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Preparing Your Ubuntu Nodes for a Kubeadm Installation

16 October 2025bpd · ubuntu

Setting the Foundation for a Stable Cluster

Before you can initialize a Kubernetes cluster with `kubeadm`, you need to prepare your Ubuntu servers with the right software and system settings. The ‘Ubuntu System Administration Guide’ provides a comprehensive script to ensure your nodes are ready.

Essential Prerequisites

The guide shows that on every node (both master and workers), you must:

  1. Install a Container Runtime: Kubernetes needs a container runtime to run containers. The book demonstrates installing CRI-O, a lightweight runtime specifically for Kubernetes.
  2. Install Kubernetes Tools: You’ll add the official Kubernetes package repository and install three key components: `kubelet` (the agent that runs on each node), `kubeadm` (the cluster installation tool), and `kubectl` (the command-line tool to manage the cluster).
  3. Disable Swap: Kubernetes requires that swap memory be disabled on all nodes for performance and stability. You’ll need to run `swapoff -a` and comment out the swap line in `/etc/fstab`.
  4. Enable Kernel Modules: You must enable the `br_netfilter` module to allow Kubernetes components to see bridged traffic.

Completing these steps ensures a smooth and successful cluster installation.

This post is based from content of the book Ubuntu System adminstration guide. And the book can be found here https://www.amazon.com/stores/Mattias-Hemmingsson/author/B0FF5CQX13