From 79ec052d56fdf73366354eee78aecac616a800c2 Mon Sep 17 00:00:00 2001
From: Muthukumar Subramaniam <msmkumar.eee@gmail.com>
Date: Wed, 4 Sep 2024 00:22:11 +0530
Subject: [PATCH] First commit : add install-k8s-on-linux.sh

---
 install-k8s-on-linux.sh | 983 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 983 insertions(+)
 create mode 100644 install-k8s-on-linux.sh

diff --git a/install-k8s-on-linux.sh b/install-k8s-on-linux.sh
new file mode 100644
index 0000000..f49baf1
--- /dev/null
+++ b/install-k8s-on-linux.sh
@@ -0,0 +1,983 @@
+#!/bin/bash
+
+fn_execution_denied_message() {
+cat << EOF
+
+Please run this script as user who has sudo access with NOPASSWD !
+Important Notes: 
+	1) Please don't execute the script with sudo command in front of the script.
+	2) Running the script as root user is not supported as a best practice.
+
+EOF
+}
+
+if ! sudo -u "${USER}" sudo -l | grep -i NOPASSWD &>/dev/null
+then
+	fn_execution_denied_message
+	exit
+fi
+
+if [[ "${USER}" == "root" ]]
+then
+	fn_execution_denied_message
+	exit
+fi
+
+var_k8s_user="${USER}"
+var_k8s_user_home="/home/${var_k8s_user}"
+
+fn_k8s_main_menu() {
+	
+	var_input_provided_1="${1}"
+	var_input_provided_2="${2}"
+	var_input_provided_3="${3}"
+	var_input_provided_4="${4}"
+
+	fn_usage_general() {
+
+cat << EOF
+
+Usage: ${0} [OPTIONS for control plane node or worker node]
+
+	Installs and configures control plane node or worker node with latest stable k8s version available.
+	Supported distributions : Red Hat based, Debian based, SUSE based).
+
+	Also latest versions of below components are installed,
+		Container runtime used : containerd
+		Low-level container runtime : runc ( dependency of containerd )
+		CNI plugin used : calico (default) (or) calico tigera (optional)
+		Storage Driver : csi smb driver
+
+EOF
+	}
+
+	fn_usage_ctrl_plane_node() {
+
+cat << EOF
+Control Plane Node :
+
+	--ctrl-plane-node	installs and configures control plane node with latest k8s version.
+	--pod-network-cidr	this option sets the CIDR of your choice for the pod network.
+	--calico-with-tigera	optional - calico with tigera is installed instead of basic calico CNI setup.
+
+	Example Usage : ${0} --ctrl-plane-node --pod-network-cidr 10.8.0.0/16
+
+	(OR)
+
+	Example Usage : ${0} --ctrl-plane-node --pod-network-cidr 10.8.0.0/16 --calico-with-tigera
+
+	Important notes on option --pod-network-cidr :
+
+		1) Only accepts networks that falls within private address space ( RFC 1918 ).
+		   ( https://datatracker.ietf.org/doc/html/rfc1918 )
+		2) As a best practice, CIDR prefixes /16 to /28 are only allowed.
+		4) Please make sure it doen't overlap with any other networks in your infrastructure.
+		5) Please choose a CIDR block that is large enough for your environment.
+
+EOF
+	}
+
+	fn_usage_worker_node() {
+
+cat << EOF
+Worker Nodes :
+
+	--worker-node	installs and configures worker node with latest k8s version.
+	--install-kubectl	optional - install kubectl tool on the worker node.	
+
+	Example Usage : ${0} --worker-node
+
+	(OR)
+
+	Example Usage : ${0} --worker-node --install-kubectl
+
+	Note :
+		kubectl is not installed on worker nodes as it is unnecessary on worker nodes.
+		( kubelet and kubeadm is enough for worker node functionality and management )
+		kubectl tool is installed on control plane node where we manage the cluster.
+		Also, it can be installed anywhere providing we have access to the cluster API server.
