blockdev.io

ngrok

A free custom domain for ngrok by using Amazon Web Services

Introduction ngrok and similar tools are great for providing public access to local services, often for development purposes. I primarily use it for exposing an API being developed locally so that a webhook callback can interact with it, for example an inbound email callback from mailgun - it's very useful

mikrotik

Creating a completely isolated guest network using Mikrotik hardware

Creating a physically isolated guest network using iptables and 802.11q VLANs.

git

Hub Clone Tool - Clone all your GitHub Repositories with one command

Introduction I work with a large number of repositories, mostly on GitHub, some are my own but most are for work, and the volume only grows since we complete a lot of projects each year. I find it useful to be able to clone everything I need in a number

Making persistent changes on a read-only Raspberry Pi

Introduction The ability to boot a Raspberry Pi from a read-only file system can be advantageous for a variety of reasons and I've previously written a number of posts that look at use cases and implementation approaches. A key challenge is then making changes, often this requires a reboot to

mysql

MySQL Workbench, Ubuntu 20.04 and App Armor

Recently when installing MySQL workbench on a clean Ubuntu 20.04 install I've run into the following error when connecting locally using a stored password: "An AppArmor policy prevents this sender from sending this message to this recipient.." This post on MySQL forum suggests its a permissions issue between MySQL

arduino

RGB LED Electric Drums - MIDI x Arduino x WS2812

Introduction This is another just-for-fun project which was completed a couple of years ago. I have a number of instruments that I play for the pleasure of it, having had an electronic drum kit for a few years and having had and acquired all sorts of electrical, I was interested

Raspberry Pi

Mini Guide: DHCP Controlled Hostname on Raspbian

DHCP Controlled Hostname on Raspbian Note: This note was originally in the Network Booting a Raspberry Pi 3 from an Ubuntu Server post. In theory the configuration should be as simple as stated below: { ... host pi3-1 { hardware ethernet b8:27:eb:41:8e:fa; fixed-address 192.168.1.59; option

Raspberry Pi

Mini Guide: DHCP Reservations

DHCP Reservations Note: This note was originally in the Network Booting a Raspberry Pi 3 from an Ubuntu Server post. To make life easier DHCP Address reservations can be added in the main body of the DHCP config so that each MAC Address gets assigned the same IP: { ... host pi3-1

Mini Guides

Mini Guide: NFS Debugging

NFS Debugging Note: This note was originally in the Network Booting a Raspberry Pi 3 from an Ubuntu Server post. Initially when trying to understand whether the Pi was booting from the network or not it was useful to enable NFS debugging with rpcdebug -m nfsd -s proc which reports

Mini Guides

Mini Guide: Controlling Screen Blanking

Controlling Screen Blanking Note: This note was originally in the Raspberry Pi 2/3: Chromium in Kiosk mode post. The screen can be turned off using the following command: xset -display :0.0 dpms force off And on: xset -display :0.0 dpms force on These could be used in

Mini Guides

Mini Guide: Pi User and Management User(s)

Pi User and Management User(s) Note: This note was originally in the Raspberry Pi 2/3: Chromium in Kiosk mode post. Auto-login to the GUI works regardless of the pi user's password. It is worth changing this for security, potentially creating a management user which requires a password to

Mini Guides

Mini Guide: Raspberry Pi Memory Split

Memory Split Note: This note was originally in the Raspberry Pi 2/3: Chromium in Kiosk mode post. The memory available to the GPU can be configured by: * sudo raspi-config * Option 7 (Advanced) * Option A3 (Memory Split) This may be useful when rendering more visually-intensive pages.

Mini Guides

Mini Guide: Raspberry Pi Overscan and HDMI Modes

Overscan and HDMI Modes Note: This note was originally in the Raspberry Pi 2/3: Chromium in Kiosk mode post. In some cases the image may not fill the screen. The overscan setting below can help, as well as forcing certain HDMI modes as document [here](From https://www.raspberrypi.

Raspberry Pi

Mini Guide: Raspberry Pi Serial Console

Serial console Note: This note was originally in the Raspberry Pi, overlayfs read-write root, read-only NFS base post. It's quite easy to listen on the serial console as you don't have to worry about the voltage differences. Full documentation here. I have many Prolific Technology, Inc. PL2303 Serial Port devices

Raspberry Pi

Mini Guide: Easier Script Debugging

Debugging Note: This note was originally in the Raspberry Pi, overlayfs read-write root, read-only NFS base post. In trying to get the various options out there working I found a number of debugging strategies helpful, they're mostly simple - First, set -v - put this after the #!/bin/sh (or

Read Only

Mini Guide: Read only Raspberry Pi (without NFS)

Without NFS Note: This note was originally in the Raspberry Pi, overlayfs read-write root, read-only NFS base post. This setup described in the article above also works without the NFS setup. As we plan to have no 'proper' storage and RAM limits the size of writes we can store there's

Raspberry Pi

Mini Guide: Watching the file-system on Linux

Watching the file-system Note: This note was originally in the Raspberry Pi, overlayfs read-write root, read-only NFS base post. NFS logging appeared to be quite opaque to me, so it proved useful to be able to observe the relevant file-system activity. We can watch the file-system activity (when the Pi

linux

Linux Configuration Management at Home with SaltStack

Introduction It's not uncommon to need to re-install a computer, in the days when I used Windows more it seemed a good way to re-gain performance, as well as eradicate any viruses or other malware. These days its often because I've upgraded Ubuntu and it hasn't really been seamless. Admittedly

Easy AWS Lambda function deployment with Apex

Introduction Recently I have been spending a lot of time playing with AWS Lambda functions for various tasks like (small) ad-hoc data imports, billing alerts and building Amazon Alexa Skills. For simple tinkering I was reluctant to do more than use the web-(and cloud9)-based IDE to avoid the

Gigabyte Aero W15 Keyboard and Linux (Ubuntu)

Introduction TL;DR - Here is the GitHub link: https://github.com/paul-ridgway/aero-keyboard, which documents the protocol and has a few utility scripts and examples. For the first time in a long while I have decided to get a personal laptop. After debating the costs of a new one

Raspberry Pi, overlayfs read-write root, read-only NFS base

Introduction My recent projects and write-ups (linked below) have involved Network (PXE) Booting a Pi and loading the root file-system from NFS. It works well but any files operations are quite slow, and generally numerous file writes can occur when using apps. Additionally I don't want temp file or accidental

Network Booting a Raspberry Pi 2

Introduction While going forward it would be ideal to only use Rasberry Pi 3s for Network Booting (or generally) I have a number of Pi 2s left. Being able to re-use these in the same way means less waste. I found it much easier to test this approach after having

Raspberry Pi

Raspberry Pi 2/3: Chromium in Kiosk mode

Introduction At work we have a number of screens around the office used for monitoring. To keep the costs down, solution versatile and setup simple the plan was always to use a Raspberry Pi per screen to display data in a browser (Kiosk Mode). To manage configuration and updates without

Network

Network Booting a Raspberry Pi 3 from an Ubuntu Server

Introduction I often use Raspberry Pis as Chromium Kiosk Clients to monitor our systems and infrastructure, and to reduce the overheads I also Network Boot them for this and a few other uses (hopefully coming soon) so that they are easy to manage collectively without needing to flash numerous SD

Fixing: uninitialized constant OpenSSL::Digest::DSS on Mac OS Sierra

I recently installed Ruby (via RVM) on a Mac I use for work, and upon trying to run rails (after the usual bundle install) I got the following error: There was an error while trying to load the gem 'secure_string'. (Bundler::GemRequireError) Gem Load Error is: uninitialized constant OpenSSL: