Unable to register with Compute Manager while adding hosts from SDDC manager

Products

• VMware NSX
• VMware SDDC Manager

Issue/Introduction

• Below is the compute manager status from NSX manager UI.
  
• When NSX Manager tried to register the vCenter as Compute Manager, it fails with error similar to below.
  "DNS configuration for FQDN: <FQDN> is incorrect. Please fix DNS configuration and retry Resolve workflow."
• On SDDC manager, you see logs similar to below.
  Unable to configure fabric for <VCenter_FQDN> on <NSX_VIP_FQDN>. Remediation: Please check if vCenter is up and running also check if NSX Extension present in vCenter Server and delete the same. Retry the failed workflow. Reference Token: XXXXXX
• /var/log/cm-inventory/cm-inventory.log on NSX manager shows logs similar to below
  <Timerstamp> INFO task-executor-1-2 CmInventoryService 79583 FABRIC [nsx@4413 comp="nsx-manager" level="INFO" subcomp="cm-inventory"] dig command output is []

Environment

VMware NSX

Cause

CM inventory uses dig command for DNS lookup and reverse lookup. If the configured DNS server doesn't support dig, the name resolution will fail even though nslookup works causing the Compute Manager registration to fail.

Resolution

Make sure the configured DNS server supports dig.

From NSX Manager CLI, it is expected that the following dig commands work.

# dig <NSX-manager-FQDN> A +short
# dig -x  1x.x.x.21