# Multi-Node Kubernetes Cluster Setup Using Kubeadm

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1700687356342/b2375230-c8ac-4bfb-b5fc-74ebdd2b54e2.jpeg align="center")

This blog provides step-by-step instructions for setting up a multi-node Kubernetes cluster using Kubeadm. Importantly, avoid preflight errors.

# Overview

This guide provides detailed instructions for setting up a multi-node Kubernetes cluster using Kubeadm. The guide includes instructions for installing and configuring containerd and Kubernetes, disabling swap, initializing the cluster, installing Flannel, and joining nodes to the cluster.

## Prerequisites

Before starting the installation process, ensure that the following prerequisites are met:

* You have at least two Ubuntu 18.04 or higher servers available for creating the cluster.
    
* Each server has at least 2GB of RAM and 2 CPU cores.
    
* The servers have network connectivity with each other.
    
* You have root access to each server.
    

## Installation Steps

The following are the step-by-step instructions for setting up a multi-node Kubernetes cluster using Kubeadm:

**Note:** All commands must be run in **root-user** mode. To go to the root, run the following command:

```bash
sudo su
```

Update the system's package list and install the necessary dependencies using the following commands:

```bash
sudo apt-get update
sudo apt install apt-transport-https curl -y
```

## Install containerd

To install Containerd, use the following commands:

```bash
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update
sudo apt-get install containerd.io -y
```

## Create container configuration

Next, create the container configuration file using the following commands:

```bash
sudo mkdir -p /etc/containerd
sudo containerd config default | sudo tee /etc/containerd/config.toml
```

## Edit /etc/containerd/config.toml

Edit the containerd configuration file to set SystemdCgroup to true. Use the following command to open the file:

```bash
sudo nano /etc/containerd/config.toml
```

Set SystemdCgroup to true:

```bash
SystemdCgroup = true
```

Restart containerd:

```bash
sudo systemctl restart containerd
```

## Install Kubernetes

To install Kubernetes, use the following commands:

```bash
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add
sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"
sudo apt install kubeadm kubelet kubectl kubernetes-cni
```

## Disable swap

Disable swap using the following command:

```bash
sudo swapoff -a
```

If there are any swap entries in the /etc/fstab file, remove them using a text editor such as nano:

```bash
sudo nano /etc/fstab
```

Enable kernel modules

```bash
sudo modprobe br_netfilter
```

Add some settings to sysctl

```bash
sudo sysctl -w net.ipv4.ip_forward=1
```

## Initialize the Cluster (Run only on master)

Use the following command to initialize the cluster:

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

Create a .kube directory in your home directory:

```bash
mkdir -p $HOME/.kube
```

Copy the Kubernetes configuration file to your home directory:

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

Change ownership of the file:

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

## Install Flannel (Run only on master)

Use the following command to install Flannel:

```bash
kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/v0.20.2/Documentation/kube-flannel.yml
```

## Verify Installation

Verify that all the pods are up and running.Join Nodes

```bash
kubectl get pods --all-namespaces
```

## Join Nodes

To add nodes to the cluster, run the kubeadm join command with the appropriate arguments on each node. The command will output a token that can be used to join the node to the cluster.

## **The End**