# using 'sudo su' is not a good practice.
sudo apt update
sudo apt-get install -y apt-transport-https ca-certificates curl gpg
sudo apt install docker.io -y
sudo usermod -aG docker $USER
sudo chmod 777 /var/run/docker.sock

# Update the Version if needed
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.29/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.29/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt update && sudo apt install kubeadm kubectl kubelet -y

# VM related setup
sudo apt install containerd
sudo mkdir /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml > /dev/null
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml
echo "Enabled SystemdCgroup in containerd default config"

sudo sed -i 's/#net.ipv4.ip_forward=1/net.ipv4.ip_forward=1/' /etc/sysctl.conf
echo "IPv4 forwarding has been enabled. Bridging enabled!"

echo "br_netfilter" | sudo tee /etc/modules-load.d/k8s.conf > /dev/null
echo "br_netfilter has been added to /etc/modules-load.d/k8s.conf."

sudo swapoff -a
echo "Disabled swap"
echo "Edit /etc/fstab and disable swap if swap was eneabled"

echo "Reboot the server."

# tmux
sudo kubeadm init --control-plane-endpoint=172.27.5.14 --node-name k8s-master --pod-network-cidr=10.244.0.0/16

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

kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
kubectl get nodes
kubectl get pods -A

echo "Please wait a few minutes to get all pods running before joining any worker nodes."

sudo kubeadm reset pre-flight checks

# sudsho + paste join cmd

# sample command
#  kubeadm join 172.27.5.14:6443 --token ocks85.u2sqfn330l36ypkc \
        #--discovery-token-ca-cert-hash #sha256:939be6a03f1a9014bfbb98507086e453fc83cd109319895871d27f9772653a1d \

# Be careful if there is --control-plane in join command means one more master node 

# on master/control plane
kubeadm token create --print-join-command

# Get certificate key
openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'

# on expected new control plane
sudo kubeadm reset pre-flight checks

sudo kubeadm join <control_plane_endpoint>:<port> --token <token> --discovery-token-ca-cert-hash sha256:<discovery_token_ca_cert_hash> --control-plane --certificate-key <certificate_key>

sudo kubeadm token create --print-join-command # port 6443 need to be open