+
+EOF
+	}
+	
+	if [[ "${var_input_provided_1}" == "--ctrl-plane-node" ]]
+	then
+		if [[ -z "${var_input_provided_2}" ]] || [[ "${var_input_provided_2}" != "--pod-network-cidr" ]]
+		then
+			echo -e "\noption --ctrl-plane-node requires --pod-network-cidr with network CIDR! \n"
+			fn_usage_ctrl_plane_node
+			exit
+		fi
+
+		var_k8s_node_type='ctrl-plane'
+
+	elif [[  "${var_input_provided_1}" == "--worker-node" ]]
+	then
+		if [[ ! -z "${var_input_provided_2}" ]] && [[ "${var_input_provided_2}" != "--install-kubectl" ]]
+		then
+			echo -e "\noption --worker-node doesn't take any arguements other than optional --install-kubectl !  \n"
+			fn_usage_worker_node
+			exit
+		fi
+
+		if [[ "${var_input_provided_2}" == "--install-kubectl" ]]
+		then
+			var_install_kubectl_on_worker='yes'
+		fi
+
+		var_k8s_node_type='worker'
+	else
+		fn_usage_general 
+		fn_usage_ctrl_plane_node
+		fn_usage_worker_node 
+		exit
+	fi
+
+	if [[ "${var_input_provided_1}" == "--ctrl-plane-node" ]] && [[ "${var_input_provided_2}" == "--pod-network-cidr" ]]
+	then
+		if [ -z "${var_input_provided_3}" ]
+		then
+			echo -e "\n--pod-network-cidr requires a network CIDR as arguement! \n"
+			fn_usage_ctrl_plane_node
+			exit
+		fi
+		
+		if [[ ! "${var_input_provided_3}" =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.0/[0-9]{1,2}$ ]]
+		then
+    			echo -e "\nInvalid pod network CIDR ${var_input_provided_3} ! \n"
+			fn_usage_ctrl_plane_node
+			exit
+  		fi
+
+		if ! echo "${var_input_provided_3}" |  grep -E '^(192\.168|10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\.)' &>/dev/null
+		then
+			echo -e "\nPod network ${var_input_provided_3} doesn't fall under private address space ( RFC 1918 ) !\n"
+			fn_usage_ctrl_plane_node
+			exit
+		elif  echo "${var_input_provided_3}" | grep '^10\.96\.' &>/dev/null
+		then
+			echo -e "\nPod network ${var_input_provided_3} overlaps with k8s default internal Cluster IP network 10.96.0.0/16 !\n" 
+			fn_usage_ctrl_plane_node
+			exit
+		fi
+
+		if [[ "${var_input_provided_3##*/}" -lt 16 ]] || [[ "${var_input_provided_3##*/}" -gt 28 ]]
+		then
+			echo -e "\nInvalid pod network CIDR prefix /${var_input_provided_3##*/}, as a best practice only /16 to /28 is accepted! \n"
+			fn_usage_ctrl_plane_node
+			exit
+		fi
+
+		var_k8s_pod_network_cidr="${var_input_provided_3}"
+
+		if [[ "${var_input_provided_4}" == "--calico-with-tigera" ]]
+		then
+			var_k8s_calico_tigera_operator='yes'
+		fi
+	fi
+}
+
+
+fn_check_internet_connectivity() {
+	while :
+	do
+		echo -e "\nChecking Internet connectivity as the next step requires it . . ."
+		if ! ping -c 1 google.com &>/dev/null
+		then 
+			echo -e "\nInternet connection is down! "
+			echo -e "Waiting for 10 seconds to check again . . .\n"
+			sleep 10
+			continue
+		else
+			echo -e "\nInternet connection is active.\n"
+			break
+		fi
+	done
+}
+
+
+fn_set_version_variables() {
+
+	fn_get_latest_version() {
+		
+		var_api_url="${1}"
+		var_software_name="${2}"
+		var_git_repo_url="${3}"
+		
+		fn_check_internet_connectivity
+		
+		var_latest_version=$(curl -s -L "${var_api_url}" | jq -r '.tag_name' 2>>/dev/null | tr -d '[:space:]')
+		
+		if [[ ! "${var_latest_version}" =~ v[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+ ]] 
+		then
+			echo -e "\nFailed to fetch latest version of "${var_software_name}" ! \n"
+			
+			while :
+			do
+				echo "Login to the host ${var_k8s_host} via ssh and switch to directory ${var_k8s_cfg_dir}."
+				echo "Refer : ${var_git_repo_url}"
+				echo "Create a file ${var_software_name}_version.txt with the version in the format v*.*.*"
+				echo "Waiting for 5 seconds to refer the file ${var_k8s_cfg_dir}/${var_software_name}_version . . ."
