Pre-requisites

• Ubuntu OS (Xenial or later)

• sudo privileges

• Internet access

• t2.medium instance type or higher

Docker Installation on both Master and Worker Node

To prepare both the master and worker nodes for Kubeadm, follow the Sample Command run on the master node

Switch to superuser mode:

sudo su

Update the package repository:

apt update -y

Install Docker and start the service:

Add Google's GPG key and repository for Kubernetes:

curl -fsSL "https://packages.cloud.google.com/apt/doc/apt-key.gpg" | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/kubernetes-archive-keyring.gpg 
echo 'deb https://packages.cloud.google.com/apt kubernetes-xenial main' > /etc/apt/sources.list.d/kubernetes.list

Update the repository again:

apt update -y

Install specific versions of Kubeadm, Kubectl, and Kubelet:

apt install kubeadm=1.20.0-00 kubectl=1.20.0-00 kubelet=1.20.0-00 -y

Follow the same commands on the worker node as well. By executing these commands on both the master and worker nodes, you'll ensure they are ready to work with Kubeadm.

Here are the steps and commands for initializing the Kubernetes master node, setting up worker nodes, and verifying the cluster connection:

Master Node Setup

1. Initialize the Kubernetes master node:

sudo su
kubeadm init

Set up local kubeconfig (both for the root user and normal user)

mkdir -p $HOME/.kube 
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Apply the Weave network:

kubectl apply -f https://github.com/weaveworks/weave/releases/download/v2.8.1/weave-daemonset-k8s.yaml

Generate a token for worker nodes to join:

kubeadm token create --print-join-command

Expose port 6443 in the Security group for the Worker to connect to the Master Node.

Worker Node Setup

Run the following commands on the worker node to reset the checks so it can't assign as Master

sudo su
kubeadm reset pre-flight checks

Paste the join command on Worker Node which you want to join to Master - You received from the Master node and append --v=5 at the end.

After successful join, verify the cluster connection by running the command in the Master Node :

kubectl get nodes

Optional: Labeling Nodes

If you want to label worker nodes, you can use the following command:

kubectl label node <node-name> node-role.kubernetes.io/worker=worker

Optional: Test a Demo Pod

If you want to test a demo pod, you can use the following command on Master:

kubectl run hello-world-pod --image=busybox --restart=Never --command -- sh -c "echo 'Hello, World' && sleep 3600"

By following these steps, you'll successfully initialize the master node, configure worker nodes, and validate the cluster connection, allowing you to proceed with more advanced Kubernetes operations.

1. Now we can see the docker container in the worker node

    docker ps
   

   

2. Optional: To delete a pod

     kubectl delete pod <pod-name>