[K8S&RockyLinux] Building a K8S high-availability cluster tutorial based on an open source operating system.

Building a Kubernetes (K8S) high-availability cluster based on an open source operating system (such as Rocky Linux) requires a series of configurations and steps. The following is a simple tutorial to help you start building a K8S high-availability cluster:

1. Prepare the environment:

• Install the Rocky Linux operating system on each node.
• Configure a static IP address for each node.
• Make sure the nodes can communicate with each other.

1. Install Docker:

• Install Docker on each node, which will be Kubernetes' container runtime.

• Run the following command to install Docker:

  sudo dnf install docker -y
  sudo systemctl enable --now docker

1. Install Kubernetes:

• Install and configure a Kubernetes cluster using the Kubeadm tool.

• Run the following commands on all nodes to install Kubeadm, Kubelet and Kubectl:

  sudo dnf install -y kubelet kubeadm kubectl
  sudo systemctl enable --now kubelet

1. Initialize the master node:

• Execute the following command on one of the nodes to initialize the Kubernetes master node:

  sudo kubeadm init --control-plane-endpoint <LOAD_BALANCER_DNS_NAME> --upload-certs

  will  <LOAD_BALANCER_DNS_NAME>be replaced with the DNS name or IP address of the load balancer.

1. Configure the cluster network:

• Choose a web plugin (such as Calico, Flannel, or Cilium) and follow its documentation to configure it.
• Run the install command for the selected network plugin and follow its instructions to configure it.

1. Join the worker node:

• Run the output of the master node initialization command on other nodes  kubeadm jointo join them to the Kubernetes cluster.

1. Verify cluster status:

• Make sure all nodes have successfully joined the cluster by running the following command on the master node:

  kubectl get nodes

1. Configure high availability:

• Configure a load balancer to forward traffic to the Kubernetes master nodes.

• Add additional replicas of the master node by running the following command on the master node:

  kubectl scale --replicas=3 deployment.apps/kube-apiserver -n kube-system

This is a brief tutorial for building a Kubernetes high availability cluster based on Rocky Linux. Note that specific steps may vary depending on Kubernetes version, network plugin selection, and environment configuration. During the actual construction process, please refer to relevant documents and official guides, and make appropriate adjustments and configurations according to your needs.