+				sleep 5				
+				
+				if [ -f "${var_k8s_cfg_dir}"/"${var_software_name}"_version ]
+				then
+					var_latest_version=$(cat "${var_k8s_cfg_dir}"/"${var_software_name}"_version | tr -d '[:space:]' | sed '/^$/d')
+				else
+					continue
+				fi
+				
+				if [[ "${var_latest_version}" =~ v[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+ ]]
+				then
+					break
+				else
+					echo -e "Incorrect format of version in "${var_k8s_cfg_dir}"/"${var_software_name}"_version! \n"
+					echo -e "The format should be vMAJOR.MINOR.PATCH ( Semantic Versioning )"
+					echo -e "Current version mentioned : $(cat "${var_k8s_cfg_dir}"/"${var_software_name}"_version) \n"
+					continue
+				fi
+			done
+						
+		fi
+	}
+	
+	echo -e "Fetching latest version information of k8s . . . \n"
+	fn_get_latest_version "https://api.github.com/repos/kubernetes/kubernetes/releases/latest" "k8s" "https://github.com/kubernetes/kubernetes"
+	var_k8s_version="${var_latest_version}"
+	echo -e "Latest version of k8s is ${var_k8s_version} \n"
+	
+	echo -e "Fetching latest version information of containerd . . . \n"
+	fn_get_latest_version "https://api.github.com/repos/containerd/containerd/releases/latest" "containerd" "https://github.com/containerd/containerd"
+	var_containerd_version="${var_latest_version}"
+	echo -e "Latest version of containerd is ${var_containerd_version} \n"
+	
+	echo -e "Fetching latest version information of runc . . . \n"
+	fn_get_latest_version "https://api.github.com/repos/opencontainers/runc/releases/latest" "runc" "https://github.com/opencontainers/runc"
+	var_runc_version="${var_latest_version}"
+	echo -e "Latest version of runc is ${var_runc_version} \n"
+	
+	if [[ "${var_k8s_node_type}" == "ctrl-plane" ]]
+	then
+		echo -e "Fetching latest version information of calico . . . \n"
+		fn_get_latest_version "https://api.github.com/repos/projectcalico/calico/releases/latest" "calico" "https://github.com/projectcalico/calico"
+		var_calico_version="${var_latest_version}"
+		echo -e "Latest version of calico is ${var_calico_version} \n"
+		
+		echo -e "Fetching latest version information csi-driver-smb . . . \n"
+		fn_get_latest_version "https://api.github.com/repos/kubernetes-csi/csi-driver-smb/releases/latest" "csi_smb" "https://github.com/kubernetes-csi/csi-driver-smb"
+		var_csi_smb_version="${var_latest_version}"
+		echo -e "Latest version of csi-driver-smb is ${var_csi_smb_version} \n"
+	fi
+}
+
+
+fn_stage1_configuration() {
+	
+	if [ ! -f "${var_k8s_cfg_dir}"/completed-stage1 ]
+	then
+		clear
+		
+		echo -e "\nStarting stage-1 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} . . .\n"
+		
+		echo -e "\nLoading required kernel modules . . .\n"
+		
+		sudo modprobe -vv overlay
+		sudo modprobe -vv br_netfilter
+
+cat << EOF | sudo tee /etc/modules-load.d/k8s.conf
+overlay
+br_netfilter
+EOF
+		
+		echo -e "\nLoading required kernel parameters . . .\n"
+		
+cat << EOF | sudo tee /etc/sysctl.d/k8s.conf
+net.ipv4.ip_forward = 1
+net.bridge.bridge-nf-call-ip6tables = 1
+net.bridge.bridge-nf-call-iptables = 1
+EOF
+		
+		sudo sysctl --system
+		
+		fn_check_internet_connectivity
+		
+		echo -e "\nDownloading container runtime containerd . . ."
+		echo "(This might take some time depending on the internet speed)"
+		
+		
+		wget -P "${var_k8s_cfg_dir}"/ https://github.com/containerd/containerd/releases/download/"${var_containerd_version}"/containerd-"${var_containerd_version:1}"-linux-amd64.tar.gz -a "${var_logs_file}" 
+		
+		echo -e "\nConfiguring containerd . . .\n"
+
+		mkdir "${var_k8s_cfg_dir}"/containerd
+		
+		tar Cxzvf "${var_k8s_cfg_dir}"/containerd/ "${var_k8s_cfg_dir}"/containerd-"${var_containerd_version:1}"-linux-amd64.tar.gz
+		
+		chmod -R +x "${var_k8s_cfg_dir}"/containerd/bin
+
+		sudo chown -R root:root "${var_k8s_cfg_dir}"/containerd/bin
+		
+		sudo rsync -avPh "${var_k8s_cfg_dir}"/containerd/bin/ /usr/local/bin/ && sudo rm -rf "${var_k8s_cfg_dir}"/containerd*
+		
+		sudo mkdir -p /etc/containerd
+		
+		echo -e "\nChecking containerd version . . ."
+		
+		containerd --version
+		
+		containerd config default | sudo tee /etc/containerd/config.toml
+
+		sudo sed -i "/SystemdCgroup/s/false/true/g" /etc/containerd/config.toml
+		
+		containerd config dump | grep SystemdCgroup
+		
+		fn_check_internet_connectivity
+		
+		echo -e "Downloading containerd.service file from github . . .\n"
+		
+		sudo wget -P /etc/systemd/system/ https://raw.githubusercontent.com/containerd/containerd/main/containerd.service -a "${var_logs_file}"
+
+		echo -e "\nStarting the containerd.service . . .\n"
+		
+		sudo systemctl daemon-reload
+		
+		sudo systemctl enable --now containerd.service
+		
+		sudo systemctl status containerd.service --no-pager
+		
+		fn_check_internet_connectivity
+		
+		echo -e "\nDownloading low-level container runtime runc ( dependency of containerd ) . . ."
