Kubernetes

This post is a continuation of https://maarten.gent/posts/debugging/debug-complex-containerized-application/ A quick recap: we moved a complex 3-pod containerized application from OKD (Openshift) 3 to 4 and hit a network issue. Some lengthy debugging was required but we felt confident we could move our biggest customers to the new platform once resolved. Set the stage The weekend is family time (or blog time) but not this time: a switch died in the datacenter which brought the storage down of the old OKD cluster....

The story of how we resolved a hard to debug issue migrating a complex containerized application to a Kubernetes cluster. I learned some lessons that might be useful for you too. Problem statement Application Sorry for the vague description but the application involves three pods. One pod contains a container running an OpenVPN (client) process. Users access the application using a web interface and traffic flows back and forth through an VPN tunnel accessing a service running in a restricted network on the other end of the tunnel....

Kustomize is my favorite tool to manage the bunch of YAML we need to manage operating our clusters and applications. Since it is integrated in kubectl and oc, it is possible to apply a config to your cluster using one command. Or if you like Gitops, ArgoCD can sync your kustomize layer(s) stored in git automatically. A project usually consists of a base layer and a few subsidiary layers that are customized versions of the base....

OKD is the open source equivalent of RedHat’s Openshift product. Openshift is an opiniated patched Kubernetes flavour, marketing itself as more developer oriented and more secure. I always forget what the acronym OKD stands for, so Google it yourself it you like to know. Changing jobs about a year ago, I inherited some long running clusters and the internal work flow using and operating the platforms. I had about 4 years of experience operating and developing on ‘vanilla’ Kubernetes before....

Warning: work in progress. In this blog post you will learn how easy it is to setup object storage (cfr. AWS S3) using the Rook Ceph operator in Kubernetes. The Rook object storage quickstart is a good resource (https://rook.io/docs/rook/v1.9/ceph-object.html ) but I experienced a few bumps on the road, and I learned how easy it is to expose the storage with an user friendly web interface. Requirements The other day we needed a storage solution with following requirements:...