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: ...

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: ...

This is Chapter 1 of the System Design series. Architecture reviews and design discussions keep coming back to the same vocabulary regardless of what’s being built. I keep this list so I’m reasoning from consistent definitions each time, not re-deriving the same trade-offs from scratch. Core concepts Systems Always Lose Consistency - CAP Is Fundamental Scalability Availability Latency Consistency CAP Idempotency Fault tolerance 1. Scalability Vertical scaling (bigger machine) buys time but hits a ceiling fast and creates a single point of failure. Horizontal scaling (more machines) is the default for anything expected to grow past a single box, at the cost of needing to handle state, coordination, and partial failure across nodes. 2. Availability Usually expressed in nines: ...

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: ...

This is Chapter 1 of the DevSecOps Guardrails series. I wired cdk-nag in as the first guardrail in this series because it is CDK-native: it runs against the construct tree at synth time and blocks the build on any rule violation - before a changeset is created, before any AWS API call is made. It sees the construct level, not just the synthesised template, which means it can catch things cfn-lint cannot. ...