Ubuntu Prerequisites
This document describes Ubuntu specific pre-requisites for a BareOS PMK cluster.
Operating System Install
To prepare a physical or virtual node to be part of a BareOS Kubernetes cluster:
- Install the latest version of Ubuntu 18.04.
- Update all packages to receive the latest security and bug fixes.
Manual Prerequisite
The steps below are completed automatically by the Platform9 CLI. If you would like to manually complete the prerequisites follow the steps below.
Disable Firewall Services (If Enabled)
If ufwor firewalld services are enabled, you need to disable them so that the node can communicate with other nodes in the cluster on various required ports. See Networking Prerequisites for more info on what ports are used by various Kubernetes services.
If you are using Platform9 Managed Kubernetes Free Tier, you can ignore remaining list of pre-requisites in this article. In the free tier, these are handled by the pf9ctl CLI
Install Required Dependencies and Update Ubuntu
For Ubuntu, run the following command to install required dependencies and update all installed packages.
apt-get update \ apt-get install curl uuid-runtime \ apt-get upgradeDisable any other incompatible networking services
Ensure that there is no other external / incompatible networking software running on the node as it can interfere with docker and Kubernetes networking services.
Disable Swap
Starting Kubernetes version 1.8, all Kubernetes master and worker nodes are expected to have swap disabled. This is the recommended deployment as mentioned in the Kubernetes changelog.
If swap is not disabled, kubelet service will not start on the masters and worker nodes.
Run the following command to disable swap immediately:
sudo swapoff -aRun the following command to update fstab to persist disabling swap across reboots of the node.
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstabThe above command comments out all swap entries in the /etc/fstab file.