Category: TIL

  • TIL: k9s plugins

    k9s is a powerful Kubernetes terminal UI. Recently, I discovered how to add plugins, to make it even more powerful and integrate with other tools and systems!

  • TIL: Why there is /bin and /usr/bin, /lib and /usr/lib, etc on Unix systems

    If you’ve ever navigated around a Unix system you may have wondered why there are /bin and usr/bin directories or /lib and /usr/lib or /sbin and /usr/sbin – or like me, you just took it for something that probably has any meaning but isn’t relevant enough to look into. Well, today it became relevant: When…

  • TIL: scale down a Kubernetes DaemonSet

    A DaemonSet is supposed to run on all or some Kubernetes nodes, so scaling it down is surprisingly easy: Set a nodeSelector to some label which doesn’t exist, and the DaemonSet is scaled to 0. This will patch (-p) the DaemonSet and add a nodeSelector ( spec.template.spec.nodeSelector) which makes the DaemonSet run on all nodes…

  • TIL: Run a script on every k8s Node using a DaemonSet

    I’ve known that DaemonSets are used to run containers on all Nodes of a Kubernetes Cluster (or some), but I’ve never thought of using them to run a (shell) script on each node – a not-so-uncommon task when maintaining clusters! We need two resources: A ConfigMap and a DaemonSet.

  • TIL: named return parameters in Go



    Yet another piece of ✨ Go Magic ✨ I was reading through some Go code when I came upon a function that returned two things – []string and error – but the last line of the function just said return. I was confused how this worked, and since it was part of the standard library…

  • TIL: multiple git-identities on one machine



    Turns out you can have multiple Git identities alongside each other on one Machine without needing to set them locally for each repository! It still involves multiple .gitconfig files, but it’s a lot less work than configuring an endless amount of repos! First, set the global config like this: Now in ~/AOE/.gitconfig I configure the…

  • TIL: One-line list manipulation in Python

    In Python there’s a one-line syntax for iterating over elements of a list. I’ve always found it looked kind-of odd, and as I need to look it up all the time I decided to write a little TIL on this blog about it. There are more powerful one-liners documented on the Python Wiki.

  • TIL: Replace git URLs in Gitlab CI

    When working with Gitlab as a storage for Terraform or Ansible modules you probably access them using SSH, like git@gitlab.instance:group/project.git. This has the advantage that authentication is done using SSH keys and everybody on your team can access the repositories just like they’d do when cloning on the terminal – no need for entering passwords during…

  • TIL: Dots in /etc/sudoers.d filenames

    A tale of facepalms While reviewing some Ansible modules with a colleague we stumbled upon an issue with our user creation module, and for a briefe time couldn’t understand what was going on. The module in question creates multiple Linux users, adds them to groups, and enables some to use password less sudo via the /etc/sudoers.d config…

  • TIL: Bash select



    I was recently researching different bash prompts and stumbled upon an StackExchange answer which explains the different prompt types (PS1, PS2, PS3, and PS4). The answer explains how the PS3 prompt is used for commands like select. I did not know about select before, so that’s the real TIL here! […] PS3 is shown when the select command is waiting for…