Intro to Kind Kubernetes (Local Kubernetes Development) - Part 2
To make the process of building more complex Kind infra, Kind provides configuration files which can be passed to the kind create CLI.
This example will be walking through creating a dev ready Kind cluster for web app development which will allow hosting a Frontend/Backend/DB with Ingress resources.
Setting up cluster
The below command will setup a 3 node cluster.
echo '''
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
kubeadmConfigPatches:
- |
kind: InitConfiguration
nodeRegistration:
kubeletExtraArgs:
node-labels: "ingress-ready=true"
extraPortMappings:
- containerPort: 80
hostPort: 80
protocol: TCP
- containerPort: 443
hostPort: 443
protocol: TCP
- role: worker
- role: worker
''' | kind create cluster --config=-
Creating cluster "kind" ...
✓ Ensuring node image (kindest/node:v1.19.1) 🖼
✓ Preparing nodes 📦
✓ Writing configuration 📜
✓ Starting control-plane 🕹️
✓ Installing CNI 🔌
✓ Installing StorageClass 💾
✓ Joining worker nodes 🚜
You can check the cluster node status by running
kubectl get nodes
NAME STATUS ROLES AGE VERSION
kind-control-plane Ready master 5m8s v1.19.1
kind-worker Ready <none> 4m38s v1.19.1
kind-worker2 Ready <none> 4m38s v1.19.1
Configure an Nginx ingress controller
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/kind/deploy.yaml
tic/provider/kind/deploy.yaml
namespace/ingress-nginx created
serviceaccount/ingress-nginx created
configmap/ingress-nginx-controller created
clusterrole.rbac.authorization.k8s.io/ingress-nginx created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx created
role.rbac.authorization.k8s.io/ingress-nginx created
rolebinding.rbac.authorization.k8s.io/ingress-nginx created
service/ingress-nginx-controller-admission created
service/ingress-nginx-controller created
deployment.apps/ingress-nginx-controller created
validatingwebhookconfiguration.admissionregistration.k8s.io/ingress-nginx-admission created
serviceaccount/ingress-nginx-admission created
clusterrole.rbac.authorization.k8s.io/ingress-nginx-admission created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
role.rbac.authorization.k8s.io/ingress-nginx-admission created
rolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
job.batch/ingress-nginx-admission-create created
job.batch/ingress-nginx-admission-patch created
Run this command to wait until ingress controller is ready (espeshally important in CI test environments)
kubectl wait --namespace ingress-nginx \
--for=condition=ready pod \
--selector=app.kubernetes.io/component=controller \
--timeout=90s
pod/ingress-nginx-controller-55bc59c885-8kcp4 condition met
Deploy example app to test ingress deploy. This deploys two pods & services, with an ingress that directs traffic between the two services.
kubectl apply -f https://kind.sigs.k8s.io/examples/ingress/usage.yaml
pod/foo-app created
service/foo-service created
pod/bar-app created
service/bar-service created
You can view these services by accessing:
In order to demonstrate the end to end workflow, this guide will walk through a very simple app deployment. This app will just return the number of requests recieved. The container will be built locally & deployed in Kind. Network ingress will come through the ingress setup previously.
The first step is to create a docker image with the required dependencies. For simplicity in the demo, I’ve included the docker file inline in the docker build command below.
echo '''
FROM python
RUN pip install flask requests''' | docker build -t k8s_demo:local -f - .
To push the docker image to Kind, run kind load docker-image k8s_demo:local. This makes the docker image available in the Kind k8s cluster.
Then, run the following command to deploy a container with the config to Kind:
echo '''
apiVersion: v1
kind: ConfigMap
metadata:
name: demo-api
data:
run.py: |
from flask import Flask
app = Flask(__name__)
num_requests = 0
@app.route("/api")
def count():
global num_requests
num_requests += 1
return(str(num_requests))
if __name__ == "__main__":
app.run(host="0.0.0.0")
---
kind: Pod
apiVersion: v1
metadata:
name: demo
labels:
app: demo
spec:
containers:
- name: demo
image: k8s_demo:local
command: ["python"]
args: [ "/app/run.py" ]
imagePullPolicy: IfNotPresent
volumeMounts:
- name: config
mountPath: /app
volumes:
- name: config
configMap:
name: demo-api
---
kind: Service
apiVersion: v1
metadata:
name: demo
spec:
selector:
app: demo
ports:
- port: 5000
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: demo
spec:
rules:
- http:
paths:
- path: /api
pathType: Exact
backend:
service:
name: demo
port:
number: 5000
''' | kubectl apply -f -
configmap/demo-api created
pod/demo created
service/demo created
ingress.networking.k8s.io/demo created
You can view the resources created by running kubectl describe <either ingress,pod,or configmap>.
Once the pod starts, you can view the app by opening: http://localhost/api which returns the request count.
Finally, to cleanup & delete the cluster, run kind delete cluster
Resources: