Feature Overview

Support for thin provisioning OCP VMs on VMware vSphere IPI

Goals

Allow thin provisioning of OS disks for OCP VMs when using the VMware vSphere IPI deployment method.

1. Allow for thin provisioned OS disks for OCP VMs in VMware vSphere IPI install
2. Currently, OS disks are thick provisioned for IPI where UPI allows for thin provisioned
3. Customers tend to over provision storage and only expand when actually needed. Requiring thick provisioned nodes places undue restrictions on resources. VMs have to be storage migrated after building the cluster to change to thin provisioned.

Requirements

• Support for defining how OS disks for OCP VMs are provisioned [thick or thin]
• Working CI environment for GA support

(Optional) Use Cases

• As an administrator, I would like to define how OS disks are provisioned [thick or thin] for OpenShift VMs.

Out of Scope

Background, and strategic fit

Currently, thick provisioning of OS disks is only supported with the IPI deployment method, while UPI allows OS disks to be thick or thin provisioned. Customers tend to over provision storage and only expand when actually needed. Requiring thick provisioning for OpenShift VMs places undue restrictions on resources. VMs have to be storage migrated after building the cluster to change to thin provisioned.

Assumptions

Customer Considerations

Documentation Considerations

Questions to be addressed:

• What educational or reference material (docs) is required to support this product feature? For users/admins? Other functions (security officers, etc)?
• Does this feature have doc impact?  Yes, new install option.

• What concepts do customers need to understand to be successful in [action]? Following the documented minimum requirements and installation procedure.
• How do we expect customers will use the feature? For what purpose(s)?
• What reference material might a customer want/need to complete [action]? None.
• Is there source material that can be used as reference for the Technical Writer in writing the content? Upstream docs.