Managed Kubernetes Prerequisites

The article describes the prerequisites for preparing a pool of x86 (64-bit) nodes (machines) for Platform9 Managed Kubernetes.

Once the nodes are provisioned, you can create multiple Kubernetes clusters. A node can be detached from or attached to one cluster at a time.

Although a Kubernetes cluster can be as small as one node, Platform9 recommends a minimum of two or three nodes per cluster.

Platform9 supports the node operating systems, CentOS(64-bit), RHEL 7.2+ (64-bit), and Ubuntu LTS 16 (64-bit).

Prerequisites

The prerequisites can be classified into operating system related prerequisites, disk space prerequisites, RAM prerequisites, networking prerequisites, and miscellaneous prerequisites.

Following are the operating system related prerequisites.

Update CentOS/RHEL

For CentOS or RHEL 7, run the following command to update all installed packages.

yum update

Read the related document Preparing a CentOS or RHEL 7 system for running Platform9 Managed Kubernetes for further instructions on preparing a CentOS or RHEL 7 node.

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 upgrade

Disk Space Prerequisites

RAM Prerequisites

The recommended RAM requirements are a minimum of 16 GB of RAM and 1 core per 4 GB of RAM.

Networking Prerequisites

Workers must be able to receive incoming connections on the following ports. Workers must be also be able to receive incoming connections on reserved ports used by Kubernetes add-ons. For instance, an ingress controller that listens on TCP port 80.

Protocol Port Range Source Purpose
TCP 10250 Masters and Workers Kubelet API for exec and logs
TCP 10255 Masters and Workers Read-only Kubelet API
TCP 10256 Masters and Workers kubeproxy
TCP 4194 Masters and Workers cAdvisor
TCP 30000-32767 Application Clients Default port range for NodePort Services
UDP 8285 Masters and Workers flannel

Miscellaneous Prerequisite

Swap must be disabled on the host. To disable swap, refer to Disabling Swap on a Kubernetes Node.


May 06, 2016