Updating the screen resolution in centos7 in Hyper-V

There is a known problem with VMs on Hyper-V unable to set the screen to a high resolution, with no way of changing it either from KDE System Settings or Hyper-V virtual machine properties.

The problem is with the frame buffer driver of Hyper-V. CentOS provides a tool called grubby for managing grub.cfg which is much easier to work with than editing /etc/default/grub and running update-grub.

To set the desired screen resolution under Hyper-V, open a terminal and execute:

sudo grubby --update-kernel=ALL --args="video=hyperv_fb:2560x1440"

then reboot. Replace 2560x1440 with the desired screen resolution.

If you find that you are still unable under Hyper-V to reach the desired resolution, the other solution is to install xrdp and use remote desktop. See the article Install xrdp on CentOS 7 / RHEL 7.