Virtualization Manager displays the operating system of a virtual machine on the VM details page.
In some cases, this information is not available for virtual machines running on a Hyper-V host. This happens when the Hyper-V Daemon is not running on the operating system of the VM. The daemon allows the hypervisor to query the name of the operating system.
all VMAN versions
Install the Hyper-V KVP Daemon.
Hyper-V integration services are a built-in feature of recent versions of Microsoft Windows.
The KVP Daemon is usually available as a package in the standard repositories. For example, on CentOS, the name of the package is 'hypervkvpd'. On Ubuntu, the package name varies between versions. For Ubuntu 14.04, the package is 'linux-cloud-tools-generic'; on older versions, it can be 'linux-tools-generic' or'hv-kvp-daemon-init'.