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Author: hfreyther

QtVirtualKeyboard on Wayland

QtVirtualKeyboard on Wayland

For the last couple of years my focus was on the Osmocom project to bring Free Software to the world of telecommunication. With a group of enthusiasts we have implemented the components necessary to run a complete network using Free Software. The Rhizomatica project is using the software to connecting people that were left behind. Our tools enabled high impact security research leading, leading to improvements to privacy and security for all of us…. But during the last months I had…

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Static binaries (for Go with Docker)

Static binaries (for Go with Docker)

These days Go is quite popular for server based systems (read “cloud”) and one of the nice attributes is that compiling an application results in a single binary with no external dependencies (there is no “runtime” it has to link to). This makes deploying (read “copy to machine”) super easy and is a big contrast to something like Ruby on Rails and its thousands of dependencies. IIRC this feature was attractive to the developers of Qt’s coin (continuous integration agent)…

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Brain dump – what fascinates me

Brain dump – what fascinates me

A small brain dump of topics that currently fascinate me. These are mostly pointers and maybe it is interesting to follow it. Books/Reading: My kobo ebook reader has the Site Reliability Engineering book and I am now mostly done. It is kind of a revelation and explains my interest to write code but also to operate infrastructure (like struggling with ruby, rmagick, nginx…). I am interested in backends since… well ever. The first time I noticed  it when we talked…

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Creating a chroot for CentOS 7.3

Creating a chroot for CentOS 7.3

I have recently written some RPM spec files (and to be honest it feels nicer than creating debian packages) and could test installing the resulting packages on a cloud based CentOS 6.8 VM. After that worked I wanted to test the package on a CentOS 7 system as well. To my surprise my cloud platform didn’t have CentOS 7 images. There was RHEL7 with extra computing costs and several CentOS images with extra packages (or “hardening”) that also incurred extra…

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Leaving Marnixstraat 311-b

Leaving Marnixstraat 311-b

Long story short. The plan that made me move to Amsterdam didn’t work out and I had to explore what to do next. This means my wonderful time in Amsterdam ends a lot earlier than I had hoped. After exploring different options the most promising leads came through my existing network…but require relocation and leaving my beautiful place at Marnixstraat 311b. I will miss the atmosphere and way of life of Amsterdam, the beautiful view and the morning sun entering the…

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One year in Amsterdam

One year in Amsterdam

Last year I moved from Berlin to Amsterdam and maybe it is time for a quick recap and share my experience. Overall it is very positive. The life is very convenient. Amsterdam has less than a million citizen but it seems as busy as in any other big city. I am staying in the Jordaan with plenty of food options, most things are reachable by foot, some by bicycle. I have super markets around the corner that are open every…

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Funding the Osmocom Cellular project

Funding the Osmocom Cellular project

My friend and business partner has recently blogged about funding of the Osmocom Cellular Infrastructure Projects and while I want to write about the history of sysmocom s.f.m.c. GmbH I will focus on getting contributions (or as a replacement monetary support) for the project. First of all I think the existence of Osmocom and Osmocom Cellular made a significant difference. It is used to provide connectivity to those previously ignored (Thank you everyone involved with Rhizomatica!) and we enabled mobile communication security research. This…

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CAMEL and protocol design

CAMEL and protocol design

Today I want to share the pain of running a production 3GPP TCAP/MAP/CAP system and network protocol design in general. The excellent Free Software ASN1/TCAP/MAP/CAP stack (which is made possible by the Pharo live programming environment) I helped creating is in heavy production usage (powering standard off-the-shelf components like a SGSN, an AuC or non-standard components to enable new business cases) and sees roaming traffic from a lot of networks. From time to time something odd comes up. In TCAP/MAP/CAP messages but also…

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MariaDB Galera and custom health probe for Azure LoadBalancer

MariaDB Galera and custom health probe for Azure LoadBalancer

My Galera set-up on Kubernetes and the Azure LoadBalancer in front of it seem to work nicely but one big TODO is to implement proper health checks. If a node is down, in maintenance or split from the network it should not be part of the LoadBalancer. The Azure LoadBalancer has support for custom HTTP probes and I wanted to write something very simple that handles the HTTP GET, opens a MySQL connection to the destination, check if it is connected to…

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Troubleshooting Kubernetes/Azure Storage

Troubleshooting Kubernetes/Azure Storage

In my previous posts I wrote about my set-up of MariaDB Galera on Kubernetes. Now I have some first experience with this set-up and can provide some guidance. I used an ill-fated TCP health-check that lead to MariaDB Galera blocking the originating IPv4 address from accessing the cluster due to never completing a MySQL handshake and it seems (logs are gone) that this lead to the sync between different systems breaking too. When I woke up my entire cluster was down and…

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