#Kubernetes Cluster Installation - Ubuntu 22.04

#A step-by-step guide to install Kubernetes cluster on Ubuntu 22.04 using Kubeadm command .
#Master Node:  192.168.1.100 master01.tracston.com
#Worker Node:  192.168.1.101 – worker01.tracston.com
#Worker Node:  192.168.1.102 – worker02.tracston.com

#Note: Change the hostname to your domain
#Note: Taking into considaration multi master setup

 
#Set hostname and add entries in the hosts file
#Login to to master node and set hostname using hostnamectl command,

sudo hostnamectl set-hostname "master01.tracston.com"


#On the worker nodes

sudo hostnamectl set-hostname "worker01.tracston.com"  
sudo hostnamectl set-hostname "worker02.tracston.com"  

#Add the following entries in /etc/hosts file on each node

192.168.1.100  master01.tracston.com
192.168.1.101  worker01.tracston.com
192.168.1.102  worker02.tracston.com

#Disable swap & add kernel settings

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

#Load the following kernel modules on all the nodes,

sudo tee /etc/modules-load.d/containerd.conf <<EOF
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter

#Set the following Kernel parameters for Kubernetes, run beneath tee command

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

#Reload new settings
sudo sysctl --system

#Install Docker 

sudo apt install -y curl gnupg2 software-properties-common apt-transport-https ca-certificates

#Enable docker repository

sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/docker.gpg
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt update
sudo apt install -y containerd.io

#Configure containerd to start using systemd as cgroup.

containerd config default | sudo tee /etc/containerd/config.toml >/dev/null 2>&1
sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

#Restart and enable containerd service

sudo systemctl restart containerd
sudo systemctl enable containerd

# Install kubernetes 
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 update
sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

#Initialize Kubernetes cluster with Kubeadm command
sudo kubeadm init --control-plane-endpoint=master01.tracston.com
#Or to change network address range 
Kubeadm init --pod-network-cidr=192.168.0.0/16

# To work with the newly created cluster copy the configuration file to your home dir
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

# Check Cluster Status
kubectl cluster-info


#Follow the same for installation on the nodes

# Run the following command to join the node to the cluster 
sudo kubeadm join k8smaster.example.net:6443 --token xxxxxxxxxxxxxxxxxxxxxx \
   --discovery-token-ca-cert-hash sha256:0494aa7fc6ced8tj984yuetjhglkefdhjw98utw616656932ff9173c94962a36


Check the nodes status from master node 

## Install Networking Calico
kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.25.0/manifests/tigera-operator.yaml

#Download the custom resources if you wish to customize Calico

curl https://raw.githubusercontent.com/projectcalico/calico/v3.25.0/manifests/custom-resources.yaml -O
kubectl create -f custom-resources.yaml

#Check the nodes status. should be status Ready
kubectl get nodes