For a quick test of horizontal autoscaling of an NginX deployment, we need the following ingredients: a metrics server installation to be able to measure the POD's CPU an nginx deployment with a CPU reservation an auto scaler configuration a…
How I earned the Certified Kubernetes Administrator (CKA) badge – what would I do differently today?
What is the CKA? The Certified Kubernetes Administrator (CKA) certification proves you have hands-on experience managing Kubernetes clusters. How did I learn Kubernetes? Three years ago, I purchased a 4-day classroom Kubernetes Administration course (LFS458) from FastLane. It was not…
Linux Root Terminal on vocon Cloud – How to save your Image and re-launch a Container based on that Image
This blog post shows how you can run and manage your Docker images on vocon Cloud Desktop. We will launch an Ubuntu container, install git software as a root user and create and save the resulting Docker image on Docker…
Creating a StoryBook Hello World @ NextJS with the help of OpenAI based on ChatGPT – Part 1: chatting and creating a new Next.js app
Do we still need blogs, if there is ChatGPT around? I will test the OpenAI version of ChatGPT. In the long run, we intend to create a NextJS Hello World program with StoryBook. In this part, we will start chatting…
Kubernetes Task: assign a POD to a Node via Node Affinity – Cheat Sheet
Here, we show as shortly as possible how we can place a POD on the controlplane node on killerkoda CKA playground: Task: place a POD on the controlplane POD using Affinity Find documentation: kubernetes.io --> Documentation --> Search "affinity" -->…
Kubernetes etcd backup and restore – cheat sheet
This is a cheat sheet on how to perform backup&restore of the etcd server in kubernetes quickly. Test this on Killercoda Play with Kubernetes tl;dr Find reference: https://kubernetes.io --> Documentation --> Search "etcd backup restore" --> you will find: Operating etcd…
Playwright Hello World @ Angular 14
In this step-by-step guide, we will show you how to create your first successful e2e Playwright test for an Angular 14 project. Step 0 (optional): Start Cloud Desktop - or use your own environment If you need a development environment,…
Cheat Sheet: Install non-privileged podman v3 in a CentOS 7 Container
See how you can run a user space podman container inside another non-privileged container. For that, we create a CentOS 7 image with podman v3 installed. We spin up a Kubernetes non-privileged container from this image, and we show that…
How to enter a root shell session to a container without Docker – replace ‚docker exec‘ by ‚runc‘
The latest version of Kubernetes does not support Docker as a container runtime anymore. That is why many Kubernetes administrators have migrated their cluster's container runtime from docker to another container runtime like containerd or cri-o. Or they will do…
[SOLVED] WebStorm@CentOS Bug: Could not initialize class com.intellij.javascript.debugger.console.jcef.JCE
Do you know the following Error message? Error running 'Angular Application' # <- the name of the Debug Profile might be named differently in your case Could not initialize class com.intellij.javascript.debugger.console.jcef.JCE This happened to us on our WebStorm Cloud Desktop…
Upgrade Kubernetes Cluster – Cheat sheet
This is a cheat sheet created during the last upgrade of a CentOS-based Kubernetes cluster serving Developer's Cloud Desktops to our customers. TLDR; style. The commands are tested on CentOS 7. For Ubuntu, replace sudo yum install -y kubeadm-1.25.4-00 --disableexcludes=kubernetes…
Migrate Kubernetes Runtime from Docker to containerd
Migration of the kubeadm-based Kubernetes from Docker to containerd should be easy. In my case, it wasn't. Wrong information found on the Internet combined with the incompatibility of the used Kubernetes and containerd versions has caused major problems. Fortunately, I…
Hello ngrx/store @ Angular 13
This Angular ngrx/store tutorial will guide you through the steps of creating a hello world program using ngrx/store. After a brief motivation paragraph, we will learn how to use actions and reducers to manipulate stored states. A few unit tests…
WebStorm Cloud Desktop – the Best Javascript IDE in the Browser
WebStorm Cloud Desktop is now available as an installation-free application that runs in your browser. It provides you with JetBrains' well-known integrated JavaScript development environment with additional CPU and RAM and high internet speed. With the arrival of WebStorm Cloud…
IntelliJ Cloud Desktop – Instant free Remote Session with no Time Limit
IntelliJ Cloud Desktop by vocon IT GmbH is available as a free beta version on https://intellij-frontend.vocon-it.com/. Just register via GitHub or Google, and you are ready to start coding on IntelliJ Cloud Desktop in less than a minute. NEW (2021-11-26):…
Setting a Breakpoint for Debugging Spring Boot CORS Problems in IntelliJ IDEA (Cheat Sheet)
Super-short instructions how to place the breakpoint in an IDE in order to debug CORS issues in Spring Boot. The problem with debugging CORS (like any other filter in spring boot security) is, that any request is blocked before they…
Debugging Angular with Visual Studio Code (Cheat Sheet)
Find below quick step by step instructions on how to debug Angular applications with Visual Studio Code. Versions Tested on Visual Studio Code v1.52.1 on CentOS 7 (more recent versions do not work on CentOS 7) tldr; Ctrl-Shift+` & Create…
CKA Labs (19): Kubernetes Logging
In this article, we will have a look at Kubernetes logging. We will look, how Kubernetes logging is related to Docker logging. References: kubernetes.io: Logging Architecture Docker Logging: A Complete Guide by sematext.com Docker's official documentation on Logging Step 0:…
Tracing iptables on CentOS – Cheat sheet
This is a small cheat sheet that may help to troubleshoot iptables on CentOS systems. Most of the other articles on the Internet did not work, because CentOS has changed the way of activating tracing. Prerequisites iptables is installed and…
Avoid Docker created Files with wrong Permissions (Maven example)
This article helps you running Docker containers without polluting your filesystem with files owned by root. Most Docker images you find on Docker hub are designed to run as root inside the container. This can lead to your file system…
