# This script is for setting up a simple kubeadm Kubernetes cluster

## 1. Create machines

# Create 1 controle plane and 1 worker machine in your infrastructure of choice.

# This example is for AWS Ubuntu 22.04 (replace with own amis, sgids, sids)

# Create control plane instance
aws ec2 run-instances \
  --image-id ami-04a5bacc58328233d \
  --count 1 \
  --instance-type m5.large \
  --key-name arch-kube \
  --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=KubeCPNode}]' \
  --security-group-ids sg-0441b23c7207c187e \
  --subnet-id subnet-0c115241 \
  --associate-public-ip-address

# Create worker instance
aws ec2 run-instances \
  --image-id ami-04a5bacc58328233d \
  --count 1 \
  --instance-type m5.xlarge \
  --key-name arch-kube \
  --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=KubeWorkerNode}]' \
  --security-group-ids sg-0441b23c7207c187e \
  --subnet-id subnet-0c115241 \
  --associate-public-ip-address

# get the instance IPs

CP_PUBLIC_IPS=$(aws ec2 describe-instances \
  --filters "Name=tag:Name,Values=KubeCPNode" \
  --query "Reservations[].Instances[].PublicIpAddress" \
  --output text | tr '\t' ',' | tr ' ' ',')

WORKER_PUBLIC_IPS=$(aws ec2 describe-instances \
  --filters "Name=tag:Name,Values=KubeWorkerNode" \
  --query "Reservations[].Instances[].PublicIpAddress" \
  --output text | tr '\t' ',' | tr ' ' ',')

## 2. Update OS (do this on all instances)

# SSH into the instance

sudo apt update && sudo DEBIAN_FRONTEND=noninteractive apt upgrade -y && sudo reboot

## 3. Install kubeadm and its dependencies (do this on all instances)

# SSH into the instance

sudo apt install -y apt-transport-https ca-certificates curl

# Install dependencies
sudo modprobe overlay
sudo modprobe br_netfilter

# Enable required sysctl params
sudo tee /etc/modules-load.d/containerd.conf <<EOF
overlay
br_netfilter
EOF

sudo tee /etc/sysctl.d/99-kubernetes-cri.conf <<EOF
net.bridge.bridge-nf-call-iptables  = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF

sudo sysctl --system

# Install containerd
sudo apt install -y containerd

# Configure containerd
sudo mkdir -p /etc/containerd
sudo containerd config default | sudo tee /etc/containerd/config.toml

# Restart containerd
sudo systemctl restart containerd
sudo systemctl enable containerd

# Disable swap
sudo swapoff -a
sudo sed -i '/ swap / s/^/#/' /etc/fstab

# Add Kubernetes APT repository key
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.32/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

# Add Kubernetes APT repository
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.32/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update the package index
sudo apt update

# list available versions
sudo apt-cache madison kubeadm

# Install specific version (v1.32.0 — adjust patch version if needed)
KUBE_VERSION=1.32.4-1.1
sudo apt install -y kubelet=$KUBE_VERSION kubeadm=$KUBE_VERSION kubectl=$KUBE_VERSION

# Prevent them from being upgraded automatically
sudo apt-mark hold kubelet kubeadm kubectl

# Check versions
kubeadm version
kubectl version --client
kubelet --version

# Configure containerd for systemd
sudo sed -i 's/SystemdCgroup *= *false/SystemdCgroup = true/' /etc/containerd/config.toml

# Restart containerd
sudo systemctl restart containerd

## 4. Initialize the control plane (do this on the first control plane node only)

sudo kubeadm init --pod-network-cidr=192.168.0.0/16
sudo systemctl enable --now kubelet

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
source <(kubectl completion bash) # set up autocomplete in bash into the current shell, bash-completion package should be installed first.
echo "source <(kubectl completion bash)" >> ~/.bashrc # add autocomplete permanently to your bash shell.
alias k=kubectl
complete -o default -F __start_kubectl k

# Install Calico CNI
kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.29.3/manifests/calico.yaml

# Copy the join command that kubeadm generated for the worker node (see kubeadm output above)
# or you can run the following command to generate a new token
# Create a token for the worker node
# sudo kubeadm token create --print-join-command

## 5. Join a worker node

# Paste your own join command from end of step 4
sudo kubeadm join 172.20.55.87:6443 --token dr4ver.rkgx1j1f6h2zjuy0 \
	--discovery-token-ca-cert-hash sha256:d797ae33c281a9cc0911533bb3d0f152d0f91fefe804092f5658cb8f22e9aba2