Christian Hollinger

Software Engineering, GNU/Linux, Data, GIS, and other things I like

18 May 2025

A Distributed System from scratch, with Scala 3 - Part 3: Job submission, worker scaling, and leader election & consensus with Raft

4,308 words, ~17 min read

Upgrades to Bridge Four, the functional, effectful distributed compute system optimized for embarrassingly parallel workloads: Updating Scala, auto-scaling workers, and implementing leader election with Raft (or half of a replicated state machine).
01 Jan 2025

My 2025 Homelab Updates: Quadrupling Capacity

4,615 words, ~18 min read

...because everybody wants 40 cores, 256GB RAM, and 130TB storage. Some 2025 updates to my homelab, which might or might not be getting out of hand.
25 Aug 2024

Why I still self host my servers (and what I've recently learned)

4,581 words, ~18 min read

A short story on why I still go through the effort of self hosting servers and some things it taught me recently.
19 Feb 2024

Improving my Distributed System with Scala 3: Consistency Guarantees & Background Tasks (Part 2)

2,715 words, ~10 min read

Improving Bridge Four, a simple, functional, effectful, single-leader, multi worker, distributed compute system optimized for embarrassingly parallel workloads by providing consistency guarantees and improving overall code quality (or something like that).
26 Oct 2023

Moving a Proxmox host with a SAS HBA as PCI passthrough for zfs + TrueNAS

1,449 words, ~5 min read

How to move a Proxmox host to a new m.2 SSD when using a LSI SAS HBA card to realize PCI passthrough for HDDs for zfs + TrueNAS.
19 Jun 2023

Building a functional, effectful Distributed System from scratch in Scala 3, just to avoid Leetcode (Part 1)

9,425 words, ~37 min read

Building something that already exist (but worse) so I don't have to think about Leetcode: Bridge Four, a simple, functional, effectful, single-leader, multi worker, distributed compute system optimized for embarrassingly parallel workloads.
08 Apr 2023

Migrating a Home Server to Proxmox, TrueNas, and zfs, or: How to make your home network really complicated for no good reason

7,374 words, ~29 min read

Going from a single, bare metal Debian server to two physical machines, 7 VMS, 5 zfs pools, and a whole bunch of data and networking: An experience. Also, stuff broke.
24 Jan 2023

QGIS is the mapping software you didn't know you needed

4,012 words, ~16 min read

QGIS is incredible: You can build maps that make use of the absolute wealth of public data out there and put Google Maps to absolute shame. This article is doing just that.
08 Sep 2022

Tiny Telematics: Tracking my truck's location offline with a Raspberry Pi, redis, Kafka, and Flink (Part 2)

5,022 words, ~20 min read

Tracking vehicle location offline with a Raspberry Pi, Part 2: Apache Flink, scala, Kafka, and road-testing.
29 Aug 2022

Tiny Telematics: Tracking my truck's location offline with a Raspberry Pi, redis, Kafka, and Flink (Part 1)

5,370 words, ~21 min read

Building custom Linux images, dealing with a 40 year old GPS standard, & trying to shoehorn functional programming into Python: Tracking vehicle location offline with a Raspberry Pi. (Part 1)