vCenter Server backups configured via SMB using Domain-based DFS fails with error "Failed to create backup directory on backup server"

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• VCSA backups configured with domain-based namespace using SMB fails after upgrade to 7.0 Update 3h build 20395099
• Logs for backup on the vCenter report error: NT_STATUS_OBJECT_PATH_NOT_FOUND or NT_STATUS_LOGON_FAILURE
• The /var/log/vmware/applmgmt/backup.log may show:

YYYY-MM-DDTHH:MM:SS [20220825-080332-20150588] [MainProcess:PID-55662] [SMBClientStorageIOLib::_process_cmd_output:SMBClientStorageIOLib.py:97] ERROR: Command failed with error: NT_STATUS_OBJECT_PATH_NOT_FOUND
YYYY-MM-DDTHH:MM:SS [20220825-080332-20150588] [MainProcess:PID-55662] [BackupManager::CreateTargetBackupDir:BackupManager.py:111] ERROR: Failed to create backup directory Plugin error occurred. ErrCode: 151, Args: ()
YYYY-MM-DDTHH:MM:SS [3113]INFO:plugins.SMBClientStorageIOLib:Running Command: ['/usr/bin/smbclient', '//<domain>/<location>/', '-A', '/dev/shm/smbCredentialFiled5413h_c', '--send-buffer', '100M', '-t', '140', '-c', 'cd <backup-directory>/; ls']
YYYY-MM-DDTHH:MM:SS [3113]ERROR:plugins.SMBClientStorageIOLib:Command failed with error: NT_STATUS_LOGON_FAILURE

Environment

VMware vCenter Server 7.0.3

Cause

Starting with vCenter 7.0 Update 3h build 20395099, the backup architecture has been changed from 'cifs' to 'smbclient'. There have been observed limitations on samba client where kerberos DNS TXT packets that are needed for kerberos authentication is not supported.

This causes a specific failure where Domain based DFS namespace is used for target backup using VCSA File-Based Backup and Restore.

Resolution

This issue is resolved in vCenter Server 8.0 Update 1c build 22088981.
This issue is resolved in vCenter Server 7.0 Update 3o build 21958407.

Workaround:
Configure a direct path to the target server for backups:

• Log in to the vCenter server Appliance VMware Appliance Management Interface (VAMI)
• Navigate to Backup
• Configure the backup using a Fully Qualified Domain Name (FQDN) or IP Address as per the steps mentioned in Configure and Schedule Backups