+		echo "(This might take some time depending on the internet speed)"
+		
+		sudo wget -P /usr/local/bin/ https://github.com/opencontainers/runc/releases/download/"${var_runc_version}"/runc.amd64 -a "${var_logs_file}" 
+		
+		echo -e "\nConfiguring runc . . .\n"
+		sudo mv /usr/local/bin/runc.amd64 /usr/local/bin/runc
+		sudo chmod +x /usr/local/bin/runc
+		
+		runc --version
+		
+		echo -e "\nCompleted stage-1 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} ! \n"
+		
+		touch "${var_k8s_cfg_dir}"/completed-stage1
+		
+		sleep 2
+		
+	fi
+}
+
+
+fn_stage2_for_redhat_based() {
+	
+	if [ ! -f "${var_k8s_cfg_dir}"/completed-stage2 ]
+	then
+		
+		clear
+		
+		echo -e "\nStarting stage-2 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} . . .\n"
+		
+		fn_check_internet_connectivity
+		
+		echo -e "\nConfiguring k8s rpm repository and installing required packages . . .\n"
+		
+		var_k8s_version_major=$(echo "${var_k8s_version}" | cut -d "." -f 1)
+		var_k8s_version_minor=$(echo "${var_k8s_version}" | cut -d "." -f 2)
+		var_k8s_version_major_minor="${var_k8s_version_major}.${var_k8s_version_minor}"
+		
+cat << EOF | sudo tee /etc/yum.repos.d/k8s.repo
+[k8s-${var_k8s_version_major_minor}]
+name=k8s-${var_k8s_version_major_minor}
+baseurl=https://pkgs.k8s.io/core:/stable:/${var_k8s_version_major_minor}/rpm/
+enabled=1
+gpgcheck=1
+gpgkey=https://pkgs.k8s.io/core:/stable:/${var_k8s_version_major_minor}/rpm/repodata/repomd.xml.key
+exclude=kubelet kubeadm kubectl
+EOF
+		
+		sudo dnf makecache
+
+		if [[ "${var_k8s_node_type}" == "ctrl-plane" ]] || [[ "${var_install_kubectl_on_worker}" == "yes" ]]
+		then
+			sudo dnf install -y kubelet kubeadm kubectl --disableexcludes=k8s-"${var_k8s_version_major_minor}"
+		else
+			sudo dnf install -y kubelet kubeadm --disableexcludes=k8s-"${var_k8s_version_major_minor}"
+		fi
+		
+		echo -e "\nCompleted stage-2 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} ! \n"
+		
+		touch "${var_k8s_cfg_dir}"/completed-stage2
+	fi
+}
+
+
+fn_stage2_for_debian_based() {
+			
+	if [ ! -f "${var_k8s_cfg_dir}"/completed-stage2 ]
+	then
+		clear
+		
+		echo -e "\nStarting stage-2 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} . . .\n"
+			
+		fn_check_internet_connectivity
+			
+		echo -e "\nConfiguring k8s deb repository and installing required packages . . .\n"
+			
+		var_k8s_version_major=$(echo "${var_k8s_version}" | cut -d "." -f 1)
+		var_k8s_version_minor=$(echo "${var_k8s_version}" | cut -d "." -f 2)
+		var_k8s_version_major_minor="${var_k8s_version_major}.${var_k8s_version_minor}"
+			
+		echo "deb [signed-by=/etc/apt/keyrings/k8s-apt-keyring-${var_k8s_version_major_minor}.gpg] https://pkgs.k8s.io/core:/stable:/${var_k8s_version_major_minor}/deb/ /" | sudo tee /etc/apt/sources.list.d/k8s.list
+			
+		curl -fsSL https://pkgs.k8s.io/core:/stable:/"${var_k8s_version_major_minor}"/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/k8s-apt-keyring-"${var_k8s_version_major_minor}".gpg
+			
+		sudo apt-get update
+		
+		if [[ "${var_k8s_node_type}" == "ctrl-plane" ]] || [[ "${var_install_kubectl_on_worker}" == "yes" ]]
+		then
+			sudo apt-get install -y kubelet kubeadm kubectl
+		
+			sudo apt-mark hold kubelet kubeadm kubectl
+		else
+			sudo apt-get install -y kubelet kubeadm
+
+			sudo apt-mark hold kubelet kubeadm
+		fi
+		
+		echo -e "\nCompleted stage-2 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} ! \n"
+		
+		touch "${var_k8s_cfg_dir}"/completed-stage2
+	fi
+}
+
+
+fn_stage2_for_suse_based() {
+	
+	if [ ! -f "${var_k8s_cfg_dir}"/completed-stage2 ]
+	then
+		clear
+		
