Quick Emulator, or QEMU, is an open-source machine emulator for Linux environments. QEMU enables system administrators to run multiple operating systems and applications designed for different hardware and software platforms on a single host, such as a PC. QEMU is often used together with KVM. KVM provides hardware virtualization, while QEMU emulates the operating system.
OpenStack uses quotas to limit the resources a tenant consumes and thus prevent system capacities from being exhausted without notification. Fuel has a deployment setting to enable and disable quotas. By default, quotas are disabled.