Running Kubernetes-IN-Docker

The fastest way to launch a Kubernetes cluster locally !!!

Kubernetes in Docker

kind is a tool for running local Kubernetes clusters using Docker containers. It was primarily designed for testing Kubernetes itself, but may be used for local development or CI.

Pre-requisites

• Docker installed on your local machine
• Kind binaries (follow the installation instructions)

Deploying k8s Cluster

Let’s deploy a k8s cluster with 1 x controller node and 3 x worker nodes.

• First, create a cluster config file kind_cluster_config.yaml

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  extraPortMappings:
    - hostPort: 30080
      containerPort: 30080
- role: worker
- role: worker
- role: worker

• Let’s create a k8s cluster named cluster-1

kind create cluster --image kindest/node:v1.17.0 --name cluster-1 --config kind_cluster_config.yaml

The output of the cluster creation is shown below

Once the cluster creation is done, we need to set kubernetes context to interact with the cluster

kubectl cluster-info --context kind-cluster-1
kubectl get nodes
kubectl get pods -n kube-system

• You can verify that all k8s nodes are running in Docker containers by issuing docker ps command

Deploying Application on Kind cluster

• Create an app.yaml file

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-k8s-deployment
  labels:
    app: hello-k8s
spec:
  replicas: 3
  selector:
    matchLabels:
      app: hello-k8s
  template:
    metadata:
      name: hello-k8s-pod
      labels:
        app: hello-k8s
    spec:
      containers:
        - name: node-hello
          image: gcr.io/google-samples/node-hello:1.0
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: hello-k8s-service
  labels:
    app: hello-k8s
spec:
  type: NodePort
  ports:
    - name: hello-k8s-service
      port: 8080
      targetPort: 8080
      nodePort: 30080
  selector:
    app: hello-k8s

• Create a new namespace (not mandatory)

kubectl create ns hello-k8s

• Deploy the app

kubectl -n hello-k8s create -f app.yaml
kubectl -n hello-k8s get all

• Browse your app on either CLI or Browser

curl http://localhost:30080

That’s All Folks :

KinD makes is dead simple and efficient to run a k8s cluster locally, I believe kind could be a minikube killer and worth giving a try.