+		echo -e "\nStarting stage-2 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} . . .\n"
+		
+		fn_check_internet_connectivity
+		
+		echo -e "\nConfiguring k8s rpm repository and installing required packages . . .\n"
+		
+		var_k8s_version_major=$(echo "${var_k8s_version}" | cut -d "." -f 1)
+		var_k8s_version_minor=$(echo "${var_k8s_version}" | cut -d "." -f 2)
+		var_k8s_version_major_minor="${var_k8s_version_major}.${var_k8s_version_minor}"
+		
+cat <<EOF | sudo tee /etc/zypp/repos.d/k8s.repo
+[k8s-${var_k8s_version_major_minor}]
+name=k8s-${var_k8s_version_major_minor}
+baseurl=https://pkgs.k8s.io/core:/stable:/${var_k8s_version_major_minor}/rpm/
+enabled=1
+gpgcheck=1
+gpgkey=https://pkgs.k8s.io/core:/stable:/${var_k8s_version_major_minor}/rpm/repodata/repomd.xml.key
+[conntrack-for-suse]
+name=conntrack-for-suse
+baseurl=https://ks-manager-provided-web-server-name/k8s-install/suse/rpm/
+enabled=1
+gpgcheck=0
+EOF
+		
+		fn_check_internet_connectivity
+		
+		sudo zypper --gpg-auto-import-keys refresh
+		
+		fn_check_internet_connectivity
+
+		if [[ "${var_k8s_node_type}" == "ctrl-plane" ]] || [[ "${var_install_kubectl_on_worker}" == "yes" ]]
+		then
+			sudo zypper install -y kubelet kubeadm kubectl
+		
+			sudo zypper addlock kubelet kubeadm kubectl
+		else
+
+			sudo zypper install -y kubelet kubeadm
+		
+			sudo zypper addlock kubelet kubeadm
+		fi
+		
+		sudo zypper ll
+
+		touch "${var_k8s_cfg_dir}"/completed-stage2
+		
+		echo -e "\nCompleted stage-2 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} ! \n"
+	fi
+}
+
+
+fn_stage3_configuration() {
+	
+	if [ ! -f "${var_k8s_cfg_dir}"/completed-stage3 ]
+	then
+		echo -e "\nStarting stage-3 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} . . .\n"
+
+		echo -e "Starting kubelet.service . . .\n"
+		
+		sudo systemctl enable --now kubelet.service
+		
+		sudo systemctl status kubelet.service --no-pager
+		
+		#Below are k8s  ${var_k8s_node_type} node specific configurations
+		
+		fn_check_internet_connectivity
+		
+		echo -e "\nPulling required images of k8s core pods . . ."
+		echo -e "(This might take considerable amount of time depending on the internet speed)\n"
+		
+		sudo nice -n -20 kubeadm config images pull
+		
+		echo -e "\nStarting the cluster creation . . .\n"
+		
+		sudo kubeadm init --pod-network-cidr="${var_k8s_pod_network_cidr}"
+		
+		echo -e "\nStarting the cluster configuration . . .\n"
+
+		echo -e "Updating kubectl configs under ${var_k8s_user_home} for user ${var_k8s_user} . . ."
+		
+		#echo 'export KUBECONFIG=/etc/kubernetes/admin.conf' >> /root/.bashrc     ## For root user only
+		#echo 'source <(kubectl completion bash)' >> /root/.bashrc               ## For root user only
+
+		echo 'source <(kubectl completion bash)' >> "${var_k8s_user_home}"/.bashrc
+		# shellcheck disable=SC1091
+		source "${var_k8s_user_home}"/.bashrc
+		
+		mkdir -p "${var_k8s_user_home}"/.kube
+		sudo cp -i /etc/kubernetes/admin.conf "${var_k8s_user_home}"/.kube/config
+		sudo chown $(id -u "${var_k8s_user}"):$(id -g "${var_k8s_user}") "${var_k8s_user_home}"/.kube/config
+		
+		while :
+		do
+			echo -e "\nWaiting for API Server pod to come online . . .\n"
+        		if ! kubectl get pods -n kube-system | grep -P '^kube-apiserver.*1/1.*Running*' &>/dev/null
+        		then
+				kubectl get pods -n kube-system | grep 'kube-apiserver'
+                		sleep 2
+                		continue
+        		else
+				sleep 2
+                		kubectl get pods -n kube-system | grep 'kube-apiserver'
+                		break
+        		fi
+		done
+
+
+		if [[ "${var_k8s_calico_tigera_operator}" == "yes" ]]
+		then
