Virtualization
KVM, libvirt, oVirt, live migration and certificate renewal.
Virtualization articles
Nested Virtualization
Nested virtualization lets a VM run its own VMs. Useful for CI, labs, and running Docker Desktop in a VM — here's how to enable it and what it costs in performance.
October 24, 2026GPU Passthrough with VFIO
Passing a physical GPU to a VM needs IOMMU, a clean IOMMU group, vfio-pci binding, and often a vBIOS. Here's the path and the notorious failure modes.
October 24, 2026Recovering oVirt After Certificates Have Expired
Expired oVirt certs: the engine won't start, hosts go Non Operational, consoles die. Here's the recovery — including the clock-rollback trick when even the tools won't run.
October 24, 2026Renewing oVirt Certificates Before They Expire
oVirt's internal CA and certs have finite lifetimes. Doing the renewal on your schedule — before expiry — is a routine maintenance window, not an incident.
October 24, 2026virtio Drivers Explained
Emulating a real NIC or disk controller is slow. virtio is a paravirtual interface the guest talks to directly — here's what each virtio device does and how to enable it.
October 24, 2026Live Migration Requirements (KVM / libvirt / oVirt)
Live migration moves a running VM between hosts with milliseconds of pause — but only if storage, CPU, machine type, and networking line up. Here's the checklist.
October 24, 2026libvirt Networking: NAT vs Bridged vs Others
The default libvirt network NATs VMs behind the host — fine for a laptop, wrong for a server. Here's each mode and how to put VMs directly on your LAN.
October 24, 2026cloud-init for VM Templates
Build one generic image, then let cloud-init set the hostname, users, SSH keys, packages, and network per instance at first boot. Here's the NoCloud workflow for KVM.
October 24, 2026oVirt Architecture Overview
oVirt is a datacenter virtualization manager on top of KVM. Here's how the engine, VDSM hosts, storage domains, and the hosted-engine model fit together.
September 24, 2026Your First VM with KVM and libvirt
From a bare Linux host to a running VM: the packages, the virt-install command, and the virsh commands you'll use every day.
September 18, 2026qcow2 vs raw, and How Snapshots Work
raw is fastest and simplest; qcow2 gives you thin provisioning, snapshots, and compression. Here's how qcow2's copy-on-write works and how to snapshot a running VM.
September 18, 2026