What must an administrator do before disabling the Network Controller?

The Network Controller is the core component that enables and manages the Virtual Private Cloud (VPC) infrastructure within Nutanix Flow Virtual Networking. Disabling the Network Controller is a destructive operation that removes this entire software-defined network overlay. Before the system allows this action, all dependent resources that the Network Controller manages must be removed. This includes all virtual machines connected to VPC subnets, the subnets themselves, and finally, the VPCs. This ensures a clean removal of the networking stack without leaving orphaned or non-functional network configurations.

A. Migrate all VMs to a different cluster: This is incorrect. VMs must be removed from the VPC subnets, but migrating them to another cluster is not a mandatory prerequisite for disabling the local Network Controller.
B. Disable Flow Microsegmentation: This is incorrect. Flow Microsegmentation (for security policies) and Flow Virtual Networking (for VPCs) are distinct features. Disabling one does not require disabling the other.
C. Place the CVMs in maintenance mode: This is incorrect. Controller VM (CVM) maintenance mode is used for node-specific hardware or software maintenance and is unrelated to disabling a cluster-wide virtual networking feature.

1. Nutanix Flow Virtual Networking Guide v4.0: In the section "Disabling Flow Virtual Networking," the guide explicitly states the prerequisite: "You can disable Flow Virtual Networking only after you delete all the VPCs and subnets." It then lists the required steps in order: 1. Delete all the VMs that are connected to the VPC subnets. 2. Delete all the subnets. 3. Delete all the VPCs. 4. Disable Flow Virtual Networking. (Reference: Nutanix Portal > Documentation > Software Documentation > Flow Virtual Networking)