Home Original page

GitHub - joelnotified/kubernetes-demo

Setup

Step 1. Make sure you have kubernetes locally

Use the local version of Kubernetes that comes with Docker desktop. See the link for installation instructions. It can be quite resource heavy so you should disable it once you're done.

There are other options like kind, minikube, k3s if you prefer.

Step 2. Connect to the cluster using kubectl

Make sure you have kubectl installed. It should be installed as part of Docker under C:\Program Files\Docker\Docker\resources\bin\kubectl.exe. If you can't type kubectl in a terminal window, then you need to add that path to the system environment variable called PATH.

  • kubectl config get-contexts should list all the "contexts" (the clusters) you have access to. The docker-desktop cluster should be there
  • kubectl config use-context docker-desktop should connect you to the local cluster
  • Make sure you can access it by running kubectl get pods -A (list all pods in all namespaces)

Step 3. Connect to the cluster using Lens

You might also want to connect to the cluster using Lens, so that you get a better overview of what's going on. The cluster should be listed in Lens and you should be able to connect to it.

Step 4. Create a personal access token

  1. In order to run Flux locally, you need to create a personal access token in GitHub: https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token.
  2. $env:GITHUB_TOKEN='<your token>'
  3. $env:GITHUB_USER='<your username>'

Step 5. Install Flux CLI

You're going to need the Flux CLI, install it from here: https://fluxcd.io/flux/installation/#install-the-flux-cli (again, Chocolatey is an easy way for Windows).

Simple kube apply and kustomize

Create a namespace

  1. kubectl get namespaces will list the existing namespaces
  2. cd manifests
  3. kubectl apply -f namespace.yaml will tell kubernetes to create the namespace defined in the file.
  4. kubectl get namespaces will list the new namespace

Create a Pod

We actually create a Deployment, which is responsible of keeping one or more replicas of a pod alive.

  1. kubectl apply -f deployment.yaml
  2. kubectl get pods -n whoami list the pods in the whoami namespace
  3. If you delete a pod, the deployment will make sure a new replica is created. kubectl delete pod -n whoami <name_of_pod>

A Service

Create a Service which we can use to access the pods in a load balanced way.

  1. kubectl apply -f service.yaml
  2. kubectl get services -n whoami to make sure the service is created. You can see that it has a ClusterIP but no ExternalIP. This means that you cannot access this service from outside the cluster.
  3. A way of accessing the service is to do a port-forward. That will map a port on your local computer, to a port on the service. This isn't something you do other than in debugging purposes. kubectl port-forward -n whoami svc/whoami 8080:80 will let you access the service from http://localhost:8080/ on your local computer.
  4. Press ctrl+c to abort port forwarding

An Ingress Controller

In order to access a service (and indirectly a pod) from outside the cluster, we need an Ingress Controller. The one we use is Traefik.

Setup Traefik

  1. cd traefik
  2. kubectl apply -f 00-role.yaml -f 00-account.yaml -f 01-role-binding.yaml -f 02-traefik.yaml -f 02-traefik-services.yaml
  3. http://localhost:8080/dashboard/#/ should show you the Traefik dashboard
  4. http://localhost:80 will give you a 404 (from Traefik)

Setup an Ingress resource

  1. kubectl apply -f 03-whoami.yaml -f 03-whoami-services.yaml -f 04-whoami-ingress.yaml
  2. http://localhost:80

Kustomize

  1. Start by deleting the previous stuff kubectl delete -f 00-role.yaml -f 00-account.yaml -f 01-role-binding.yaml -f 02-traefik.yaml -f 02-traefik-services.yaml -f 03-whoami.yaml -f 03-whoami-services.yaml -f 04-whoami-ingress.yaml
  2. kubectl kustomize will use kustomize to merge the files into one.
  3. kubectl apply -k ./

Doing GitOps using Flux

Flux is a tool that helps us do "GitOps". That means that we can have a desired state in git, and it will be Flux's job to make sure that state is reconciled in the cluster.

Flux is running as a pod in the cluster, listening for changes in the git repository while also making sure the cluster matches what's in git.

  1. Make sure you're good to go: flux check --pre
  2. Install Flux in the cluster, and create a new personal reposoty flux will sync against flux bootstrap github --owner=$env:GITHUB_USER --repository=flux-demo --branch=main --path=./clusters/my-cluster --personal
  3. Check Flux installation kubectl get pods -n flux-system
  4. Clone your new repo: git clone https://github.com/$env:GITHUB_USER/fleet-infra and open it in an editor