In this blog post, I have summarized how I have set up a single-node Kubernetes cluster version 1.32 on a fresh Ubuntu 24.04 with dual stack IPv4/IPv6 support. Tested with: Ubuntu 24.04 Kubeadm 1.32.3 CRI-O 1.32 Calico 3.29.3 Part 1:…
Migrate Kubernetes Runtime from Containerd to CRI-O
Why Replace Containerd with CRI-O in Kubernetes? Switching container runtimes again might seem unnecessary after the recent move from Docker to containerd. However, CRI-O offers unique features like enhanced Kubernetes compatibility and improved security. For example, I used CRI-O to test…
Kubernetes horizontal POD Autoscaling – Hello World
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 to enter a root shell session to a Container with containerd or CRI-O using ‚runc‘ or ’nsenter‘
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…
Metricbeat on Kubernetes – Kubernetes Series (11)
Three ways of installing Metricbeat (a performance monitoring solution) on Kubernetes are compared: native vs. helm with set options vs helm with values options. Metricbeat helps us monitoring performance indicators like CPU, Memory, Disk and many more on your Kubernetes nodes. We will show that (and why) installing Metricbeat via helm based on values file is the quickest way of installing Metricbeat. You just need to copy the Metricbeat chart's values file, adapt it to your needs and run a helm command in order to roll out the Metricbeat agent to all nodes of your Kubernetes cluster.
Mesos and Marathon REST API via cURL — A Hello World Example
In this hello-world style blog post, we will learn how to create load balanced Docker services in an open source DC/OS & Mesos environment. For that, we will perform Mesos and Marathon REST API calls using simple cURL commands. First, we will…
Getting Started with DC/OS on AWS
In the step-by-step tutorial Getting Started with DC/OS on Vagrant, we have learned how to install a MesosPhere DC/OS data center operating system locally. This time, we will install a DC/OS system on AWS Cloud: existing AWS CloudFormation templates will help us create…
Vagrant on CentOS 7 – Setting up Test Environments the easy Way
After stumbling upon several guides still describing a Vagrant installation via a RubyGem - which is no longer supported - the following article was created and will provide a quick setup guide on how to setup Vagrant on CentOS 7.…
Jenkins Part 7: Pipeline as Code
In this blog post, we will introduce the Jenkins Pipelines, an increasingly popular plugin that helps defining versatile Jenkins workflows as Groovy code. Traditionally, Jenkins is administered by a graphical Web interface. Now, the Pipeline plugin allows teams and DevOps…
Getting Started with DC/OS on Vagrant
In the course of this Hello World style tutorial, we will explore DC/OS, a Data Center Operating System developed and open sourced by Mesosphere with the target to hide the complexity of data centers. We will install DC/OS on your local PC or Notebook…
Jenkins (6): BrowserStack Integration – Automated Cross Browser Testing
With the BrowserStack cloud-based solution, there is no need to buy many different hardware types for testing your website for many different mobile devices and operating systems. In this blog post about Jenkins BrowserStack Integration, we will learn how to integrate BrowserStack-based automated…
Testing any Browser on any Hardware using BrowserStack – A Protractor Cross Browser Testing Example
This time we will learn how to test any web site (including your front end software) using many different Internet browsers by integrating a cloud-based cross browser test solution named BrowserStack. We will perform Protractor tests for AngularJS using the…
Jenkins Part 5.1: Using the Job DSL for automatic Creation of Jenkins Jobs
Today, we will learn how to use the Jenkins Job DSL Plugin to create new Jenkins jobs at a push of a button. We will show how we can use Groovy scripts for defining a "Hello World" Jenkins freestyle project and…
Jenkins Part 4.2: Code Quality Tests via Checkstyle
Today, we will show how to use Checkstyle for improving the style of Java code. First, we will add Checkstyle to Gradle in order to create XML reports for a single build. Jenkins allows us to visualize the results of more…
Jenkins Part 4.1: Functional Java Tests via JUnit
You also think that functional tests are one of the most important ingredients for delivering high quality software? You share my opinion that we should help the developer automating this task in order to get comparable results and to receive meaningful trend reports? I…
Jenkins Part 3.1: periodic vs triggered Builds
Today, we will make sure that Jenkins will detect a code change in the software repository without manual intervention. We will show two methods to do so: Periodic Builds via Schedulers: Jenkins periodically asks the software repository for any code changes…
Getting Started with Mesos Resource Reservation & Marathon Watchdog – A „Hello World“ Example
Today, we will introduce Apache Mesos, an open source distributed computing system with the target to allow applications to run on a computer cluster as if it was running on a single computer. On top of a Mesos cluster, we…
Jenkins Part 2: automated Code Download and Build (Gradle + Maven)
NEW (2017-01-02): you now can immediately start with part 2 (this post) without going through the steps of part 1. A corresponding pre-installed Docker image is provided. NEW (2017-01-05): I have added the Maven build path with a fat executable…
Cassandra „Hello World“ Example
Today, we will introduce Cassandra, a distributed and resilient, highly scalable noSQL database. For simplicity, we will run a cluster within Docker containers. We will test the resiliency functions by killing one of two containers and verifying that all data…
Jenkins Part 1: Installation the Docker Way
In this blog post, we will deploy and get started with Jenkins, the most popular open source tool for Continuous Integration and Continuous Deployment. As a modern way of installing, we install a Docker host and deploy a Jenkins Docker…
