Category Archives: Ubuntu

Modifying my Perl YAML-based Provisioner for KVM

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Introduction

In my last post, I discussed how I wrote a Perl script that uses a YAML file to build a list of virtual machines on the Xen hypervisor. When the script was nearly complete, it occurred to me: why not modify this script for use with libvirt/KVM? I mainly use KVM instead of Xen because of its better support for Enterprise Linux. Often, when I need to spin up a set of virtual machines for testing, I use dmacvicar/libvirt provider for Terraform. Usually this works pretty well; however, sometimes I get annoyed at having to learn the HCL language and just want to define a list of VMs with my specs. That is where I can see this script being of use, at least for myself. Of course, my intention was not to replace Terraform, even for myself. Mainly, this was a fun project that exercised my Perl skills and taught me stuff about Linux networking, libvirt, and more.

KVM host setup

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Writing a Perl YAML-based Xen Provisioner

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Introduction

In my previous post on the Xen hypervisor, I mentioned my interest in writing a Perl provisioning tool for Xen that functions similarly to Terraform. This tool isn’t meant to replace Terraform (nor claim that it is superior), but there doesn’t seem to be a Terraform provisioner for standalone Xen. Furthermore, sometimes it makes more sense to code a custom tool that does exactly what you want, versus trying to adapt an existing tool, especially a complicated one like Terraform. This tool has a single purpose: to give the user the ability to define a set of virtual machines with their specs (RAM, disk space, static IP addresses, etc.) and spin up these VMs with a single command, as well as take them down when they are no longer needed.

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Configuring Ubuntu and Debian as a router

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Recently, for my home network, I transitioned from using a standard home router running DD-WRT to a setup with a separate managed switch, wireless access point, and a combination router/server running Ubuntu 24.04. The “router” is a basic x86-64 mini-PC with two network interfaces, purchased for about $100. The internal interface hosts three VLANs (internal, lab, and guest) and provides DHCP, DNS, and LDAP services. I prefer this setup to something like OPNsense, because I can manage everything with the command line and Ansible. If the cheap PC dies an early death or I want to switch to something newer, I can simply install Ubuntu on the replacement system, configure the NICs, and run the Ansible project to configure everything else. It also gives me a low-power-usage PC that I can run other services on in containers or even virtual machines. In this blog post I run through the steps for configuring a router like this, with both Ubuntu and Debian.

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