Initial Planning

For production environments, several factors influence installation. Consider the following questions as you read through the documentation:

  • Do you install on-premises or in public/private clouds? The Installation Methods section provides more information about the cloud providers options available.

  • Which installation method do you want to use? The Installation Methods section provides some information about the quick and advanced installation methods.

  • How many pods are required in your cluster? The Sizing Considerations section provides limits for nodes and pods so you can calculate how large your environment needs to be.

  • How many hosts do you require in the cluster? The Environment Scenarios section provides multiple examples of Single Master and Multiple Master configurations.

  • Is high availability required? High availability is recommended for fault tolerance. In this situation, you might aim to use the Multiple Masters Using Native HA example as a basis for your environment.

  • Which installation type do you want to use: RPM or containerized? Both installations provide a working OKD environment, but you might have a preference for a particular method of installing, managing, and updating your services.

  • Which identity provider do you use for authentication? If you already use a supported identity provider, it is a best practice to configure OKD to use that identity provider during advanced installation.

Installation Methods

As of OKD 3.9, the quick installation method is deprecated. In a future release, it will be removed completely. In addition, using the quick installer to upgrade from version 3.7 to 3.9 is not supported.

Both the quick and advanced installation methods are supported for development and production environments. If you want to quickly get OKD up and running to try out for the first time, use the quick installer and let the interactive CLI guide you through the configuration options relevant to your environment.

For the most control over your cluster’s configuration, you can use the advanced installation method. This method is particularly suited if you are already familiar with Ansible. However, following along with the OKD documentation should equip you with enough information to reliably deploy your cluster and continue to manage its configuration post-deployment using the provided Ansible playbooks directly.

If you install initially using the quick installer, you can always further tweak your cluster’s configuration and adjust the number of hosts in the cluster using the same installer tool. If you wanted to later switch to using the advanced method, you can create an inventory file for your configuration and carry on that way.

On-premises Versus Cloud Providers

OKD can be installed on-premises or hosted on public or private clouds. Ansible playbooks can help you with automating the provisioning and installation processes. For information, see Advanced Installation.

Sizing Considerations

Determine how many nodes and pods you require for your OKD cluster. Cluster scalability correlates to the number of pods in a cluster environment. That number influences the other numbers in your setup. See Cluster Limits for the latest limits for objects in OKD.

Environment Scenarios

This section outlines different examples of scenarios for your OKD environment. Use these scenarios as a basis for planning your own OKD cluster, based on your sizing needs.

Moving from a single master cluster to multiple masters after installation is not supported.

For information on updating labels, see Updating Labels on Nodes.

Single Master and Node on One System

OKD can be installed on a single system for a development environment only. An all-in-one environment is not considered a production environment.

Single Master and Multiple Nodes

The following table describes an example environment for a single master (with etcd installed on the same host) and two nodes:

Host Name Infrastructure Component to Install

master.example.com

Master, etcd, and node

node1.example.com

Node

node2.example.com

Single Master, Multiple etcd, and Multiple Nodes

The following table describes an example environment for a single master, three etcd hosts, and two nodes:

Host Name Infrastructure Component to Install

master.example.com

Master and node

etcd1.example.com

etcd

etcd2.example.com

etcd3.example.com

node1.example.com

Node

node2.example.com

Multiple Masters Using Native HA with Co-located Clustered etcd

The following describes an example environment for three masters with co-located clustered etcd, one HAProxy load balancer, and two nodes using the native HA method:

Host Name Infrastructure Component to Install

master1.example.com

Master (clustered using native HA) and node and clustered etcd

master2.example.com

master3.example.com

lb.example.com

HAProxy to load balance API master endpoints

node1.example.com

Node

node2.example.com

Multiple Masters Using Native HA with External Clustered etcd

The following describes an example environment for three masters, one HAProxy load balancer, three external clustered etcd hosts, and two nodes using the native HA method:

Host Name Infrastructure Component to Install

master1.example.com

Master (clustered using native HA) and node

master2.example.com

master3.example.com

lb.example.com

HAProxy to load balance API master endpoints

etcd1.example.com

Clustered etcd

etcd2.example.com

etcd3.example.com

node1.example.com

Node

node2.example.com

Stand-alone Registry

You can also install OKD to act as a stand-alone registry using the OKD’s integrated registry. See Installing a Stand-alone Registry for details on this scenario.

RPM Versus Containerized

An RPM installation installs all services through package management and configures services to run within the same user space, while a containerized installation installs services using container images and runs separate services in individual containers.

See the Installing on Containerized Hosts topic for more details on configuring your installation to use containerized services.