Attempting to replace ESXi host certificate fails with: "Error: a low level error has occurred"

Products

• VMware vSphere ESXi

Issue/Introduction

Attempting to replace ESXi host certificate fails with: "Error: a low level error has occurred"

Environment

ESXi 8.x

Cause

ESXi host filesystem is missing the "rui.key.incoming" file under the /etc/vmware/ssl directory. 

This "rui.key.incoming" file is a temporary private key used for the certificate replacement when a certificate request is generated through the UI. If the ESXi host is rebooted before the certificate replacement succeeds, the key is lost. 

Resolution

Generate a new certificate request through the UI, and replace the certificate before rebooting the host, ensuring the /etc/vmware/ssl/rui.key.incoming file is not lost.