CloudStack’s classic KVM guest networking story is “one Linux bridge or OVS bridge per VLAN, per host”. That works, but it doesn’t scale well once you want overlay networks, distributed routing, or anything resembling a modern SDN control plane. OVN (Open Virtual Network) gives you that control plane on top of Open vSwitch: a central Northbound/Southbound database pair plus ovn-controller agents on every hypervisor, all talking Geneve to each other.

This post walks through wiring a small CloudStack KVM setup up to OVN: one dedicated controller node, a handful of Ubuntu KVM hosts, and the small CloudStack-side changes needed to make the Guest network actually land on OVN’s integration bridge instead of a plain OVS bridge.

MySQL and PostgreSQL are two of the most popular open-source relational databases. They share SQL foundations but differ in philosophy, features, and typical use-cases. Below is a concise comparison followed by a handy table of equivalent, commonly-used commands.

This post documents the process of creating a new GPG key, backing up a GPG key, importing it to a new machine, and editing the user ID (UID) associated with the key. This is useful for administrators who need to migrate GPG keys, update key metadata, or generate new keys for secure communication.

This post documents the process of backing up a GPG key, importing it to a new machine, and editing the user ID (UID) associated with the key. This is useful for administrators who need to migrate GPG keys or update key metadata.

This post explains a small libvirt patch that adds qcow2 (and other qemu image formats) support when creating volumes on logical (CLVM) storage pools. The patch lets libvirt use qemu-img to initialise a LV as a qcow2 image and then expose that LV to a VM as a block source while preserving activation locking behavior for clustered LVM setups.

This post documents how to fetch, patch and rebuild libvirt (libvirt 10.0.0) on Ubuntu 24.04. The instructions show how to obtain the original source (Launchpad / Ubuntu archives), install build dependencies, apply local patches, and produce installable .deb packages.

The upstream Ubuntu libvirt source and recent packaging patches are available on Launchpad: https://launchpad.net/ubuntu/+source/libvirt