CentOS

sudo yum upgrade
sudo reboot
sudo echo "SUBSYSTEM==\"memory\", ACTION==\"add\", ATTR{state}=\"online\"" > /etc/udev/rules.d/100-balloon.rules
sudo yum install hyperv-daemons
sudo echo noop > /sys/block/sda/queue/scheduler
sudo systemctl enable hypervkvpd hypervvssd hypervfcopyd
sudo nano /etc/default/grub
GRUB_CMDLINE_LINUX="... elevator=noop"
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
sudo grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
sudo reboot