During work building Docker executables, I ran in an interesting corner case. Fortunately the Docker IRC channel helped me to investigate with special credits to Ravensoul.
When you build a container as an executable you can use the ENTRYPOINT for your binary to execute and CMD as a default overwritable argument.
In most cases the CMD is the --help argument to provide a useful default behavior in case you just run the container without anything specified.
I’m using Mac OS X with iterm2, oh-my-zsh and spend 75% of my time in those terminals. It is totally annoying to me if I connect to a DHCP network and it screws up my hostname. Especially when I’m used to looking at the prompt which tells me the host I’m connected to.
It is possible to fix your computer name for several things using the scutil command which requires administration permissions.
I’ve found a link to the Mac OS X Server Worksheet which explains a few things in more detail.
Here is what I did to prevent my computer changing the host name.
I ran in some trouble with my Vodafone Easybox 904 xDSL. Even with 2Ghz and 5Ghz WLAN I had regularly drops. Had to turn on / off the WLAN on the device or had to reboot it to reconnect. Otherwise the VDSL line reguarly got disconnected, also replacing the Easybox from Vodafone didn’t helped, so I bought a Zyxel VMG1312-B30A.
I was listening to an interesting talk from Laura Frank from Codeship. In case you build or maintain a Continuous {Integration, Delivery} environment this definitely worth watching and they describe how they used LXC and now Docker to build their CI/CD infrastructure.
Interesting to me, the description in the YAML file reminded me quickly on a course I needed to pass during my study in parallel computing.
The exam had one section where you had to describe parallel and sequential processes with some high level constructs.
You had to describe a given time sequence graph for processes on n processors with the primitives BEGIN/END for sequential parts and COBEGIN/COEND for parallel processes.
We are all happy when we are able to get IPv6 connectivity for our new servers. In case the network is provided by someone else and some kernel settings you can get in some tricky situations.
With IPv6 there are so many addresses your Laptop and Mobile can have a unique public IPv6 address forever - pretty cool huh? The downside is, it would be pretty easy to trace every connection you ever do back to your device - this really not what you want! When you provide a service this behavior is not so useful. Otherwise there are several ways to autoconfigure your IPv6 configuration, beside DHCPv6 the interesting one is stateless address configuration.
Continue readingNotifications are important if you do monitoring. I never liked mail notifications from monitoring systems where all the information is hidden in non-sense text. Otherwise notifications never look the same, so I’m always forced to read all that useless crap again and again. This is an approach to improve the usability of monitoring notifications using more a table pattern which helps me to recognize useful information much quicker.
Probably a lot of E-Mail guys will hate me for the reason I’m using HTML in mails. The notifications work so much better for me so I don’t care. I’ve used just inline CSS and there is no JavaScript involved. All the things are in the mail and there are no external resources loaded. Here is how I work with OpenNMS mail notifications.
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Am 30.03.2015 haben wir im Büro 2.0 in Berlin einen Workshop mit OpenNMS durchgeführt. Die Zielgruppe waren NeueinsteigerInnen und alle die Interesse an Monitoring mit freier Software haben. Es wurden Installationszenarien, das Provisioning und beispielhaft diverse Monitore für Anwendungen und Dienste eingerichtet.
Die Slides sind unter einer freien CC-BY 3.0 lizenziert und stehen auf GitHub zur Verfügung.
Für diejenigen, die kurzentschlossen sind – hier eine letzte Erinnerung für einen kostenfreien Kickstart workshop zu OpenNMS. Die Registrierung und Anfahrt findet ihr unter:
I spent some time with preparing the OUCE 2015 and we use the free an open-source software frab as conference management system. I do most of my server automation with Chef and my playground is running with Vagrant. For this reason I decided to spend some time an built a Vagrant / Chef environment and contributed it back to the frab project. This guys do a really good job and IMHO it is the best free conference management system you can get. If you want to play with it feel free and give it a try and contribute.
Continue readingI spend a lot of time in the OpenNMS project and I love to work in free software and the workflows around it. We moved with our project from SourceForge to GitHub a few years ago and I think it was the right decision. There are now some established workflows in this ecosystem and they tear down borders between different open-source projects and here is an example of it.
I develop with IntelliJ IDEA and spend currently some time working in documentation of OpenNMS. We have migrated from Docbook XML format to AsciiDoc and started with the help of a few brave community volunteers a new documentation environment. I’ve found a plugin for IDEA which renders AsciiDoc and gave it a try to have a better workflow working on documentation and navigating through source code in just one program.
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