Posts

Overriding / Patching Linux System Serial Number

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I'm a big fan of test driven development  (TDD) for infrastructure components. I'm currently working on a hardware-related topic where we also use the system serial number as identifier. To create a proper integration test, we need to be able to start a system and set the serial number to a known value. This can easily be done with the help of virtual machines like in VMware or VirtualBox , but I couldn't find a way for changing the system serial number on hardware boxes, cloud VMs (e.g. on Alibaba Cloud) or other Linux system. Problem Analysis I was thinking: Linux is the operating system where I can potentially do everything . So how hard can this be? After some digging around I found out that there are those main sources for the serial number on Linux: /sys/firmware/dmi/tables/DMI contains a binary blob of Desktop Management Interface data provided by the kernel and the dmidecode utility is commonly used to decode

Mission Impossible: Complete Disaster Recovery for Google Workspace

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I'm a frequent user of Google Workspace and even accept the switch from free to paid for my family domain . One topic has always been on my to-do list: Proper backups to support disaster recovery after a major problem. It turns out that Google Workspace has a significant flaw: It is technically impossible to create a full backup of all data and to restore that! Google simply doesn't offer any API for that. As a result, all backup vendors are forced to work with the regular APIs. As a result, not everything in Google Workspace can be stored in a backup, e.g. Google Sites (new, not classic). Some content, like Google Drawings and others, can only be backed up as a static file (e.g. PDF) and not restored into a new Google Drawing. Google itself doesn't offer much on backup and disaster recovery: Recover deleted files and folders for Drive users Restore deleted shared drives or their files How to mitigate ra

FOSS Backstage 2022 — A True Community Conference

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Attending the FOSS Backstage 2022 conference on "Community, Management & Compliance In Open Source Development" was a real highlight for me: A conference About Open Source In Berlin In person! I fondly remember the first edition in 2018 ( YouTube Archive , Flickr Photo Archive ) which actually helped with my Open Source work at DB Systel . Given the ongoing COVID pandemic, the conference was very small, with only about 60 people attending in person and 200 additional remote participants. That, and the conference location in a co-working space, gave the event a very intimate and personal feeling. More like a true community meet-up than a polished commercial event. The 2022 edition put the major focus on major Open Source related initiatives and community topics, but it didn't talk much about the practical sides of Open Source compliance, e.g. the OpenChain Project . I spoke with the organisers about that, and they indicated that future F

Fixing Chrome Color Printing on Linux with HP Color LaserJet M880

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It seems like I can't get a printer that "just works". I recently decided to replace our HP X476 printer with something nicer and bigger, an HP Color LaserJet M880 ( background story & review in German ). And of course there is something that needs fixing: The Chrome browser on Linux wouldn't let us print in color, even though all other applications had no problem to print in color. Even with Chrome color printing was possible, if one used the system printing dialog instead of the built-in Chrome print preview. This strange behavior of course piqued my curiosity. After some digging around I found out that the Chrome browser needs to parse and understand  the printer driver PPD! Chrome tries to find out how to configure color or grayscale printing in order to offer the user the choice. If Chrome can't understand the printer driver then it simply doesn't offer the choice between color and grayscale — and then some printer driver default can ch

A Login Security Architecture Without Passwords

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Following up on Lifting the Curse of Static Credentials and Eliminating the Password of Shared Accounts , I have many discussions about why we would benefit from removing password prompts for website logins. Let's dig deeper into the details and show why removing password prompts leads to a  safer security architecture . Update 11.03.2022: Added more details about business vs. consumer websites and additional security suggestions surrounding WebAuthn Problem Space For context, imagine a website that needs to identify online users via their email address. We assume that the website in question is not the primary email system of a user but some other website, e.g. an e-commerce shop system or a collaborative productivity tool. As a User As a user of that website I want to easily sign up for an account have an easy way to login into the account be sure that my account is protected from others or attacks be able to easily recover access to my account i

Thank you Deutsche Bahn, we had a good time

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As I am writing this, my last minutes of employment at Deutsche Bahn ( DB Systel , DB) are running out. Tomorrow I will start my new job at Forto – time to look back at my 4 years with DB. This was my first time working at a really large company, even a corporation. 320,000 employees is really a lot and till the very last week I met new people with interesting topics. Working at such a large company – especially one with so many subsidiaries – was a novel experience for me. I learned a lot about corporate politics and about the motivating factors in such a large organization. For me these last 4 years were a very good time, where I was allowed to work in a very interesting position (Chief Architect Cloud in the CTO Team of DB Systel) and together with very interesting and inspiring colleagues. I learned something from every one of my colleagues, and I would like to take this moment to tell you all a big thank you for this time together. A lot happened during those years, and I

