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Quotas, limits and limit-ranges

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...

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Scaling applications - Rollout, Scale and Auto-Scale Deployments

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...

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ServiceAccounts and SCCs - Running pods with more permission's

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...

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Creating and Using Secrets in OpenShift

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)...

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Creating my EX280 page on Jekyll

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...

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Taints and Tolerations - Can't Pods and Nodes just get along?

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...

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ConfigMaps - Setting ConfigMaps from the oc CLI

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...

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Installing vim-plug on macOS

vim-plug is a VIM plug-in manager to install themes and other plug-ins in VIM. It’s the most populair one at the moment. Installation To install vim-plug you can go over to https://github.com/junegunn/vim-plug and run the following command: $ curl -fLo ~/.vim/autoload/plug.vim --create-dirs \ https://raw.githubusercontent.com/junegunn/vim-p...

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