+			#In Case of tigera operator based calcio CNI setup
+
+			echo -e "\nDownloading the Calico Tigera Operator manifest for Calico CNI ( Container Network Interface ) . . .\n"
+		
+			fn_check_internet_connectivity
+
+			wget -P "${var_k8s_cfg_dir}"/ https://raw.githubusercontent.com/projectcalico/calico/${var_calico_version}/manifests/tigera-operator.yaml -a "${var_logs_file}"
+
+			echo -e "\nDeploying Calico Tigera Operator based calico CNI . . .\n"
+
+			kubectl create -f "${var_k8s_cfg_dir}"/tigera-operator.yaml
+			
+			echo -e "\nDownloading the custom-resources manifest for Calico Tigera Operator . . .\n"
+			
+			fn_check_internet_connectivity
+
+			wget -P ${var_k8s_cfg_dir}/  https://raw.githubusercontent.com/projectcalico/calico/${var_calico_version}/manifests/custom-resources.yaml -a "${var_logs_file}"
+
+			echo -e "\nCreating custom-resources of calico Tigera Operator with pod network ${var_k8s_pod_network_cidr} . . .\n"
+
+			sed -i "s:192.168.0.0/16:${var_k8s_pod_network_cidr}:g" ${var_k8s_cfg_dir}/custom-resources.yaml
+
+			kubectl create -f "${var_k8s_cfg_dir}"/custom-resources.yaml
+
+		else
+			#In case of Basic Calico CNI ( Container Network Interface )
+
+			echo -e "\nDownloading the calico manifest for Calico CNI ( Container Network Interface ) . . .\n"
+
+			fn_check_internet_connectivity
+
+			wget -P "${var_k8s_cfg_dir}"/ https://raw.githubusercontent.com/projectcalico/calico/"${var_calico_version}"/manifests/calico.yaml -a "${var_logs_file}"
+		
+			echo -e "\nConfiguring calico with pod network as ${var_k8s_pod_network_cidr} . . .\n"
+			
+			kubectl apply -f "${var_k8s_cfg_dir}"/calico.yaml
+		fi
+		
+		kubectl get nodes
+		
+		echo -e "\nCommand to join worker nodes is located in ${var_k8s_cfg_dir}/worker-node-join-command !! \n"
+		
+		sleep 2
+		
+		clear
+		
+		echo -e "\nProceeding with post-installation configurations . . .\n"
+		
+		# Waiting for control plane to become ready
+		while :
+		do
+			echo -e "\nWaiting for ${var_k8s_node_type} to get Ready . . .\n"
+			if kubectl get nodes | grep -w " Ready " &>/dev/null
+			then
+				kubectl get nodes
+				kubectl get pods -A
+				break
+			else
+				kubectl get nodes
+				kubectl get pods -A
+				sleep 2
+				continue
+			fi
+		done
+		
+		fn_check_internet_connectivity
+		
+		echo -e "\nInstalling CSI SMB drivers by remote internet connection . . .\n" 
+		
+		curl -skSL https://raw.githubusercontent.com/kubernetes-csi/csi-driver-smb/"${var_csi_smb_version}"/deploy/install-driver.sh | bash -s "${var_csi_smb_version}" --
+			
+		# Wait until all pods are running
+			
+		while :
+		do
+			echo -e "\nWaiting for CSI SMB pods creation to start . . .\n"
+			if kubectl get pods -A | grep csi-smb;then break;fi
+			sleep 2
+		done
+			
+		while :
+		do
+			echo -e "\nWaiting for all the required ${var_k8s_node_type} pods to come online . . .\n"
+			if kubectl get pods --all-namespaces -o jsonpath='{.items[*].status.containerStatuses[*].ready}' | grep false &>/dev/nul
+			then 
+				kubectl get pods --all-namespaces
+				sleep 5
+				continue
+			else 
+				kubectl get pods --all-namespaces
+				break
+			fi
+		done
+
+		var_k8s_kube_system_pods_total=$(kubectl get pods -A | tail -n +2  | wc -l)
+
+		while :
+		do
+			echo -e "\nWaiting for all the required ${var_k8s_node_type} pods to come online . . .\n"
+
+			var_k8s_kube_system_pods_running=$(kubectl get pods -A | tail -n +2  | grep " Running " | wc -l)
+
+			if [[ "${var_k8s_kube_system_pods_total}" -ne "${var_k8s_kube_system_pods_running}" ]]
+			then
+				kubectl get pods -A
+				sleep 5
+				continue
+			else
