/kubeadm-ansible

kubeadm-ansible

Overview

Create Kubernetes Cluster with Kubeadm using ansible on CentOS 8
Kubernetes is a container orchestration system that manages containers at scale.
Kubeadm automates the installation and configuration of Kubernetes components such as the API server, Controller Manager, and Kube DNS.

Prerequisite

  • Ansible master node

    • Install python3 sudo yum install python3
    • Install git sudo yum install git
    • Install ansible sudo yum install epel-release , sudo yum install ansible
    • Set Passwordless authentication between master and hosts (kuberenetes nodes) ssh-keygen , ssh-copy-id root@IP_address
    • Add inventory file has all hosts
    [masters]
master ansible_host=node_IP  ansible_user=root

[workers]
worker1 ansible_host=node_IP ansible_user=root

  • Kubernetes master and worker nodes

    • in /etc/hosts add
    master_IP   master    masternode_hostname
worker_IP   worker    workernode_hostname

Installation Steps

  • Allow Firewall ports

    • ports needed to be opened on master node
      image
    • ports needed to be opened on worker node
      image
      note: you can also disable Firewall service instead

  • Configure Kubernetes dependencies

    These configurations are done on both master and worker Kubernetes nodes

    • Disable SELinux service
    • Disable Swapping on
    • Install CRI-O a Container runtime
    • Install Kubeadm a CLI tool that will install and configure the various components of a cluster.
    • Install kubelet a system service that runs on all nodes and handles node-level operations.
    • Install kubectl a CLI tool used for issuing commands to the cluster through its API Server.

  • Setting Up the Master Node

    • Initialize the cluster by running kubeadm init
    • Create a .kube directory at /home/cloud. This directory will hold configuration information such as the admin key files, which are required to connect to the cluster, and the cluster’s API address.
      note: cloud is a non-root user should be added before
    • Copy the /etc/kubernetes/admin.conf file that was generated from kubeadm init to your non-root cloud user’s home directory.
    • Run kubectl apply to install Flannel.