A while ago my work team was assigned the task to migrate one firewall generator into a different one. Output were iptables rules for Linux servers in both cases. As we wanted to ensure a smooth transition, we were looking for a way to actually test the new rulesets before being deployed into production. A little bit of googling did not yield any results, so we came up with our own solution.

Recently, I stumbled across this brilliant Mastodon thread about 50 things to do with a software defined radio (SDR) by @blinry. Specifically this Toot about utility meters and Wireless M-Bus got me thinking about my own water meter. It is a rather recent model with a digital display and the display also shows a little RF symbol! I never put much thought into that, but seeing how it easy it might be to aquire data from the meter I thought I should give it a try.

Back in 2018 when I bought my first Unifi accesspoint for use at home, I set up a small Debian Stretch VM at my favourite hoster to run the Unifi Controller, nowadays known as the Unifi Network Server/Application. Back then, it was mostly “install Debian, install MongoDB, add the Unifi Repository and install the unifi package”.

My first encounter with Ansible was at a conference in Berlin during a talk given by the great Jan-Piet Mens in 2014. The only automation tool I had been using up until then was Puppet (not counting homegrown Bash scripts here). For the last ten years Ansible has been a constant in my toolbox, both work-related and private. The following points convinced me back in 2014:

Backups are important. They already were important before the days of ransomware. I operate multiple virtual (public) Linux servers and also have a Synology NAS at home and I would like to keep backups of any valuable data these systems hold.

Automating Ganeti is easily possible through its RAPI Interface. While that allows control over the cluster and its instances it is not very well suited to source events (unless you do constant polling and track state elsewhere). Luckily Ganeti features a hook system which allows the execution of arbitrary scripts/binaries upon events.

Building a new virtualisation cluster will require spending money on hardware at some point. To avoid underutilisation, unwanted overbooking or extremely unbalanced resource usage you need to make some decisions early on and then calculate based on those.

Ganeti is a virtualisation management solution for clusters which easily scales from few to hundreds of VMs. Please also see this blog post for an introduction to Ganeti.

During the next weeks and months I will publish a series of blog posts about Ganeti. It is a virtual machine cluster management solution which started as an internal project at Google and saw its first public release in August 2007. With the beta release of Ganeti 3.0 in June 2020, development has officially been taken over by the Ganeti Community from Google.