Scripts to install latest Kubernetes on Ubuntu

Usage:

• Invocation for master node:

  ./node.sh
  export MASTER_IP="x.x.x.x"
  ./master.sh
  # do not forget to save kubeadm join command at the end of output

• Invocation for worker node:

  ./node.sh
  # after this invoke
  # sudo kubeadm join ...
  # command from master node output

node.sh contents:

#!/usr/bin/env bash
set -e

echo "Install kubectl, kubeadm, and kubelet v1.33.0"

# Prepare keyrings
sudo mkdir -p /etc/apt/keyrings
sudo apt-get install -y apt-transport-https ca-certificates curl gpg

# Kubernetes repo
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.33/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:/v1.33/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update and install Kubernetes components
sudo apt-get update -y
sudo apt-get install -y kubelet=1.33.0-1.1 kubeadm=1.33.0-1.1 kubectl=1.33.0-1.1 vim git curl wget
sudo apt-mark hold kubelet kubeadm kubectl

echo "Swap Off and Kernel Modules Setup"
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
sudo swapoff -a
sudo modprobe overlay
sudo modprobe br_netfilter

# Persist kernel modules
cat <<EOF | sudo tee /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

# Kernel parameters for Kubernetes networking
cat <<EOF | sudo tee /etc/sysctl.d/kubernetes.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

# Apply sysctl params
sudo sysctl --system

echo "Install and Configure Containerd"

# Check if containerd is already installed
if ! command -v containerd &> /dev/null
then
    echo "Containerd not found, installing..."

    # Add Docker repo key and repository
    sudo mkdir -p /etc/apt/keyrings
    curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker-archive-keyring.gpg

    echo \
    "deb [arch=amd64 signed-by=/etc/apt/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" \
    | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

    sudo apt-get update -y

    # 👇 THIS is the important line
    sudo DEBIAN_FRONTEND=noninteractive apt-get install -y \
      -o Dpkg::Options::="--force-confold" \
      --allow-downgrades --allow-change-held-packages containerd.io
else
    echo "Containerd is already installed, skipping installation."
fi

# Configure containerd permanently
sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml > /dev/null

# Modify config.toml to use SystemdCgroup
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml

sudo systemctl restart containerd
sudo systemctl enable containerd

# Enable kubelet
sudo systemctl enable kubelet

echo "Pull Kubernetes images and init cluster"

# Pull Kubernetes images
sudo kubeadm config images pull --cri-socket unix:///run/containerd/containerd.sock --kubernetes-version v1.33.0

master.sh contents:

#!/usr/bin/env bash
set -e

# Initialize cluster
sudo kubeadm init \
  --pod-network-cidr=10.244.0.0/16 \
  --upload-certs \
  --kubernetes-version=v1.33.0 \
  --control-plane-endpoint="$MASTER_IP" \
  --ignore-preflight-errors=all \
  --cri-socket unix:///run/containerd/containerd.sock

# Setup kubeconfig for user
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
export KUBECONFIG=$HOME/.kube/config

echo "Apply Calico Network"

# Apply Calico CNI
kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml

# Remove control-plane taint so pods can be scheduled
kubectl taint nodes $(hostname) node-role.kubernetes.io/control-plane:NoSchedule-