+				echo -e "\nAll the required pods for ${var_k8s_node_type} are now Running! \n"
+				kubectl get pods -A
+				break
+			fi
+		done
+
+		kubectl get nodes
+
+		echo -e "\nCompleted stage-3 of k8s ${var_k8s_node_type} node configuration on ${var_k8s_host} ! \n"
+		
+		touch "${var_k8s_cfg_dir}"/completed-stage3
+	fi
+}
+
+#### End of Function Definitions ####
+
+
+fn_k8s_main_menu "${1}" "${2}" "${3}" "${4}"
+
+var_k8s_host=$(hostname -f)
+var_k8s_cfg_dir="${var_k8s_user_home}/install-k8s-on-linux"
+var_logs_file="${var_k8s_cfg_dir}/logs-install-k8s-on-linux-${var_k8s_node_type}.log"
+
+mkdir -p "${var_k8s_cfg_dir}"
+touch "${var_logs_file}"
+
+if [ ! -f "${var_k8s_user_home}"/install-k8s-on-linux/$(basename "${0}") ]
+then
+	cp -p "${0}" "${var_k8s_cfg_dir}"/
+fi
+
+{
+	if [ ! -f /etc/systemd/system/install-k8s-on-linux-"${var_k8s_node_type}".service ]
+	then
+		clear
+
+		echo -e "\nCreating systemd service install-k8s-on-linux-"${var_k8s_node_type}".service . . .\n"
+
+		if [[ "${var_k8s_node_type}" == "ctrl-plane" ]]
+		then
+
+			if [[ "${var_k8s_calico_tigera_operator}" != "yes" ]]
+			then
+cat << EOF | sudo tee /etc/systemd/system/install-k8s-on-linux-"${var_k8s_node_type}".service
+[Unit]
+Description=Service to install and configure k8s ctrl-plane node
+After=multi-user.target
+
+[Service]
+User=${var_k8s_user}
+Environment="HOME=${var_k8s_user_home}"
+ExecStart=/usr/bin/bash ${var_k8s_user_home}/install-k8s-on-linux/$(basename ${0}) --ctrl-plane-node --pod-network-cidr ${var_k8s_pod_network_cidr} 
+
+[Install]
+WantedBy=multi-user.target
+EOF
+			else
+cat << EOF | sudo tee /etc/systemd/system/install-k8s-on-linux-"${var_k8s_node_type}".service
+[Unit]
+Description=Service to install and configure k8s ctrl-plane node
+After=multi-user.target
+
+[Service]
+User=${var_k8s_user}
+Environment="HOME=${var_k8s_user_home}"
+ExecStart=/usr/bin/bash ${var_k8s_user_home}/install-k8s-on-linux/$(basename ${0}) --ctrl-plane-node --pod-network-cidr ${var_k8s_pod_network_cidr} --calico-with-tigera 
+
+[Install]
+WantedBy=multi-user.target
+EOF
+			fi
+
+
+		elif [[ "${var_k8s_node_type}" == "worker" ]]
+		then
+			if [[ "${var_install_kubectl_on_worker}" != "yes" ]]
+			then
+
+cat << EOF | sudo tee /etc/systemd/system/install-k8s-on-linux-"${var_k8s_node_type}".service
+[Unit]
+Description=Service to install and configure k8s worker node
+After=multi-user.target
+
+[Service]
+User=${var_k8s_user}
+Environment="HOME=${var_k8s_user_home}"
+ExecStart=/usr/bin/bash ${var_k8s_user_home}/install-k8s-on-linux/$(basename ${0}) --worker-node
+
+[Install]
+WantedBy=multi-user.target
+EOF
+			else
+
+cat << EOF | sudo tee /etc/systemd/system/install-k8s-on-linux-"${var_k8s_node_type}".service
+[Unit]
+Description=Service to install and configure k8s worker node
+After=multi-user.target
+
+[Service]
+User=${var_k8s_user}
+Environment="HOME=${var_k8s_user_home}"
+ExecStart=/usr/bin/bash ${var_k8s_user_home}/install-k8s-on-linux/$(basename ${0}) --worker-node --install-kubectl
+
+[Install]
+WantedBy=multi-user.target
+EOF
+			fi
+		fi
+
+		sudo systemctl daemon-reload
+
+		sudo systemctl enable install-k8s-on-linux-"${var_k8s_node_type}".service
+
+		echo -e "\nStarting the service install-k8s-on-linux-${var_k8s_node_type}.service . . .\n"
+
+		sudo systemctl start install-k8s-on-linux-"${var_k8s_node_type}".service
+
+		sudo systemctl status install-k8s-on-linux-"${var_k8s_node_type}".service  --no-pager
+
+		echo -e "\ninstall-k8s-on-linux-${var_k8s_node_type}.service will be disabled automatically once the k8s ${var_k8s_node_type} installtion and configurations are completed."
