch port or network adapter, or a disconnected network cable), the Windows Failover Cluster will move the virtual machine to another node in the cluster to restore network connectivity.

In Windows Server 2016, VM can be protected against network and storage transient issues. If a node has network transient issues, the VM state changes to unmonitored. If the node has for 5mn this kind of issues, the node is placed in quarantine and the VM is moved.

If the cluster has storage issue, the VM state changes to Critial - Paused state. When the storage is recovered, the VM start again from the state before the storage issue.

For more information you can read the following topic: https://blogs.msdn.microsoft.com/clustering/2015/06/03/virtual-machine-compute-resiliency-in-windows-server-2016/