Kubernetes

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Kubernetes Fundamentals - Series Overview

The Kubernetes Fundamentals domain in my KCNA study notes covers the architecture and core resources at a conceptual level - this series goes one layer deeper, into the actual objects and kubectl commands behind those concepts. This series is the companion to Docker Fundamentals, one level up the stack - it assumes that Docker layer (containers, images, the container runtime) and builds the Kubernetes object model on top of it. A throwaway cluster (minikube, kind, or a Killercoda sandbox) is the only prerequisite; none of this needs a managed cloud Kubernetes service to follow along. The series Chapter 1 - Kubernetes Architecture The control plane and node components - kube-apiserver, etcd, kubelet, the controller manager, and the scheduler - and what each is actually responsible for. ...

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Kubernetes and Cloud Native Associate (KCNA) Study Notes

I sat the Kubernetes and Cloud Native Associate (KCNA) and passed. KCNA is the entry-level CNCF certification - it covers Kubernetes fundamentals and the wider cloud native landscape at a conceptual level, and it is the natural first step before the hands-on CKA, CKAD, and CKS exams. It is a multiple-choice exam, so it rewards knowing what the pieces are and how they relate, not hands-on kubectl skill. If you already work with Kubernetes, a lot of this will be familiar, so calibrate the prep to what you already know. ...

Kubernetes Fundamentals - kubectl and Pods

This is Chapter 2 of the Kubernetes Fundamentals series. Installing kubectl Install kubectl before a local cluster tool like minikube - minikube depends on it being present. kubectl reference kubectl Quick Reference Install kubectl - official install steps per OS Confirm kubectl can reach the cluster: kubectl cluster-info List the nodes in it: kubectl get nodes Check a node’s details - capacity, conditions, and what’s running on it: kubectl describe nodes Output formatting kubectl [command] [TYPE] [NAME] -o <format> controls how a command’s output is rendered: ...

Kubernetes Fundamentals - Architecture

This is Chapter 1 of the Kubernetes Fundamentals series. Nodes and clusters A node (sometimes called a minion) is a worker machine in Kubernetes - a collection of Pods runs on it. Multiple nodes together form a cluster. One node in that cluster is the master node - it watches over the worker nodes, orchestrates containers across them, and is where Kubernetes itself is installed. The five components Installing Kubernetes means installing five components. A mnemonic worth keeping: Api-server, Etcd, Kubelet, Controller, Scheduler: ...

Docker Fundamentals

The Kubernetes Fundamentals domain in my KCNA study notes assumes container runtime knowledge going in - Docker, in practice, since it’s still the most common way people get there. The Kubernetes Fundamentals series is the companion to this post, one level up the stack. Prerequisites WSL2 with Ubuntu on Windows, or native Linux/macOS sudo access on the machine you’re installing on A Docker Hub account if you want to push images Installing Docker On WSL2/Ubuntu, install Docker Engine directly rather than Docker Desktop - run this from your home directory in the WSL2 shell: ...