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I have written about using Taints and Tolerations to prevent pods from running on certain (tainted) nodes and there is some influence on scheduling that we can exert using Limits and Requests. But if we really want to control pod placement we have to look no further than Node/Pod Affinity and Anti-Affinity. This allows you to specify nodes that...

In this post we will be diving in to quotas and limits. Quotas and limits can be used to allocate, limit en reserve resources within your cluster for one or multiple namepaces and can limit the usage of CPU and Memory for workloads. Limits can also be used to gurante (by reserving) resources for your workloads. Understanding and using quotas and...

This post is gonna be a bit bigger broader then what is requested on the EX280 exam objectives. In this post we will have a look at: Controlling roll-out of pods (manually rolling out or back a deployment) Scaling Deployments on the command-line Creating a auto scaler for a deployment on the command-line Now, apart from the scaling bein...

In this blog we will take a look at SCC permissions that are needed to run a pod with escalated permissions and how to use a serviceaccount (sa) to run such a pod or deployment. Small thing: I use the term pod and container in this post but I’m referring to the same idea. In Openshift and Kubernetes we talk about pods being the smallest unit of...

Creating Secrets (like creating ConfigMaps) is a vital part of Managing OpenShift workloads and is an exam objectives of the EX280 exam. Knowing how they work and how to configure them (from the command-line) will give you a better understanding of Secrets. Secrets, how do they work Secrets provide information (like config files or credentials)...

As you might have notices I use Jekyll for this blog hosted on GitHub. I might do a post later on how I use it and how I set it up. For now, all you need to know is that Jekyll turns .md(markdown) file in to a blog. This happens using GitHub actions and builds my blog from source when I commit to main. Jekyll support some dynamic code to genera...

During my study for EX280 I found Taints and Tolerations very hard to understand. This is because Taints and Tolerations flip the scheduling of pods the other way around. What I mean by this is the following. Traditionally you would specify on a server what the server would run and what not. But in OpenShift this is flipped around. Instead of cr...

While preparing for EX280 I learned a lot about using the CLI to configure Openshift resources. It’s always great learning to configure this stuff from the CLI because it gives you so much power and (In my opinion) a lot more understanding about how things work because you need to viluazie what you are doing in your head. Also: “Writing is think...