How To Setup Kubernetes Cluster Using Kubeadm

In this blog post, I have covered the step-by-step guide to setting up a kubernetes cluster using Kubeadm with one master and two worker nodes.

Kubeadm is an excellent tool to set up a working kubernetes cluster in less time. It does all the heavy lifting in terms of setting up all kubernetes cluster components. Also, It follows all the configuration best practices for a kubernetes cluster.

What is Kubeadm?

Kubeadm is a tool to set up a minimum viable Kubernetes cluster without much complex configuration. Also, Kubeadm makes the whole process easy by running a series of prechecks to ensure that the server has all the essential components and configs to run Kubernetes.

It is developed and maintained by the official Kubernetes community. There are other options like minikube, kind, etc., that are pretty easy to set up. You can check out my minikube tutorial. Those are good options with minimum hardware requirements if you are deploying and testing applications on Kubernetes.

But if you want to play around with the cluster components or test utilities that are part of cluster administration, Kubeadm is the best option. Also, you can create a production-like cluster locally on a workstation for development and testing purposes.

Kubeadm Setup Prerequisites

Following are the prerequisites for Kubeadm Kubernetes cluster setup.

[if !supportLists]1. [endif]Minimum two Ubuntu nodes [One master and one worker node]. You can have more worker nodes as per your requirement.

[if !supportLists]2. [endif]The master node should have a minimum of 2 vCPU and 2GB RAM.

[if !supportLists]3. [endif]For the worker nodes, a minimum of 1vCPU and 2 GB RAM is recommended.

[if !supportLists]4. [endif]Network connectivity between the machines

Step 1: Update the system and install necessary packages

On both master and worker nodes

sudo apt update

sudo apt install -y docker.io

sudo systemctl enable docker

sudo systemctl start docker

# Disable swap on both nodes

sudo swapoff -a

sudo sed -i '/ swap / s/^\(.\*\)$/#\1/g' /etc/fstab

Step 2: Install Kubernetes tools on both nodes

# On both master and worker nodes

sudo apt-get update && sudo apt-get install -y apt-transport-https curl

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list

sudo apt update

sudo apt-get install -y kubelet kubeadm kubectl

sudo systemctl enable kubelet

sudo systemctl start kubelet

Step 3: Initialize the Kubernetes master (on the master node)

# On the master node

sudo kubeadm init --pod-network-cidr=10.244.0.0/16

Note the kubeadm join command that is displayed at the end. You'll need this command to join the worker node to the cluster.

Step 4: Set up the kubeconfig for the user (on the master node)

# On the master node

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

Step 5: Install a network plugin (on the master node)

# On the master node

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Step 6: Join the worker node to the cluster (on the worker node)

Use the kubeadm join command that was displayed after initializing the master.

# On the worker node

sudo kubeadm join <master-node-ip>:<master-node-port> --token <token> --discovery-token-ca-cert-hash <hash>

run on Master Node

kubeadm token create --print-join-command

Replace <master-node-ip>, <master-node-port>, <token>, and <hash> with the values specific to your cluster.

Step 7: Verify the cluster (on the master node)

# On the master node

kubectl get nodes

This should display both the master and worker nodes, and their STATUS should be Ready.

Your Kubernetes cluster with one master and one worker node is now set up. You can deploy and manage applications using kubectl.