qemu

Open-source machine emulator and virtualizer

TLDR

Run virtual machine

$ qemu-system-x86_64 -hda [disk.img]

Run with memory

$ qemu-system-x86_64 -m [2048] -hda [disk.img]

Boot from ISO

$ qemu-system-x86_64 -cdrom [installer.iso] -boot d

Enable KVM acceleration

$ qemu-system-x86_64 -enable-kvm -hda [disk.img]

Network with port forwarding

$ qemu-system-x86_64 -hda [disk.img] -netdev user,id=net0,hostfwd=tcp::2222-:22 -device e1000,netdev=net0

QEMU (Quick EMUlator) is an open-source machine emulator and virtualizer that can run operating systems for any supported architecture on any host. It provides full system emulation including CPU, memory, storage, and peripheral devices, supporting architectures like x86, ARM, RISC-V, MIPS, PowerPC, and others.When combined with KVM (Kernel-based Virtual Machine) on Linux, QEMU achieves near-native performance by using hardware virtualization extensions. Without KVM, it uses dynamic binary translation for full software emulation, which is slower but works across platforms. QEMU disk images support multiple formats (qcow2, raw, vmdk) with features like snapshots, thin provisioning, and backing files.

PARAMETERS

-hda FILE

Primary hard disk.

-m SIZE

Memory in MB.

-cdrom FILE

CD-ROM image.

-enable-kvm

KVM acceleration.

-boot ORDER

Boot order.

-smp CPUS

CPU count.

INSTALL

sudo dnf install qemu

sudo zypper install qemu

brew install qemu

nix profile install nixpkgs#qemu

CAVEATS

Performance varies by mode. KVM for best performance.

HISTORY

QEMU was created by Fabrice Bellard for processor emulation.