+
+		echo -e "\nWe are good to go my dear! Just sit back and relax!\n"
+
+		echo -e "\nYou can track the installation logs from system console! \n"
+
+	       	echo -e "Also by : tail -f ${var_logs_file} \n"
+
+		echo -e "\nTo check systemd service execution logs : journalctl -u install-k8s-on-linux-${var_k8s_node_type}.service\n"
+
+		exit
+	fi
+
+
+	if [ ! -f "${var_k8s_cfg_dir}"/successful ]
+	then
+		
+		echo -e "\nStarted service install-k8s-on-linux-${var_k8s_node_type} . . .\n"
+
+		echo -e "\nTurning off swap if enabled . . .\n"
+
+		sudo swapoff -a
+
+		sudo sed -i '/swap/s/^/#/' /etc/fstab
+
+		if grep -i -E "rhel|fedora" /etc/os-release &>/dev/null
+		then
+			echo -e "\nUpgrading all installed packages in the system if required . . .\n"
+			fn_check_internet_connectivity
+			sudo dnf clean all
+			sudo dnf update --refresh -y
+			echo -e "\nInstalling some required basic packages . . .\n"
+			fn_check_internet_connectivity
+			sudo dnf install -y curl wget rsync jq
+			fn_set_version_variables
+			fn_stage1_configuration
+			fn_stage2_for_redhat_based
+		fi
+
+		if grep -i -E "ubuntu|debian" /etc/os-release &>/dev/null
+		then
+			echo -e "\nUpgrading all installed packages in the system if required . . .\n"
+			fn_check_internet_connectivity
+			sudo apt-get clean 
+			sudo apt-get update
+			fn_check_internet_connectivity
+			sudo apt-get upgrade -y
+			echo -e "\nInstalling some required basic packages . . .\n"
+			fn_check_internet_connectivity
+			sudo apt-get install -y curl wget rsync gpg jq
+			fn_set_version_variables
+			fn_stage1_configuration
+			fn_stage2_for_debian_based
+		fi
+
+		if grep -i "suse" /etc/os-release &>/dev/null
+		then
+			echo -e "\nUpgrading all installed packages in the system if required . . .\n"
+			fn_check_internet_connectivity
+			sudo zypper clean -a 
+			sudo zypper refresh
+			fn_check_internet_connectivity
+			sudo zypper update -y 
+			echo -e "\nInstalling some basic required packages . . .\n"
+			fn_check_internet_connectivity
+			sudo zypper install -y curl wget rsync jq
+			fn_set_version_variables
+			fn_stage1_configuration
+			fn_stage2_for_suse_based 
+		fi
+
+		if [[ "${var_k8s_node_type}" == "ctrl-plane" ]]
+		then
+			fn_stage3_configuration
+
+			echo -e "\nGoing for a reboot in 5 seconds to make sure all necessary changes takes effect! \n" 
+			
+			touch "${var_k8s_cfg_dir}"/successful
+
+			sleep 5
+
+			sudo reboot
+
+		else
+			echo -e "Starting kubelet.service . . .\n"
+
+			sudo systemctl enable --now kubelet.service
+
+			sudo systemctl status kubelet.service --no-pager
+
+			echo -e "\nGoing for a reboot in 5 seconds to make sure all necessary changes takes effect! \n" 
+			
+			touch "${var_k8s_cfg_dir}"/successful
+
+			sleep 5
+
+			sudo reboot
+		fi
+	else
+
+		sleep 3
+		
+		if [[ "${var_k8s_node_type}" == "ctrl-plane" ]]
+		then
+			echo -e "\nWaiting for API Server pod to come online . . .\n"
+
+			while true :
+			do
+
+				if ! kubectl get pods -n kube-system | grep -P '^kube-apiserver.*1/1.*Running*' &>/dev/null
+        			then
+                			sleep 2
+                			continue
+        			else
+					sleep 2
+					kubectl get pods -n kube-system | grep 'kube-apiserver'
+                			break
+        			fi
+			done
+
+			echo -e "\nWaiting for all the control-plane pods to come online . . .\n"
+
+			var_k8s_kube_system_pods_total=$(kubectl get pods -A | tail -n +2  | wc -l)
+
+			while :
+			do
+				var_k8s_kube_system_pods_running=$(kubectl get pods -A | tail -n +2  | grep " Running " | wc -l)
+				if [[ "${var_k8s_kube_system_pods_total}" -ne "${var_k8s_kube_system_pods_running}" ]]
+				then
+					sleep 2
+					continue
+				else
+					kubectl get pods -A
+					break
+				fi
+			done
+			
+			echo -e "\nkubelet version: $(kubelet --version)\n"
+
+			echo -e "$(kubeadm version)\n"
+
+			echo -e "kubectl version:\n$(kubectl version)\n"
+
+			while :
+			do
+				if kubectl get nodes | grep -w " Ready " &>/dev/null
+				then
+					kubectl get nodes
+					break
+				else
+					sleep 2
+					continue
+				fi
+			done
+
+		else
+		
+			echo -e "\nFrom ctrl-plane node,\nRun \"kubeadm token create --print-join-command\" to create join command.\n"
+			
+			echo -e "\nJoin the ${var_k8s_node_type} node ${var_k8s_host} with k8s cluster using above provided kubeadm join command.\n"
+			sudo systemctl status kubelet.service --no-pager
+
+			echo -e "\nIgnore if kubelet.service service is not running! \n"
+
+			echo -e "\nThe kubelet.service will start automatically when this ${var_k8s_node_type} node is joined with ctrl-plane node! \n"
+			echo -e "\nkubelet version: $(kubelet --version)\n"
+
+			echo -e "$(kubeadm version)\n"
+
+			if [[ "${var_install_kubectl_on_worker}" == "yes" ]]
+			then
+				echo -e "\nkubectl version:\n$(kubectl version --client)\n"
+			fi
+
+		fi
+
+		echo -e "\nSuccessfully completed installation and configuration of k8s ${var_k8s_node_type} node on ${var_k8s_host} ! \n"
+			
+		if [ -f /etc/systemd/system/install-k8s-on-linux-"${var_k8s_node_type}".service ]
+		then
+			sudo systemctl disable install-k8s-on-linux-"${var_k8s_node_type}".service
+		fi
+
+	fi
+
+} | sudo tee /dev/tty0 -a "${var_logs_file}"
+
+exit