Set up an ODROID XU4 RAID Server with Cross-Compiled Docker Images for ARM

ODROID XU4s are awesome. They are 8-core, 2GHz ARM single-board computers (SBCs) with Gigabit Ethernet and USB 3.0 connections. They only have 2GB of DDR3 RAM, but when paired with a CloudShell2 case and a couple of HDDs (or SSDs), they become an impressive NAS, or better, dedicated network-activity drivers for other projects.

Puppet Several Headless Chrome Instances Behind Different VPNs in Docker, No IP Leaks

For my machine learning projects, I need data you just can’t buy. This requires SPA (Single-Page App) web data extraction involving multiple clicks and page scrolling that curl can’t handle. Headless Chrome puppeted by RDP (Remote Debug Protocol) is a brilliant solution for this. Here is how I orchestrated several headless Chrome instances across several VPNs in Docker.

Flash AVR Amtel ATtiny Chips with a Modified CH341A ISP Programmer

I bricked a lot of ATtiny85 Digistump chips while I was building a custom bootloader. Here is how I unbricked them and flashed onto them bootloaders with less than $5 of hardware using an AliExpress CH341A BIOS programmer and some soldering. The problem is that the CH341A is not designed for ATtiny chips, but for flashing motherboard BIOS chips, so I had to hack it.

Build a Secure MFA Web-Browser-Based Remote Desktop Gateway on a Raspberry Pi

Let’s say I’m in a Starbucks or the airport (or both) and I want to connect to my Windows (or OSX or Linux) machine to check on things. Maybe I don’t want to take my primary computer with me on vacation; maybe I’ll just take a Chromebook. Behind a restrictive firewall all we have is port 80 and port 443 (no VNC or RDP allowed), so let’s make a secure web-based remote desktop gateway with a Raspberry Pi, Docker, and Cloudflare.

Random Useful Linux Commands

These useful Linux commands and snippets are a reference for myself, all in one place, so I can refer to them quickly during my workflow without searching for them again and again. These include networking, git, grep, journald, ss/netstat, process uptime, and more. More are added as I go.

Block Malicious and Obnoxious Ads and Scripts at the DNS Level

Ads are getting more and more aggressive. Some ads are even malicious. Some sites even load crypto-currency mining scripts in the background in JavaScript. Users have discovered that a lot of traffic is advertisement or tracking scripts, and putting a damaging strain on our mobile device data plans and batteries. Here I explain how to safely setup Pi-hole – a network-wide ad-traffic blocker – in a Docker container on an external Linux device as a hardware DNS server to block ads.

Profile Remote Java Apps with VisualVM or JMC

Sometimes remote Java apps leak memory or are killed by the OS. Let’s connect through an SSH tunnel to a remote JVM running on an embedded Ubuntu system and profile memory and CPU usage with free tools VisualVM and JStatD, or Java Mission Control. No firewall adjustments are needed. We’ll also set up JMX connections to allow remote heap dumps and garbage collection. Finally, I’ll explore the features of VisualVM.