I have worked on the Linux guest on Hyper-V recently, to set a proper screen display is more troublesome than in VirtualBox. (Running Linux on Hyper-V is not a good idea as obviously running slowly, even MS support integration in most Linux kernel to run them. ).
Here is the notes for the CentOS and Ubuntu:
For CentOS and Red Hat
grubby --update-kernel=ALL --args="video=hyperv_fb:1024x768" reboot
Install linux-image-extras (hyperv-drivers):
sudo apt-get install linux-image-extra-virtual
Open the Terminal and type:
sudo gedit /etc/default/grub
Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT, and add
or your preferred resolution in between the quotes (The maximum possible resolution is 1920×1080) like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=hyperv_fb:1920x1080"
Save and Exit.
Restart Hyper-V (restarting Ubuntu (Linux) might be enough.