CPU and Memory Management on Kubernetes with Cgroupsv2 In this post I’ll try to explain how CPU and Memory management works under the hood on Kubernetes. If you ever wondered what happens when you set requests and limits for your pods, keep reading! Attention This is the result of my exploratory work around cgroupsv2 and their application to Kubernetes. Even though I tried really hard to make sure the information in this post is accurate, I’m far from being an expert on the topic and some information may not be 100% accurate....

Exposing multiple Kubernetes clusters with a single load balancer and a single public IP My colleague Alberto Losada and I have been working on a lab lately. The lab is composed of three OpenShift clusters on VMs, these VMs are deployed on an isolated libvirt network, which means that we cannot access them from outside the hypervisor. In order to solve this issue, we wanted to expose the three clusters using the public IP available in the hypervisor....

Enhanced Version and Build Information for your Go programs with ldflags In the previous post we show how to create a simple CLI in Go with Cobra. I received a suggestion from one of my colleagues, Andrew Block. He suggested complementing that post with the use of ldflags at build time in order to define specific information to a specific build like build time, git commit, etc. Andy is also running a blog, go check it out!...

Writing CLIs in Go using Cobra A few months ago, I was working with my colleague Alberto in a CLI. The language of choice was Go and I manage to learn a thing or two. In today’s post we will see a very basic skeleton for a CLI written in Go. This will certainly help me in the future as a template for the next CLI, and maybe it helps you too!...

User Certificates in OpenShift 4 Attention The information described in this blog post may not be a supported configuration for OpenShift 4. Please, refer to the official docs for supported documentation. In this blog we will see how we can create OpenShift Users using client certificates and how to configure the API Server, so we can create client certificates using custom CAs. The information described in this blog was last tested with OpenShift 4....