Health-check operation SDDC fails with DNS-check | Forward DNS lookup is NOT configured as expected

Products

• VMware SDDC Manager

Issue/Introduction

• DNS health check on SDDC fails with error.
• Running /opt/vmware/sddc-support/sos --dns-health also fails with error.
  DNS lookup Status : RED

"name": "sddc01.example.com: Forward DNS lookup check",
"status": "FAILED",
"message": "Forward DNS lookup is NOT configured as expected, resolved ip IPADDRESS is not equal to IPADDRESS",
"errors": "Forward DNS lookup is NOT configured as expected, resolved ip IPADDRESS is not equal to IPADDRESS"

• vcf-sos.log shows error logging similar to:

INFO [vcf_sos] [progressreporter.py::update_task_status::299::_parallel_check_nsx_dns_configuredThread0] Overall status for DNS-CHECK : COMPLETED_WITH_FAILURE
INFO [vcf_sos] [progressreporter.py::update_task_status::338::_parallel_check_nsx_dns_configuredThread0] Current Status: Task-Name: DNS-CHECK, Entity-Name: edge02.example.com: Forward DNS lookup check, Task-Status: COMPLETED
INFO [vcf_sos] [progressreporter.py::determine_progress::108::_parallel_check_nsx_dns_configuredThread0] All Tasks : {'VCF-SUMMARY': 'NOT_COMPLETED', 'DNS-CHECK:nsx.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:vcsa01.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:sddc01.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:nsx.example.com: Forwar
d DNS lookup check': 'COMPLETED', 'DNS-CHECK:esxi03.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:esxi02.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:esxi04.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:esxi01.example.com: Reverse DNS lookup check': 'COMPLETED', 'DNS-CHECK:sddc01.example.com: Forward DNS lookup check': 'FAILED', 

Environment

SDDC manager

Cause

Improperly formatted host file

Resolution

Check the sddc manager hosts file.

cat /etc/hosts

# Begin /etc/hosts (network card version)
# End /etc/hosts (network card version)
# VAMI_EDIT_BEGIN
# Generated by Studio VAMI service. Do not modify manually.

127.0.0.1   sddc01 localhost

# VAMI_EDIT_END

 

In this case as we can see loopback (127.0.01) is not associated with sddc-manager FQDN.

To fix the issue, edit the hosts file and make sure loopback entry is properly formatted like below

127.0.0.1 SDDCFQDN SHORTNAME localhost

 

Re-run the health check and make sure DNS health check is GREEN