Open Source QEMU Alternatives

Windows Sandbox is a virtual machine application that lets you quickly spin up a virtual clean OS imaged from your system's current state so that you can test programs or files in a secure environment that's isolated from your main system.

Vagrant is an open-source software building portable and virtual development environments. With Vagrant, developers and devops can create development environments that mirror production environment by providing the same operating system, packages, users, and configurations. Vagrant can be spin up environments for VirtualBox, KVM, Hyper-V, Docker containers, VMware, and AWS, and integrates with exiting configuration tooling such as Ansible, Chef, Docker, Puppet or Salt

OpenStack is an IaaS (Infrastructure-as-a-Service) and cloud computing platform developed by the OpenStack Foundation. The project was first started in 2010 as a joint venture by Rackspace Hosting and NASA. OpenStack both free and open-source and allows you to create public or private clouds with distributed virtual servers. The OpenStack dashboard can be used by administrators of the cloud to empower user, provision resources and track the overall health of the network and infrastructure.

VirtualBox is a free and open-source hosted hypervisor for x86 virtualization, developed by Oracle. The software is used to create virtual machines that can be used for testing, and building software in virtually contained environments. VirtualBox is available for on macOS, Linux. Windows, Solaris and OpenSolaris.