Virtualization

People often think you need VMware, Hyper-V, or at minimum Proxmox to run a “real” hypervisor. Something with a web UI, enterprise features, the whole package. But here’s the thing: KVM with libvirt can do virtually everything those commercial hypervisors do. Live migration, memory ballooning, CPU pinning, GPU passthrough, SR-IOV, nested virtualization — it’s all there. The Linux kernel has been a production-grade hypervisor for over a decade. I run NixOS as my hypervisor. No Proxmox, no web UI, just declarative Nix configs and virsh. Let me show you what’s possible. ...

“So what’s the difference between a container and a virtual machine?” I get this question a lot. And the answer usually involves terms like “hypervisor,” “kernel sharing,” and “hardware abstraction” — which just creates more questions. But there’s actually a deeper question lurking here: what’s the difference between simulation, emulation, virtualization, and containerization? These four concepts are often confused, but they’re fundamentally different approaches to solving the same problem: running something in an environment it wasn’t originally designed for. ...