In Nutanix AHV, when creating a virtual switch and trying to add network interfaces (NICs) to it, the NICs must be connected to the network before they can be selected and assigned to the switch. If the interfaces are showing as disconnected, the system will not allow them to be added to a virtual switch because it cannot verify their operational status or the presence of a live network connection.
It is a standard requirement for the interfaces to have physical connectivity (i.e., network cables plugged in and connected to a live switch port) so that the AHV host can detect the link status as up. Once the interfaces are connected and recognized by the host, they can then be added to a virtual switch in the Nutanix AHV.
It's important to note that while the command-line interface (CLI) is indeed a powerful tool for managing network configurations on AHV hosts, and some configurations do indeed require CLI, the inability to select disconnected interfaces is not specifically a limitation that requires the use of CLI to overcome. The focus should be on ensuring that the physical connectivity is established for the interfaces in question.
This behavior is consistent with networking best practices and Nutanix's network configuration guidelines, as detailed in the Nutanix AHV Networking Guide. This guide explains the requirements and procedures for configuring virtual switches and managing NICs in a Nutanix AHV environment.