Creating Virtual Machines with QEMU

Create a Disk Image

Make an OS image with the qcow2 format, which is the native format that QEMU uses to run virtual machines:

qemu-img create -f qcow2 <MACHINE_NAME>.img 10G

Run the Installation

This is for running the installation:

qemu-system-x86_64 -enable-kvm -cdrom <ISO_FILE>.iso -boot menu=on -drive file=image.img -m 2G -cpu host -smp 2 -vga virtio -display gtk,gl=on

Explanation of Options

• -enable-kvm → enables hardware acceleration.
• -cdrom <ISO_FILE>.iso → specifies the ISO image for installation.
• -boot menu=on → enables the boot menu.
• -drive file=image.img → specifies the virtual disk.
• -m 2G → assigns 2 GB of memory.
• -cpu host → passes the host CPU configuration.
• -smp 2 → assigns 2 CPU cores.
• -vga virtio → sets the display adapter (better performance).
• -display gtk,gl=on → uses GTK display with OpenGL enabled.

To enable -vga qxl, load the required modules:

sudo modprobe qxl bochs_drm

I recommend using virtio. You may also choose the display option with:

• -display sdl
• -display gtk

After Installation

Once the ISO installation is complete, remove the option -cdrom <ISO_FILE>.iso:

qemu-system-x86_64 -enable-kvm -boot menu=on -drive file=image.img -m 2G -cpu host -smp 2 -vga virtio -display gtk,gl=on

Useful Shortcuts

• Ctrl + Alt + G → release the mouse pointer to the host machine.
• Ctrl + Alt + F → toggle full screen.