Enabling High Availability (HA) on VCF services management small deployments is not supported in VCF 9.1.

Products

• VCF Operations

Issue/Introduction

Administrators must not attempt to enable HA on a Small deployment using any method.
This includes bypassing the UI using direct API calls or automation scripts.
Forcing this configuration will place the system into an unsupported, broken, and unrecoverable state.

Environment

VMware Cloud Foundation 9.1

Cause

This is by design. 

Resolution

Do not attempt to enable HA on small deployments in VCF 9.1. If HA is required, plan a scale up to medium size.