In some OpenShift environments for building and delivering software we notice that the needs of developers, arguably a group of people who will have a great deal of contact with the platform, are not met as thoroughly as would have been possible.
Especially when it comes to software testing there is often much room for improvement. The usage of container platforms can improve testing techniques a lot but might also be a major blocker when it comes to the provided infrastructure. Good testing is already hard. Everything that makes it even harder, by forcing your developers into workarounds or compromises on testing quality will result in larger round trips, more testing effort, less valid testing, in short: wasted time.
So in this mini series of blog posts we will have a look into some possible fields of improvement and give recommendations on how to fix the respective situation.
Today we evaluate the fact, that some CI/CD setups for OpenShift may spoil the most simple type of testing a developer uses: Just running the software locally - in OpenShift.
This report is about the experience, I’ve made with Arch Linux as the operating system for a developers workstation. You’ll be introduced into the concepts of Arch Linux, followed by a introduction into the main tasks such as package installation and OS maintenance. At the end, I’ll discuss why I think that Arch Linux is a great OS for developers, and finish with a conclusion.
Prometheus is a popular monitoring tool based on time series data. One of the strengths of Prometheus is its deep integration with Kubernetes. Kubernetes components provide Prometheus metrics out of the box, and Prometheus’s service discovery integrates well with dynamic deployments in Kubernetes.
There are multiple ways how to set up Prometheus in a Kubernetes cluster. There’s an official Prometheus Docker image, so you could use that and create the Kubernetes YAML files from scratch (which according to Joe Beda is not totally crazy). There is also a helm chart. And there is the Prometheus Operator, which is built on top of the CoreOS operator framework.
Kubeadm is a basic toolkit that helps you bootstrap a simple Kubernetes cluster. It is intended as a basis for higher-level deployment tools, like Ansible playbooks. A typical Kubernetes cluster set-up with
kubeadm consists of a single Kubernetes master, which is the machine coordinating the cluster, and multiple Kubernetes nodes, which are the machines running the actual workload.
Dealing with node failure is simple: When a node fails, the master will detect the failure and re-schedule the workload to other nodes. To get back to the desired number of nodes, you can simply create a new node and add it to the cluster. In order to add a new node to an existing cluster, you first create a token on the master with
kubeadm token create, then you use that token on the new node to join the cluster with
Dealing with master failure is more complicated. Good news is: Master failure is not as bad as it sounds. The cluster and all workloads will continue running with exactly the same configuration as before the failure. Applications running in the Kubernetes cluster will still be usable. However, it will not be possible to create new deployments or to recover from node failures without the master.
This post shows how to backup and restore a Kubernetes master in a
Docker containers running in Kubernetes have an ephemeral file system: Once a container is terminated, all files are gone. In order to store persistent data in Kubernetes, you need to mount a Persistent Volume into your container. Kubernetes has built-in support for network filesystems found in the most common cloud providers, like Amazon’s EBS, Microsoft’s Azure disk, etc. However, some cloud hosting services, like the Hetzner cloud, provide network storage using the CIFS (SMB, Samba, Windows Share) protocol, which is not natively supported in Kubernetes.
Fortunately, Kubernetes provides Flexvolume, which is a plugin mechanism enabling users to write their own drivers. There are a few flexvolume drivers for CIFS out there, but for different reasons none of them seemed to work for me. So I wrote my own, which can be found on github.com/fstab/cifs.
This blog post shows how to use the
fstab/cifs plugin for mounting CIFS volumes in Kubernetes.
ConSol CM brings BPM to a CRM system. In-house ConSol CM is used to process cases of a wide range of types. Amongst others it also maps the sales process. For that purpose a new sales case is created automatically or manually every time a sales opportunity or lead comes up. To these cases, information can be added concerning the communication with the customer, the origin of the opportunities and others.
Within a research and development project the scope was to predict the success for open sales cases, using machine learning algorithms. This way, sales employees would know already in an early stage if the opportunity most probably will be successful or how to adapt their strategy during the sales process to increase the chances for success.
Docker Headless VNC Container 1.3.0 has been released today. The different Docker images contains a complete VNC based, headless UI environment for testautomation like Sakuli does or simply for web browsing and temporary work in a throw-away UI container. The functionality is pretty near to a VM based image, but can be started in seconds instead of minutes. Each Docker image has therefore installed the following components:
When you are developing software, you will most likely stumble upon situations where you must perform frequent, but minor, code changes. Changes that do not alter your software’s basic functionality, changes so simple that from a developer’s perspective are more like a different configuration for your code but are still a bit too complex to use a simple configuration file.
In this article I will show you how to use Apache FreeMarker to implement dynamic and complex configurations in Java projects that can be configured from outside the application.
Database communication is an essential part of many applications, when persistent data storage is required. May it be orders, customer data, product recommendations or product information, if persistent storage is in place, the data contains a certain business value. Therefore it’s important that your software handles your persistent storage the right way.
In this blog post you’ll learn how to test your database communication using Citrus.
At this year’s FOSDEM conference I did a 30 minutes presentation on Monitoring Legacy Java Applications with Prometheus. The talk gives an overview of some of the options you have for monitoring Java applications with Prometheus when you cannot modify the application’s source code:
The video is available below.