Error: "SFTP is configured but not accessible.. Status: FAILED SFTP is configured but not accessible. [com.vmware.vcfms.backup.SftpUnavailable]" when backing up VCF component

Products

• VMware Cloud Foundation
• VCF Operations

Issue/Introduction

• Backup vSphere components report error:

Failed to access the system data to back up

• Error seen in services-logs/vcf-sddc-lcm/#####/vcf-sddc-build-service-sddcbuild-#########-#####/sddcbuild/console-log-##########.log

  {{"phase":"Failed", ... "precheckGroups":[{"id":"com.vmware.vcfms.backup.precheck.MultiBackupPrechecks",
"prechecks":[{"id":"com.vmware.vcfms.backup.SftpUnavailable",
"issue":{"message":{"default":"SFTP is configured but not accessible. [com.vmware.vcfms.backup.SftpUnavailable]"}},
"name":{"default":"SFTP is configured but not accessible."},"status":"FAILED"}],
"status":"FAILED"}]}}

Environment

VCF Ops: 9.1

VCF: 9.1

WS_FTP (Server or Professional): 10.0.2

 

Cause

• VCF Ops 9.1 backups only support openssh based SFTP applications

  • WS_FTP (both Server and Professional) is not based on OpenSSH

• VCF 9.1 does not support a load balancer (LB) in front of the SFTP backup server.

  • Certain LB configurations only provide a single IP/FQDN to VCF Ops upon connecting.

  • Whenever the LB changes the host key, VCF Ops sees it as a man in the middle attack and closes the connection.

Resolution

• Use an OpenSSH-based SFTP server such as OpenSSH 

• Do not use a load balancer IP/FQDN when configuring component backup under Build > Lifecycle > VCF Management > Backup & Restore > ADD BACKUP LOCATION > SFTP host FQDN or IP address