Install kubernetes using kubeadm on Debian systems

k8s-setup.sh

#!/bin/bash

set -e

# Run as root
if [ "$EUID" -ne 0 ]
  then echo "Please run as root"
  exit
fi

CRICTL_VERSION="v1.30.0"
KUBERNETES_VERSION=1.30
POSITIONAL_ARGS=()

while [[ $# -gt 0 ]]; do
  case $1 in
    -k|--kubernetes-version)
      KUBERNETES_VERSION="$2"
      shift # past argument
      shift # past value
      ;;
    -m|--mode)
      INSTALL_MODE="$2"
      shift # past argument
      shift # past value
      ;;
    -*|--*)
      echo "Unknown option $1"
      exit 1
      ;;
    *)
      POSITIONAL_ARGS+=("$1") # save positional arg
      shift # past argument
      ;;
  esac
done

set -- "${POSITIONAL_ARGS[@]}" # restore positional parameters

if [ -z "$INSTALL_MODE" ]; then
  echo "Please provide the install mode"
  exit 1
fi

if [ "$INSTALL_MODE" != "master" ] && [ "$INSTALL_MODE" != "worker" ]; then
  echo "Invalid install mode"
  exit 1
fi

# Step 1: Enable iptables Bridged Traffic on all the Nodes
cat <<EOF | tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter

# sysctl params required by setup, params persist across reboots
cat <<EOF | 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

# Apply sysctl params without reboot
sysctl --system

# Setp 2. Disable swap
swapoff -a
(crontab -l 2>/dev/null; echo "@reboot /sbin/swapoff -a") | crontab - || true

# Step 3. Install CRI-O
apt-get update -y && apt-get install -y software-properties-common gpg curl apt-transport-https ca-certificates

curl -fsSL https://pkgs.k8s.io/addons:/cri-o:/prerelease:/main/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/cri-o-apt-keyring.gpg
echo "deb [signed-by=/etc/apt/keyrings/cri-o-apt-keyring.gpg] https://pkgs.k8s.io/addons:/cri-o:/prerelease:/main/deb/ /" | tee /etc/apt/sources.list.d/cri-o.list

apt-get update -y && apt-get install -y cri-o

systemctl daemon-reload
systemctl enable crio --now && systemctl start crio.service

# install crictl

wget https://github.com/kubernetes-sigs/cri-tools/releases/download/$CRICTL_VERSION/crictl-$CRICTL_VERSION-linux-amd64.tar.gz
tar zxvf crictl-$CRICTL_VERSION-linux-amd64.tar.gz -C /usr/local/bin
rm -f crictl-$CRICTL_VERSION-linux-amd64.tar.gz

# Step 4: Install Kubeadm & Kubelet & Kubectl on all Nodes

mkdir -p /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/v$KUBERNETES_VERSION/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v$KUBERNETES_VERSION/deb/ /" | tee /etc/apt/sources.list.d/kubernetes.list

apt-get update -y && apt-get install -y kubelet kubeadm kubectl && apt-mark hold kubelet kubeadm kubectl

apt-get install -y jq
local_ip="$(ip --json addr show eth0 | jq -r '.[0].addr_info[] | select(.family == "inet") | .local')"
cat > /etc/default/kubelet << EOF
KUBELET_EXTRA_ARGS=--node-ip=$local_ip
EOF

if [ "$INSTALL_MODE" == "master" ]; then
  # On Master Node, Initialize the Control Plane
  IPADDR=$(curl ifconfig.me && echo "")
  NODENAME=$(hostname -s)
  POD_CIDR="192.168.0.0/16"

  kubeadm init --control-plane-endpoint=$IPADDR  --apiserver-cert-extra-sans=$IPADDR  --pod-network-cidr=$POD_CIDR --node-name $NODENAME
fi