I constantly use virtual machines to test scripts, host services, perform deployment tests, etc. I usually use Proxmox in my lab, and Libvirt at work. Recently, I have been deepening my knowledge of public clouds like AWS, GCP, Azure, etc. And if there is one thing that fascinates me, it's how quickly you can create a virtual machine. I sometimes use Cloud-Init to automate the creation of my virtual machines or Packer to create VM templates, but we are talking about a few minutes (not seconds). It was during my research on this topic that I came across Firecracker, an open-source project from AWS that allows you to create microVMs in a few milliseconds (yes, milliseconds). So, I want to be able to create virtual machines in a few milliseconds, but also be able to destroy and recreate them on the fly. As a result, these virtual machines can be used for testing, deployments, services, etc.