VCF Conversion Failing on NSX Registration of vCenter

Products

• VMware NSX

Issue/Introduction

• When importing an existing site into VMware Cloud Foundation (VCF), the SDDC initialization process fails at the task to configure the compute manager.
• The following error is observed in the SDDC Manager /var/log/vmware/vcf/domainmanager/domainmanager.log:
  SDDC Initialize Task Configure NSX Fabric Compute Manager failed with error Unable to configure fabric for vcenter.local on <DOMAIN_REDACTED>.
• The following errors are observed in the NSX Manager /var/log/cm-inventory/cm-inventory.log, indicating that DNS queries are being routed to a local loopback interface and resulting in connection refusals: dig command output is [;; communications error to <IP_REDACTED>#53: connection refused...
ERROR task-executor-1-5 CmInventoryService... DNS is misconfigured for the ip <IP_REDACTED> -> fqdn <DOMAIN_REDACTED>
com.vmware.nsx.management.cminv.exceptions.CmPluginRegistrationFailedException: DNS configuration for FQDN: <DOMAIN_REDACTED> is incorrect. Please fix DNS configuration and retry Resolve workflow.

Environment

VCF 9.0.2

VMware NSX

Cause

• The NSX Manager appliance OS contains loopback IP addresses (such as 127.0.0.1) prioritized incorrectly in the /etc/resolv.conf file, and the /etc/resolvconf/resolv.conf.d/head file lacks the updated external name servers.
• This misconfiguration causes local reverse and forward DNS lookups to fail, which prevents the NSX Manager from registering the vCenter Server as a Compute Manager during the site import workflow.

Resolution

• To resolve this issue, flush the existing name servers from the NSX Manager configuration and re-apply the correct external DNS server addresses.

1.  Log in to the NSX Manager appliance via SSH using the admin account.
2. Clear all configured name servers:
   clear name-servers
3. Verify that the name servers have been successfully cleared (this should return no output):
   get name-servers
4. Configure the appliance with the correct DNS server IP address (replace <VALID_DNS_IP> with the actual IP):
   set name-servers <VALID_DNS_IP>
5. Verify the new name server is saved successfully:
   get name-servers
6. Log in to the appliance as root and verify the underlying OS configuration files reflect the updated DNS settings and no longer prioritize the loopback address for external queries:
   cat /etc/resolv.conf
   cat /etc/resolvconf/resolv.conf.d/head
   *(Ensure the output contains nameserver <VALID_DNS_IP> at the top of the resolver list)*
7. Return to the SDDC Manager UI and retry the failed site import initialization task.

Additional Information

• Manually editing /etc/resolv.conf is not supported and changes will not persist.
• All DNS modifications must be made using the nsx-cli to ensure the configuration is written to the database and propagated to the underlying OS files (/etc/resolvconf/resolv.conf.d/head) correctly.