What must be ensured for the interfaces when configuring an on-premises to Azure failover?

For successful configuration of an on-premises to Azure failover, it is crucial to ensure that both the primary and secondary interfaces are connected to the same virtual network. This is important because having both interfaces within the same virtual network facilitates seamless communication and resource sharing between them. When the failover occurs, the resources should be able to interact without changes to the network configuration or issues arising from being on different networks.

Additionally, being connected to the same virtual network ensures that the necessary access controls and routing can be maintained, thus minimizing downtime and ensuring a smooth transition during failover scenarios. This setup is essential for maintaining network integrity and performance during instance migrations or failovers.

In contrast, connecting interfaces to different virtual networks could lead to additional complexity in route management and could potentially disconnect services, as they wouldn't inherently share the same network addresses or configurations. Thus, ensuring both interfaces share the same virtual network is key to maintaining operational continuity and reliability during failover operations.