The Demise of KaiOS - Alcatel 3088X

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I was really excited, when Firefox OS became commercially available as KaiOS for "smart" feature phones. Unfortunately the high hopes I had put into this platform have been utterly shattered. I was recently looking for a button phone that had only three requirements : very good battery run time, at least several days or a week of standby without charging easy backup or even synchronization of the contacts VoLTE support to benefit from LTE coverage  In Theory... On paper, KaiOS phones look like the perfect match for those requirements. PhoneCopy for KaiOS is a cloud synchronization service that comes with an app for KaiOS (and many other platforms) to synchronize contacts and other phone content to the cloud (and back). With batteries of 1500 mAh and more , KaiOS phones have the potential to deliver outstanding battery performance. The Alcatel 3088X , for example, boasts "up to 300h standby and more than 7h talk time" with a 1530 mAh battery: Battery specification

The GitOps Journey

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I talked about this at the GitOpsCon EU 2021 and at Berlin DevOps Meetup 2021-11: The GitOps Journey Video The GitOps Journey Slides I also talked about this in a more expanded version at Enterprise Code 2021 and Continuous Lifecycle 2021: The Role of GitOps in IT-Strategy Slides And if you understand German, please watch this full features recording of my talk: GitOps is most definitely one of the hype words of 2021. No self-respecting tool fails to market itself as a "GitOps tool, even if is only remotely related to the GitOps principles defined by the CNCF GitOps Working Group . But where does GitOps fit into an IT strategy? In my opinion GitOps should be the centerpiece of every modern IT strategy! The GitOps journey takes the hype surrounding GitOps to build a solid, automation-focused, long-term sustainable IT strategy. A strategy that uses standard "GitOps" tools together with o

10€ remote doorbell

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Our door bell is not very loud and we don't hear it in the kitchen when the internal doors are closed. We already missed people calling at our apartment door because of this. To solve this problem I found a 10€ remote bell that sits in the kitchen and rings whenever somebody rings our door bell. Initially I wanted a fancy WIFI based solution based on an ESP32 that would call me via SIP... But in the end this simple solution is "good enough" and has the benefit of zero maintenance. My solution is based on a kinetic wireless doorbell  (batterielose Funktürklingel) that has two components: A ringer that sits in a power socket and a transmitter without batteries. The "without batteries" part is really important as it allows a direct connection and integration of the transceiver into the door phone. As it happens, what I needed was available for 10€ at a local supermarket, but you can easily find this type of doorbell in online stores as well. The ringer contains a l

How did GitOps get started? An interview with Alexis Richardson

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As part of the research for my upcoming GitOps article in the iX magazine , we -  Johannes Schnatterer and I  - had the opportunity to interview Alexis Richardson , founder & CEO of WeaveWorks , about how he invented GitOps - both the concept and the term. The interview covers Alexis' views on GitOps, Kubernetes and gives an interesting insight into his company and their take on Open Source. The following transcript is auto-generated by YouTube, please excuse any mistakes:

Google Workspace for Education Cost Calculator

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This week Google announced the new Google Workspace for Education features and pricing. The former Enterprise subscription continues as "Education Plus" subscription and there are two new paid subscriptions "Education Standard" and "Teaching & Learning Upgrade" (T&L Upgrade).  Of course the free version continues as "Education Fundamentals". Check out the detailed feature overview at the Google Education homepage.  Completely new are the pricing models: Education Standard and Education Plus are billed by the amount of students, with complimentary staff licenses at a 1:4 ratio (every 4 students buy a staff license). Teaching & Learning Upgrade is billed by the amount of teachers. All licenses are billed yearly, states the FAQ at the bottom of the page. In comparison, the previous "Enterprise for Education" subscription was billed by the amount of staff, with 10 complimentary student licenses for ev

Measuring video lights with a colorimeter

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After more than half a year of home office I decided to improve my setup by adding proper lights to my work space. Following a recommendation I bought 2 video lights off Amazon, and then at the recent Black Friday week I bought the same video lights in a set of 2 with tripods (because the set cost less than I paid previously for the 2 single units). To my dismay I discovered that the 4 video lights, same brand and same model, actually looked different and performed different! The question is, which video light is more "correct" and therefore better to keep? I wanted to keep two and return two because I don't need four lights. Two is more than enough. The lights can be adjusted for brightness and for color temperature, but all the four lights would look different at the same setting. So which light was correct? Which to keep? After breaking my head for a bit I suddenly remembered the old colorimeter I have in my cabinet. It actually does
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