Category Archives: Ubuntu

Running Proxmox VE inside KVM (nested virtualization)

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Introduction

This will be a shorter post and somewhat of an extension of my last post on building a lab environment in Proxmox VE. Here I’ll explore running Proxmox VE inside of KVM virtual machines using nested virtualization, instead of on bare metal systems. This is useful if you want to experiment with Proxmox VE, but don’t have any extra PCs laying around to run it on. The performance is not as good when compared to running it on physical hardware, but at the same time it has the advantage of being to spin a cluster up and down without having to reinstall the OS on an actual computer. In this post, I will spin up the same Terraform lab environment in Proxmox VE, but with nested virtualization instead of running it on physical hardware. A “bonus” section will involve swapping out Bind and isc-dhcp-server for Dnsmasq in the lab environment.

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Building a lab environment in Proxmox VE with Ansible and Terraform

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Introduction

Recently I started experimenting with Proxmox Virtual Environment, while also evaluating it as a replacement for VMWare ESXi. This post discusses some of my experiences with configuring a Proxmox VE “lab environment” of virtual machines on a separate network segment, using Ansible and Terraform. For me at least, trying this stuff out and blogging about it helps motivate me to learn the stuff and document what I have learned. Like a lot of my posts, this one will delve into different topics and is not meant as a how-to guide (there are better examples of this out there); it is mainly to document what I’ve been working on. I do hope, however, that this provides ideas for someone else and perhaps they can improve on what I’ve done here.

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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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