kubeadm is the official tool for bootstrapping a production-ready Kubernetes cluster. It automates the complex setup of the control plane and worker nodes. This guide installs a single-node Kubernetes cluster using kubeadm on Ubuntu 26.04 LTS — ideal for learning or as a foundation for a multi-node cluster.

Tested and valid on:

  • Ubuntu 26.04 LTS

Prerequisites

  • Ubuntu 26.04 LTS with at least 2 CPUs and 2 GB RAM
  • A user with sudo privileges
  • Swap disabled on all nodes

Step 1 – Disable Swap

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

Step 2 – Configure Kernel Modules

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF
sudo modprobe overlay
sudo modprobe br_netfilter
cat <<EOF | sudo 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
sudo sysctl --system

Step 3 – Install containerd

sudo apt install containerd.io -y
sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml
sudo systemctl restart containerd

Step 4 – Install kubeadm, kubelet, kubectl

sudo apt install -y apt-transport-https ca-certificates curl
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/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:/v1.30/deb/ /' | 
  sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt update
sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

Step 5 – Initialize the Control Plane

sudo kubeadm init --pod-network-cidr=192.168.0.0/16

Step 6 – Configure kubectl

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

Step 7 – Install a CNI (Calico)

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.27.0/manifests/calico.yaml
kubectl get nodes

Step 8 – Allow Scheduling on Control Plane (single-node)

kubectl taint nodes --all node-role.kubernetes.io/control-plane-

Conclusion

A single-node Kubernetes cluster is running on Ubuntu 26.04 LTS. Add worker nodes by running the kubeadm join command printed during initialization. Use kubectl to deploy applications.