From 964a325fcdd9982e15ebcc8ad5b2ae188fe77665 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Petazzoni?= <jerome.petazzoni@gmail.com>
Date: Tue, 28 Oct 2025 21:44:09 +0100
Subject: [PATCH] =?UTF-8?q?=E2=9E=95=EF=B8=8F=20Add=20chapter=20about=20co?=
 =?UTF-8?q?despaces=20and=20dev=20clusters?=
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+# Codespaces
+
+- We're going to use GitHub Codespaces to get a Docker/Kubernetes lab
+
+- This can take a few minutes (because of image builds, downloads...)
+
+- Let's do it now, so that it's ready when we'll need it!
+
+---
+
+## Creating a codespace
+
+- Click on [that link][codespaces-new] then click `Create codespace`
+
+  (feel free to pick a region closer to you!)
+
+- Another way to create the codespace:
+
+  - go to https://github.com/jpetazzo/container.training
+
+  - click on the green `<> Code v` button
+
+  - click on the green `Create codespace on main` button
+
+- If you use an IDE that supports devcontainers, you can also use that instead
+
+  (example: VScode; but today, please just use codespaces for simplicity :))
+
+[codespaces-new]: https://github.com/codespaces/new?hide_repo_select=true&ref=main&repo=37004081&skip_quickstart=true
+
+---
+
+## Troubleshooting
+
+- If it takes more than a couple of minutes or says "Oh no, it looks like you are offline":
+
+  disable "enhanced tracking protection" and/or uBlock origin and reload the page
+
+---
+
+## KinD
+
+- The Codespaces environment runs Docker, and is loaded with many tools
+
+- We still need to create a Kubernetes cluster
+
+- We're going to use KinD to do that
+
+  (but we could also use minikube, k3d...)
+
+.lab[
+
+```bash
+
+- Create a Kubernetes cluster with KinD:
+  ```bash
+  kind create cluster
+  ```
+
+]
+
+- Note: if you have a machine running [Docker][install-docker] or [Podman][install-podman], you can [install KinD][install-kind] and then run `kind create cluster`!
+
+[install-docker]: https://www.docker.com/get-started/
+[install-podman]: https://podman.io/get-started
+[install-kind]: https://kind.sigs.k8s.io/docs/user/quick-start/#installing-from-release-binaries
+
+---
+
+## Checking that our cluster works
+
+- One of the most basic commands we can do is to list the nodes of the cluster
+
+  (with KinD, by default, we get a cluster with one single node)
+
+.lab[
+
+- List the nodes (well, the node) of the cluster:
+  ```bash
+  kubectl get nodes
+  ```
+
+]
+
+- If you deployed the cluster with KinD, you can also run `docker ps`
+
+  (what do we see?)
+
+---
+
+## Dev clusters vs "real" clusters
+
+- With KinD, minikube, and other dev clusters, we can:
+
+  - run containers on a one-node cluster
+
+  - use Kubernetes tools like `kubectl`, `k9s`, `helm`, and many more
+  
+  - create all kinds of Kubernetes resources (Deployments, Services...)
+
+  - install operators, webhooks, and all sorts of Kubernetes extensions
+
+  - deploy things like Prometheus, Grafana, Argo, Flux
+
+  - we can even prototype persistent applications (databases, queues...)
+
+- So, what *cannot* we do?
+
+---
+
+## Limitations
+
+- We cannot expose containers to the outside world like we'd do on a normal cluster
+
+  (e.g. with a *`LoadBalancer Service`*)
+
+- It's running on our local machine
+
+  (so we're limited in terms of RAM, CPU, storage...)
+
+- Our dev cluster typically has a single node
+
+  (making it harder to experiment with DaemonSets, taints, tolerations, affinity...)
+
+- Metrics might be off
+
+  (since the cluster isn't the only thing running on the machine)