A no fuss Docker install on Rapberry Pi 2

During CloudFleet development, we had some problems in finding a consistent way to install Docker in Debian Jessie on ARM (Raspberry Pi 2). Debian moved us around between mirrors a bit and then eventually settled on Docker 1.7.1 which doesn’t work on ARM (Socket operation on non-socket). Luckily, we found a nice Docker .deb package that works on ARM thanks to the Hypriot community (check the link for the latest Docker version). To use it, simply do:

wget http://downloads.hypriot.com/docker-hypriot_1.8.2-1_armhf.deb
dpkg -i docker-hypriot_1.8.2-1_armhf.deb

Or if you use Ansible, use this snippet: Continue reading A no fuss Docker install on Rapberry Pi 2

Installing CyanogenMod on HTC Sensation

After using the stock Android ICS that came with my Sensation for a couple of years and getting fed up with it crashing and being slow all the time, I decided to try out the CyanogenMod (CM) everyone was talking about. When I started with this endeavour, I was a bit overwhelmed by the amount of incoherent/incomplete resources all around. In this post, I’ll try to summarise the steps necessary to install it in a more human way to help others achieve the same goal.

HTC Sensation and the material design of CM 12
HTC Sensation and the material design of CM 12

Continue reading Installing CyanogenMod on HTC Sensation

A talking Raspberry Pi using Resin.io

Just trying out resin.io which is a nice new service that enables you to deploy apps to Raspberry Pi devices in a Heroku-like workflow:

git push resin master

In this post I’ll explain how I deployed a simple app that recites “N green bottles” written in Node.js to my Raspberry Pi via Resin.io – without having to ssh to the Pi even once. Continue reading A talking Raspberry Pi using Resin.io

CPU frequency scaling in Ubuntu

Changing CPU frequencies can be interesting to measure certain energy efficiency aspects. To manually change the CPU frequency in Ubuntu, first install cpufrequtils to get the additional commands:

sudo apt-get install cpufrequtils

See the available CPU frequencies, the current frequency and governor per core.

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Changing MySQL database encoding

For some time now, I had a pending task of converting the latin1-encoded MySQL database powering this site into utf8. I finally managed to do it after getting some advice from the kind people at a Vienna WordPress meetup.

The essence is that out of all the methods suggested in the official documentation, what worked best for me was dumping all the data to a text file, marking up and encoding it as utf-8 in a text editor and then importing it into a new database (instead of working on the production DB) that we point the wp-config.php file to after everything is verified.

Continue reading Changing MySQL database encoding