https://DevOpsCloud.io -- Cloud Monk Losang Jinpa, Ph.D., MCSE/MCT, GitOps DevOps Engineer

Kubeadm is a command-line tool that streamlines the process of bootstrapping a minimum viable Kubernetes cluster adhering to best practices. It offers a simplified and automated approach for setting up a Kubernetes cluster that is conformant and ready for testing or running applications.

• **Best-Practice Cluster Creation:** Kubeadm follows established best practices for configuring and deploying Kubernetes components, ensuring a secure and reliable cluster setup.
• **Minimal Configuration:** It minimizes the manual configuration required, making it an accessible option for users new to Kubernetes.
• **Automation:** Kubeadm automates several steps involved in cluster creation, including setting up the control plane, joining worker nodes, and installing essential add-ons.
• **Flexibility:** While providing a “fast path,” Kubeadm also offers flexibility for customization, allowing you to adjust configurations as needed.
• **Upgradability:** Kubeadm supports cluster upgrades, helping you keep your Kubernetes environment up-to-date with new releases.

• **Ease of Use:** Kubeadm simplifies the process of bootstrapping a Kubernetes cluster, making it more accessible to beginners and less time-consuming for experienced users.
• **Best Practices:** By adhering to established best practices, Kubeadm ensures that your cluster is configured correctly and securely.
• **Automation:** It automates many of the tedious and error-prone steps involved in cluster creation, improving efficiency and reliability.
• **Flexibility:** While providing a streamlined approach, Kubeadm still offers flexibility for customization, allowing you to tailor the cluster to your specific needs.

1. **Initializing the Control Plane:**

```bash kubeadm init –pod-network-cidr=10.244.0.0/16 ```

This command initializes the Kubernetes control plane on the current node, setting up essential components like the API server, controller manager, and scheduler. It also specifies the pod network CIDR range, which is required for pod-to-pod communication within the cluster.

2. **Joining a Worker Node to the Cluster:**

```bash kubeadm join <control-plane-host>:<control-plane-port> –token <token> \

   --discovery-token-ca-cert-hash sha256:

This command joins a worker node to the cluster, connecting it to the control plane and making it available for running pods. The token, port, and certificate hash are provided during the `kubeadm init` process.

3. **Upgrading a Cluster:**

```bash kubeadm upgrade plan kubeadm upgrade apply v1.25.0 ```

These commands check for available upgrades and then upgrade the cluster to Kubernetes version 1.25.0.

• **Kubeadm Documentation:** s://kubernetes.io/docs/setup/production-environment/tools/kubeadm/(https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/)
• **Kubeadm GitHub Repository:** s://github.com/kubernetes/kubeadm(https://github.com/kubernetes/kubeadm)