Error: VCF installer validation fails due to invalid SDDC Manager hostname

Products

• VMware SDDC Manager / VCF Installer

Issue/Introduction

• When deploying VCF 9 where an existing SDDC manager exists, the installation fails with the error
Existing SDDC Manager Configuration: Failed
Incorrect SDDC Manager hostname '<YOUR_FQDN>' provided whilst using the option to reuse VCFInstaller,expected hostname '127.0.0.1'.
• Error message indicates an "Invalid host name" or "FQDN mismatch".
• he 'Next' button may be greyed out in the installer wizard.

 

Environment

• VCF 9.x

Cause

A typographical error or improper formatting (such as uppercase characters) in the SDDC Fully Qualified Domain Name (FQDN) provided during the validation phase. The VCF installer requires RFC-compliant, lowercase FQDNs for DNS resolution and reachability checks.

Resolution

1. Review the SDDC FQDN entered in the VCF deployment parameters or configuration specification for typographical errors.
2. Ensure the hostname and FQDN are written entirely in lowercase characters.
3. Verify that the FQDN matches the DNS forward and reverse lookup records in the environment.
4. Correct any syntax errors in the JSON deployment specification if using a file upload.
5. Re-run the VCF installer validation to confirm the check completes successfully.
6. If the issue persists, verify the /etc/hosts file on the VCF Installer appliance to ensure the FQDN is not incorrectly mapped to the loopback address (127.0.0.1).