To set up Kubernetes manually on N nodes, you will need to designate one node as the control-plane (master) node and the other as a worker node. In this guide, we'll use Ubuntu as the operating system. Ensure that both nodes meet the following minimum requirements:

• 6443 (API server)
• 2379-2380 (etcd)
• 10250 (kubelet API)
• 10251 (kube-scheduler)
• 10252 (kube-controller-manager)

• 10250 (kubelet API)
• 30000-32767 (NodePort services)

• 2 or more CPU cores
• 2 GB or more of RAM
• A unique hostname, MAC address, and product_uuid for every node
• Full network connectivity between all machines in the cluster
• Swap disabled (Recommended)

sudo su

echo -e '#!/bin/bash\nsudo apt-get update && sudo apt-get upgrade -y\nsudo apt-get install -y docker.io\nsudo systemctl enable docker\nsudo systemctl start docker\nsudo apt-get update && sudo apt-get install -y apt-transport-https curl\ncurl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -\necho "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee -a /etc/apt/sources.list.d/kubernetes.list\nsudo apt-get update -y\nsudo apt-get install -y kubelet kubeadm kubectl\nsudo apt-mark hold kubelet kubeadm kubectl' > install_kubeadm.sh && chmod +x install_kubeadm.sh && ./install_kubeadm.sh

1. On the control-plane node, initialize the Kubernetes cluster using kubeadm:

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

2. After the initialization is complete, copy the kubeadm join command with the associated token and save it for later use.
3. Set up the Kubernetes configuration for the control-plane node:

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

1. On the control-plane node, install a pod network. In this example, we'll use Flannel:

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

1. On the worker node, execute the kubeadm join command you saved earlier. It should look like this:

sudo kubeadm join <control-plane-ip>:6443 --token <token> --discovery-token-ca-cert-hash sha256:<hash>

kubectl get nodes

Note The connection to the server 172.31.2.185:6443 was refused - did you specify the right host or port? Make sure your ports is open if your ports already open then use this steps

sudo cp /etc/kubernetes/admin.conf $HOME/
sudo chown $(id -u):$(id -g) $HOME/admin.conf
export KUBECONFIG=$HOME/admin.conf