Intro

In this [previous article]({{< ref "post/7-terraform-create-proxmox-module" >}}), I explained how to deploy 6 VMs using Terraform on Proxmox, 3 masters and 3 workers nodes, based on [cloud-init template]({{< ref "post/1-proxmox-cloud-init-vm-template" >}}).

Now that the infrastructure is ready, let’s move on to the next step: manually building a Kubernetes cluster using kubeadm.

In this post, I’ll walk through each step of the installation process of a simple Kubernetes cluster, from preparing the nodes to deploying a simple application.

I will not rely on automation tools for now, to better understand what are the steps involved in a Kubernetes cluster bootstrapping.

What is Kubernetes

Kubernetes is an open-source platform for orchestrating containers across a group of machines. It handles the deployment, scaling, and health of containerized applications, allowing you to focus on building your services rather than managing infrastructure details.

A Kubernetes cluster is made up of two main types of nodes: control plane (masters) nodes and worker nodes. The control plane is responsible for the overall management of the cluster, it makes decisions about scheduling, monitoring, and responding to changes in the system. The worker nodes are where your applications actually run, inside containers managed by Kubernetes.

In this post, we’ll manually set up a Kubernetes cluster with 3 control plane nodes (masters) and 3 workers. This structure reflects a highly available and production-like setup, even though the goal here is mainly to learn and understand how the components fit together.

Prepare the Nodes

OS-level updates and basic tools

Disabling swap and firewall adjustments

Installing container runtime (e.g., containerd)

Installing kubeadm and kubelet

Installing kubeadm on bastion

Enabling required kernel modules and sysctl settings

Initialize the Cluster

Running kubeadm init

Configuring kubectl on the bastion

Installing the CNI plugin Cilium

Join Additional Nodes

Join Masters

Creating the control-plane join command

Syncing PKI and etcd certs

Running kubeadm join on master 2 and 3

Join Workers

Generating and running the worker kubeadm join command

Verifying node status

Deploying a Sample Application

Creating a simple Deployment and Service

Exposing it via NodePort or LoadBalancer

Verifying functionality

Conclusion

Summary of the steps

When to use this manual method