Building a Perl DBD::Oracle Apache Docker container

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Introduction

In my last post, I discussed building RPM packages for the Perl Oracle DB driver for Enterprise Linux. These packages were then used to build a Docker container running Apache and an Oracle client, which could be used to serve Perl CGI scripts. In this post I discuss installing this same module, but in a Debian-based Apache/HTTPD container, which is more lightweight and better-suited to running Apache than a full OS container. For me, this was a quick way to get a 90s-style Apache CGI environment up and running in order to start learning how to do some basic web development for systems administration (full disclosure: I am not a web developer).

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Building Perl DBD::Oracle RPM packages for Enterprise Linux

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Introduction

One of the many “hats” I wear in my job is an Oracle database administrator. In this role I write a number of Perl scripts that interact with the Oracle DB, and are used for purposes such as updating data and automating maintenance tasks. Over the years I’ve built up a fairly large library of scripts that I can clone off of when I need something new. With Perl and Oracle, one uses the DBI module for Oracle, DBD::Oracle. I’ve mostly used this on Red Hat systems—Enterprise Linux or EL, as I will refer to it here—distributed with an RPM package (instead of being installed using CPAN). Perhaps because it requires the installation of closed-source Oracle software, there aren’t pre-built RPMs of DBD::Oracle; I’ve always had to build these myself, using an RPM spec file I inherited from a colleague. However, I’ve wanted to revisit this and find a spec file from a source outside of work, one that I could use for experimentation in personal projects, as well as providing an improved version for my work. I was able to find a spec file from a public source, make some improvements, and build the packages for Enterprise Linux versions 7 through 10. This post documents those steps.

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Automated UEFI Network Installation of Debian with GRUB2 and Preseed

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Introduction

For a number of years, I’ve performed numerous Linux network installations on “legacy” BIOS systems with TFTP and PXELinux. This has been convenient when I’ve needed to build a lot servers, and has worked well when paired with Preseed automated installations on Debian systems or Kickstart automated installations on Enterprise Linux systems. However, BIOS has largely been superseded by UEFI; for better or worse, all computers now ship with UEFI firmware. It is also the default firmware mode on VMWare ESXi. With UEFI, PXELinux no longer works; now you must use GRUB2 over PXE. Recently I decided I wanted to learn how to do this with Debian, as I needed to install Debian 13/Trixie on four identical HPE ProLiant servers running UEFI firmware and wanted to do automated Preseed installations, as opposed to installing the OS manually on each server. This post explains how I was able to get this to work.

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Adding libvirt networking to my Perl YAML-based KVM Provisioner

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Introduction

Hello World! It has been a few months since I’ve posted anything here, due to taking on a new role at work and having to learn new skills for it.

In a previous post, I described writing a Perl provisioning script for creating KVM virtual machines. The list of machines and attributes are defined in a YAML file, and then “spun up” using virt-install and cloud-init. It performs a similar role to Terraform, but is simpler and more focused. Mainly I wrote it to improve my Perl skills and learn more about libvirt, not replace Terraform entirely.

However, I later realized that the usefulness of this script is diminished by the fact that it can’t create libvirt NAT networks or provision virtual machines with static IP addresses. My first version used Dnsmasq for assigning addresses to the VMs; I’ve now soured on this approach. Instead, I’ve decided to re-factor this script to use cloud-init to assign a static IP address to the VM. This post will talk about the rewrite of the script.

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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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Installing Debian 12 and 13 on a ProLiant DL360 G7

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Introduction

In a previous post, I discussed my experiences with installing a recent version of Enterprise Linux, AlmaLinux 9, on an e-waste HP ProLiant DL360 G7. I also discussed updating the firmware for the Integrated Lights-Out (iLO) remote management tool and the HP Smart Array controller, and installing the OS over the network from the iLO console. In this post I will perform some of these tasks, but for Debian instead. I will also incorporate some knowledge from my previous posts on virtualization, networking, and Ansible.

These exercises were performed on a ProLiant DL360 G7, but it’s likely that they will work on other Proliant servers.

A ProLiant DL360 G7 at the bottom of an e-waste stack.

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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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Building my own Xen images

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In light of a few issues I’ve discovered with this post, I wouldn’t suggest that you use it as a guide. However, I’m leaving it up anyway, in case it is of use to someone. Instead, I recommend running pre-built cloud images from the OS vendor. I also recommend running using KVM for Enterprise Linux instead of Xen.

In my last post on Xen, I discussed using pre-built cloud images from Debian and AlmaLinux to create Xen virtual machines. These are convenient to use, but might not be ideal for certain use cases. For example, you might want certain packages to be included or excluded from your image, minimizing or even eliminating the role of cloud-init. Or for security reasons, you might not want to run an image from the internet on your local network. In this post, I will discuss how I built Xen images for AlmaLinux and Debian.

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