I have built OVMF and GRUB2 from source and also able to load the kernel image, but having difficulty creating a rootfs disk image and attaching it to qemu so that kernel detects it. ZVHD and ZVHD2 are self-developed image file formats and cannot be identified by qemu-img.To convert image files to any of the two formats, use the qemu-img-hw tool. If you want to have a persistent VM, you need to create an overlay storage image in qcow2 format. qemu-img supports the mutual conversion of image formats VHD, VMDK, QCOW2, RAW, VHDX, QCOW, VDI, and QED. Start from an Ubuntu Cloud image: modify an existing disk image to suit your needs without using autoinstall. There are two main ways to build Ubuntu 20.04 qemu images: Start from an installation ISO: do a true hands-free automated installation with autoinstall. You can add an M suffix to give the size in megabytes and a G suffix for gigabytes. where myimage.img is the disk image filename and mysize is its size in kilobytes. I am simulating the combination of UEFI + GRUB + Kernel. By default, QEMU will run your image in snapshot mode, discarding any changes you made to the disk image as soon as it exits. Packer has official support for Qemu builders. You can create a disk image with the command: qemu-img create myimage.img mysize. create - This tells qemu-img that we are creating a disk image. It is necessary for using the following command. Disk image format is related with the host system. Use it to have smaller images (useful if your filesystem does not supports holes, for example on Windows), zlib based compression and support of multiple VM snapshots. Disk image format is different than file systems. QEMU image format, the most versatile format. As stated before qemu supports different type of disk image formats. It will create an output similar to this: The command is broken down like this: qemu-img - This is the name of the program. Disk image actual size is 0 because there is no data in it but the vm will see disk image as 10G disk and will be able to use up to 10G. qemu-img create -f qcow2 example.img 100M. I am able to launch the linux kernel on QEMU using -kernel and that's pretty straight-forward and simple.īut now I am attempting something different. The standard command for creating a basic hard disk image is this.