KinD -- Kubernetes in Docker

Prerequisites

• Docker
• Kubectl
• Terraform (optional)
• KIND

Kind Installation

Single command to kind on ubuntu

for the ubuntu vms --just run

make setup-kind

Mac

brew install kind

Windows

choco install kind

** Troubleshooting Port 80 problem

• If you are unable to create the cluster with the kind-setup/config.yml due to port 80 being in use. Check and kill the process running on it

• It could also be nginx running locally or you are running some webserver on your machine which operates on port 80.

Help

kind --help

Create Cluster

make kind-create-cluster

Verify cluster is UP

kubectl cluster-info --context kind-demo-cluster

Setup Nginx Ingress

make kind-ingress-setup

check pods

kubectl -n ingress-nginx get pods
kubectl -n ingress-nginx get pods -w

Setup Services Loadbalancer

Check your address pool

docker network inspect -f '{{.IPAM.Config}}' kind

The output will contain a cidr such as 172.18.0.0/16. We want our loadbalancer IP range to come from this subclass. We can configure metallb, for instance, to use 172.18.255.200 to 172.18.255.250 by creating the configmap.

Now apply the setup

make create-loadbalancer

make lb-address-pool

Test Loadbalancer or app deployments (optional)

Let's deploy nginx which has a service, deployment and an ingress. We will get the loadbalancer's IP and then test that in the browser or using any commandline utility like curl. You should see the default nginx page.

make demo-nginx-setup

testing Visit the loadbalancer ip to see your service running.

OR

Run:

curl <lb-ip>
curl 172.18.255.200

Using the hostname (Linux)

We’ll need to get the IP address of our kind node’s Docker container first by running:

kubectl get svc/nginx-service -o=jsonpath='{.status.loadBalancer.ingress[0].ip}'

Then add an entry to /etc/hosts with the IP address found that looks like:

172.18.255.200 test.kalkulus.local

Resolving hostname with Docker (All Machines)

The previous step work, but require working with the host system and are limited to Linux. We can instead create a Docker container. We can leverage docker run’s --add-host argument to add an entry to the container’s /etc/hosts file.

docker run \
  --add-host test.kalkulus.local:172.18.255.200 \
  --net kind \
  --rm \
  curlimages/curl:7.71.0 test.kalkulus.local

Port-forward a pod to check if it works

kubectl port-forward po/demo-fastapi-6678bbbd54-5t97r 8000:8000 -n backend

Build Image

This builds the image and push it to the KinD cluster.

make image-build

Deploy Kubernetes Manifests

make demo-fastapi-deploy-manifests

Check deployment status

make demo-fastapi-status

Destroy KinD Cluster

make kind-destroy-cluster