Articles
Deploy OpenShift Single Node in KVM
Starting with version 4.8, OpenShift can now officially be installed on a single virtual machine (instead of three). This effectively lowers the resources requirements and open up new possibilities for home labs or developer workstations. This article explores how to deploy OpenShift Single Node (SNO) using KVM on your Fedora workstation. Continuer la lecture
Consistent DNS name resolution for virtual machines and containers
When developing on microservices, developers need to run a mix of software. Some of them running in containers, others in virtual machines, some others in the cloud and the rest on the developer’s workstation. Microservices having a lot of connections between themselves in addition to technologies such as TLS or OpenID Connect implies DNS names to be consistent. Consistent DNS names means that no matter if a client on the developer workstation, on a VM or on a container, trying to reach a server on the developer workstation, on a VM or on a container, the server DNS name must always be the same. This article explains how to setup a developer workstation on Fedora, with Libvirt VMs and Podman containers and achieve consistent DNS name resolution. Continuer la lecture
Sauvegarder la configuration de ses EdgeSwitch et EdgeRouter avec Ansible
J’utilise des équipements de marque Ubiquiti dans mon réseau informatique à la maison: un EdgeSwitch et un EdgeRouter. Et jusqu’à présent, je n’avais pas mis en place de moyen simple et automatisé pour sauvegarder leur configuration. C’est désormais chose faite avec ce playbook Ansible qui me sauvegarde la configuration des deux équipements et me l’enregistre dans un entrepôt Git. Continuer la lecture
How to run performance tests with K6, Prometheus and Grafana
K6 is a novel performance testing tool written in Go, using plain Javascript for the test definition and presenting the test results through Grafana. An existing article written in 2018 explains how to setup K6 with InfluxDB and Grafana, however Prometheus gained popularity over InfluxDB since then. Proper integration of K6 with Prometheus is a clear lack identified by the community. Here I explain how to integrate K6 with Prometheus using the existing StatsD support in K6, present the Grafana dashboard I built, and show how to use it. This integration fills a gap and provides a quick win for companies already using Prometheus. Continuer la lecture
Implémenter le motif de conception 'Strangler Fig' dans OpenShift
Le motif de conception Strangler Fig a été documenté par Martin Fowler en 2004. Il fait référence à un arbre nommé le “figuier étrangleur” qui s’appuie sur son hôte pour ses premières années de vie, jusqu’à ce que ses racines touchent le sol. Il peut ainsi se nourrir et grandir de manière autonome. Son hôte sert alors de support et finit par mourir “étranglé”. C’est une analogie avec la ré-ingénierie d’un système en production: les composants d’un monolithe sont réécrits un à un, sous forme de micro-services, à coté du système existant. Les composants du monolithe sont alors remplacés au fil de l’eau par leur équivalent micro-service. Une fois tous les composants du monolithe remplacés, il peut alors être décommissionné. La question qui m’a été posée est: est-il possible d’implémenter ce motif à l’aide des outils et fonctions d’OpenShift ? Continuer la lecture
Build your own distribution based on Fedora CoreOS
Fedora CoreOS is a new Linux distribution from the Fedora Project that features filesystem immutability (you cannot change the system while it is running) and atomic upgrades (you cannot break your system if there is a crash or power loss during the upgrade). Upon installation, Fedora CoreOS (FCOS) can be tailored to your needs using Ignition files. Once installed, you can install RPMs, tweak configuration files, etc. This article tries to explore Fedora CoreOS customizability one step further by building your own distribution based on Fedora CoreOS. The idea would be to have everything wired in the Operating System image and minimal configuration in the Ignition file. Continuer la lecture
Use JMeter to assess software performances
One of my side projects (the Telegram Photo Bot), have some performance issues that I will have to tackle. I could have jumped into the code and changed something, hoping it will improve performances. But that would be ineffective and unprofessional. So, I decided to have an honest measure of the current performances as well as a reproducible setup to have consistent measures over time. Continuer la lecture
A cleanup playbook for 3scale
If you are running integration tests embedding 3scale or are doing a lot of 3scale demos, you might sooner or later have plenty of services declared in the 3scale Admin console, which could reveal difficult to work with. And with the new feature named API-as-a-Product, there are now Backends and Products to delete, making the cleanup by hand a bit tedious. This article explains how to cleanup a 3scale tenant using Ansible. Continuer la lecture
Install Kubernetes operators in OpenShift using only the CLI
OpenShift 4 went all-in on Kubernetes operators: they are used for installation of the platform itself but also to install databases, middlewares, etc. There are more and more operators available on the Operator Hub. Most software now provide an operator and describe how to use it. Nevertheless, almost every software documentation I read so far, includes the steps to install the operator using the nice GUI of OpenShift 4. But since my OpenShift environments are provisioned by a playbook, I want to be able to install operators using the CLI only! Continuer la lecture
Secure your OpenShift 4 cluster with OpenID Connect authentication
OpenShift, starting with the version 4, is installed with a temporary administrator account, kubeadmin. When searching for a definitive solution, it might be tempting to go for the very classical “login and password” prompt, backed by an htpasswd file. But this is yet another password to remember! OpenShift can handle the OpenID Connect protocol and thus offers Single Sign On to its users. No additional password to remember: you can login to the OpenShift console with your Google Account for instance. Continuer la lecture