Computer Programming

	Passing PCI Devices to OpenBSD VMs from Linux Virtualization Hosts With processor and platform support, PCI passthrough allows a guest virtual machine to directly map host PCI resources, keeping them otherwise inaccessible to the host. Linux VM hosts running libvirt and KVM can support PCI passthrough, but there were a few pitfalls when communicating with OpenBSD guests.
	Deploying Sinatra Ruby Applications on OpenBSD in 2025 We're reprovisioning some of our application servers, which all run OpenBSD. As part of the modernization effort, we're using as much functionality baked into OpenBSD as possible. Ruby web applications in general, and Sinatra in particular, work well with this setup.
	Graphing 95th Percentile in Munin Like many ISPs, my colocation ISP bills bandwidth usage as 95th percentile. The ISP sends weekly and monthly bandwidth graphs to help in planning for bandwidth costs. While this is a common thing, it's not something that Munin supports out of the box, though rrdtool does.
	Jekyll Plugins, Custom Liquid Tags and Blocks During a recent bit of site maintenance, I DRYed up the Jekyll project for glitchwrks.com by creating custom Liquid tags and blocks for the site. These reduce code duplication, simplify and centralize configuration, and make the Markdown for writeups nicer.
	Building a Mail Server with OpenBSD, OpenSMTPd, and Dovecot I recently replaced a paid email service for a this small site with OpenBSD, OpenSMTPd, and Dovecot. OpenSMTPd is OpenBSD's internal SMTP server project, though as with OpenSSH it is also released in a portable form for other UNIX-like operating systems. Documentation is good, and configuration was pretty easy.
	Removing Cookies and Sessions from Rails 5 In transitioning from Sinatra to Rails for site services, I ended up removing pieces of Rails 5 that were not relevant to my project. This post covers removing cookies and sessions and their related configuration options, and what can and cannot be removed.
	Quick EPROM Timer Script I was erasing a pile of UV EPROMs today and got tired of interrupting what I was doing to go unplug the EPROM eraser when 20 minutes had elapsed, so I made up a little cable to control one of my relay-switched outlets using the serial handshake lines on a serial port. A few lines of Ruby later and, problem solved!
	Configuring MariaDB Replication MariaDB/MySQL replication provides an easy way to do realtime database backup, or allow for high-speed LAN access to a read-only reporting DB. Here's my method for getting a new replication slave running from an existing live DB.
	OpenBSD, Hurricane Electric, and Dynamic IPs Hurricane Electric allows dynamic updates for your end of the IPv6 tunnel, but OpenBSD needs to be made aware of the changes too. Here's a simple script to accomplish that.
	Reporting Dropwizard Uptime via Metrics Another simple configuration task with insufficient documentation! Get your actual application uptime from Dropwizard's metrics.
	Configuring an access log for Dropwizard projects One would think that access logging would be a common task for any application, but getting here took half a day of digging through incorrect documentation.
	Multipart HTTP POSTs with Groovy's HTTPBuilder Groovy's HTTPBuilder, an extension of Apache Commons HttpClient, allows multipart HTML POSTs, but documentation and useful/recent examples are lacking. Here's an example using non-deprecated methods to send multiple files and a few string params to a RESTful service and handle a returned binary.