An administrator is conducting updates in a Nutanix cluster and is being prompted for handling non- migratable VMs. Which VM type is non-migratable?

Virtual machines with attached Volume Groups (VGs) are considered non-migratable. VGs provide block storage to VMs via the iSCSI protocol, with the connection terminating on the local Controller VM (CVM) of the host where the VM resides. During host maintenance or upgrades, a live migration would sever this iSCSI session, leading to data unavailability for the VM. Consequently, the Acropolis Hypervisor (AHV) cannot live-migrate these VMs. The administrator is prompted to take manual action, which typically involves shutting down the VM before the host can enter maintenance mode.

A. VMs without NGT: The absence of Nutanix Guest Tools (NGT) does not prevent a VM from being live-migrated; it only limits access to advanced management features.
B. VMs marked as an Agent: While Agent VMs are also not migrated, this is due to a specific configuration policy. VMs with VGs are non-migratable due to a fundamental technical limitation.
C. Memory Overcommitted VMs: Memory overcommitment is a standard hypervisor resource management feature and does not block the live migration of a virtual machine.

1. Nutanix University, Nutanix Hybrid Cloud Fundamentals Courseware (NHCF 6.5), Module 5: Acropolis Storage Services. The course material explains that Volume Groups provide iSCSI services from the local CVM, a configuration that inherently prevents live migration of the attached VM.

2. Nutanix, AHV Administration Guide v6.5, Section: Volume Group Management > Limitations of Volume Groups. The guide explicitly states, "Live migration of guest VMs that are directly attached to a volume group is not supported."

3. Nutanix, Prism Web Console Guide v6.5, Section: VM Management > Managing a VM (AHV) > Updating a VM. This section details VM configurations and notes that features like direct iSCSI attachment (Volume Groups) impact VM mobility operations such as live migration.

4. Nutanix, AHV Administration Guide v6.5, Section: VM Management > Agent VMs. This document clarifies the behavior of Agent VMs: "AHV does not migrate agent VMs. When you place a host in maintenance mode, agent VMs on that host are powered off..." This confirms they are not migrated but distinguishes them from VMs with technical migration constraints like VGs.