3.1 Overview

Kubernetes can be deployed with more than one replica of the required master node, and automated failover to those replicas, for the purpose of providing a more scalable and resilient service.

The kubeadm package provides the kubeadm utility, a tool designed to make the deployment of a Kubernetes cluster simple. Many users may find that using this tool directly, along with the upstream documentation, provides the maximum configuration flexibility.

Oracle provides the kubeadm-ha-setup tool in an additional kubeadm-ha-setup package to help new users install and configure a high availability deployment of Kubernetes with greater ease, regardless of whether it is hosted on bare metal, on a virtual machine, or out on the cloud. The tool handles checking that basic package requirements are in place, setting proxy and firewall requirements, configuring networking, and initializing a high availability master cluster configuration for the Kubernetes environment. The tool uses the kubeadm utility, but handles many additional configuration steps that can help new users get running with minimal effort.

The instructions provided here assume that you are new to Kubernetes and are using the provided kubeadm-ha-setup tool to deploy your cluster. This tool is developed and tested at Oracle and deployment using this tool is fully supported. Alternate configurations and deployment mechanisms are untested by Oracle.

Important

High availability clusters have resilience for one master node failure. If more than one master node fails then you will need to restore you master cluster from a backup file to avoid data loss.