Talk I gave at #LISA2018. I've given this talk as a half day tutorial, at LISA2018 I gave it in 90minutes. The bulk of the talk is laying a solid foundation on how Linux works. Slides

My iPad got updated to 11.3 and I lost the ability to use my usb-midi interface reliably. I had an M-Audio Uno which worked great on 10.3.3. On 11.3 it keeps stopping and a dialog is displayed stating that the "accessory is unsupported".

I think this is related to the M-Audio using more than 100mA. My lightning adapter couldn't inject voltage, so I looked at getting a Bluetooth MIDI adapter.

I made a data_hash backend for hiera that uses the puppet certificate certname to connect to a remote http service and retrieve hieradata for a node. The http backend is up to you, in my implementation I also verified the certificate was signed by the Puppet CA.

This backend uses data_hash, so that it only looks up hiera once per catalog compilation. If it finds hieradata for a node, it updates the hiera cache.

The github repo is located here https://github.com/uphillian/http_data_hash

I wanted to export my playlists with Plex, I installed Export Tools and ended up with CSV files.

I looked around and couldn't find something to convert those to m3u. I did get a m3u8 file but it didn't work with my devices...

I made a quick python script to convert the csv to m3u...it's possibly useful to someone else...maybe.


#!/usr/bin/env python

import csv
import getopt
import sys

I find this really useful, just a call out to sed so I don't have to remember the syntax.


ssh_delete_key() {
sed -i -e ${1}d ~/.ssh/known_hosts
}
alias sshdel=ssh_delete_key


While at LinuxFest Northwest I picked up an Old Raspberry Pi from the Yard Sale. I didn't realise it was a Model A...took me a while to figure out a use for it, not much memory or processing power.

I use a USB camera on my work laptop and the camera sometimes doesn't show up in my video conferencing app. I verified that the camera is showing in the usb list with lsusb (a script I got from https://github.com/jlhonora/lsusb which is great btw).

dtruss showed that the VDCAssistant was being accessed by my apps, so I tried killing that and boom the camera shows up.

So now I aliased camkill='sudo pkill VDCAssistant'

I spent far too long diagnosing why this worked in one set of hosts and not another. When the vrrp_script fails on one host, it's supposed to move the service to the other host, that's the whole point right?

Tutorial I gave at LISA2016

git crash course - slides
tutorial workbook

Talk I gave at PuppetConf 2016
Slides are here