install_kubernetes.sh

#!/bin/bash
# common.sh
# copy this script and run in all master and worker nodes
# It has been tested on a AWS EC2 Ubuntu 22.04 LTS2
#i1) Switch to root user [ sudo -i]

#2) Disable swap & add kernel settings

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

#3) Add  kernel settings & Enable IP tables(CNI Prerequisites)

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

sysctl --system

#4) Install containerd run time

#To install containerd, first install its dependencies.

apt-get update -y
apt-get install ca-certificates curl gnupg lsb-release -y

#Note: We are not installing Docker Here.Since containerd.io package is part of docker apt repositories hence we added docker repository & it's key to download and install containerd.
# Add Docker’s official GPG key:
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg

#Use follwing command to set up the repository:

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

# Install containerd

apt-get update -y
apt-get install containerd.io -y

# Generate default configuration file for containerd

#Note: Containerd uses a configuration file located in /etc/containerd/config.toml for specifying daemon level options.
#The default configuration can be generated via below command.

containerd config default > /etc/containerd/config.toml

# Run following command to update configure cgroup as systemd for contianerd.

sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

# Restart and enable containerd service

systemctl restart containerd
systemctl enable containerd

#5) Installing kubeadm, kubelet and kubectl

# Update the apt package index and install packages needed to use the Kubernetes apt repository:

apt-get update
apt-get install -y apt-transport-https ca-certificates curl

# Download the Google Cloud public signing key:
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

# Add the Kubernetes apt repository:
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update apt package index, install kubelet, kubeadm and kubectl, and pin their version:
apt-get update
apt install -y kubeadm=1.28.1-1.1 kubelet=1.28.1-1.1 kubectl=1.28.1-1.1

# apt-mark hold will prevent the package from being automatically upgraded or removed.
apt-mark hold kubelet kubeadm kubectl

# Enable and start kubelet service
systemctl daemon-reload
systemctl start kubelet
systemctl enable kubelet.service