Brownfield import of vCenter into VCF Operations as a workload domain fails with error "Http failure response for https://<vcfopsfqdn>/vcf-operations/plug/sddc-76/plugin/api/v1/sddcs/imports/validations: 504 OK"

Products

• VCF Operations/Automation (formerly VMware Aria Suite)
• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• Brownfield import of the vCenter fails in the Generate SSH Known Hosts Input Data Stage:
  
  
  
  
• Login to VCF Operations UI → Navigate to Inventory → Basic View  → Expand VCF Instances  → Select the instance you require  → Click on Add Workload Domain  → Import a vCenter  → Fill in Domain Name  → Enter in the correct vCenter details to specify a vCenter → Precheck fails with the error:
  
  "Http failure response for https://<vcfopsfqdn>/vcf-operations/plug/sddc-76/plugin/api/v1/sddcs/imports/validations: 504 OK" 
  
  
• Under SDDC Manager's /var/log/vmware/vcf/domainmanager/domainmanager.log, below error log snips are found:
  
  YYYY-MM-DDTHH:MM:SS DEBUG [ucf_dn, #################,####] [c.u.e.s.c.uti1. Local ProcessService,http-nio-127.0.0.1-7200-exec-51 Error Output: ssh: connect to host <vCenterFQDN> port 22: Connection refused
YYYY-MM-DDTHH:MM:SS WARN [ucf_dn, ############,####] [c.v.evo.sddc.common.util.SshKeyScan, http-nio-127.0.0.1-7200-exec-51 Fail to get host key for <vCenterFQDN>:22 with host key algorithms rsa-sha2-512,rsa-sha2-256

Caused by: com. vmware. vcf . secure. ssh. errors. InternalVcfSshException: Fail to get host key for <ESX Host FQDN>: 22 with host key algorithms ecdsa-sha2-nistp256, ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
  
  
• Host/vCenter connectivity via Port 22 (SSH) from the SDDC Fails with below error:
  
  ssh: connect to host <vCenterFQDN/ESXi Host FQDN> port 22: Connection refused

Environment

• VCF Operations 9.x
• SDDC Manager 9.x
• vCenter
• ESXi

Cause

VCF Operations requires SSH (Port 22) access to the vCenter Server, ESXi Hosts to validate environment attributes during the import process. The error occurs if SSH is disabled on the vCenter or if a firewall blocks Port 22.

Resolution

To resolve this issue, follow the steps below:

Note: Ensure firewall rules allow bi-directional traffic on Ports 22 and 443 between SDDC Manager/VCF Operations, vCenter and ESXi Hosts.

1. Enable SSH in the vCenter:
   
   1. Log in to the vCenter Server Appliance Management Interface (VAMI) at https://####:5480.
   2. Navigate to Access and verify SSH is Enabled.
   3. From the SDDC Manager console, test connectivity to vCenter on Port 22, using following Command:
      
      curl -v telnet://<vCenter FQDN>:22
      
      
2. Enable SSH in the ESXi Host:
   
   
   1. Login to the vCenter UI.
   2. Select the ESXi Host => click on Configure and Start the SSH Service.
   3. From the SDDC Manager console, test connectivity to the ESXi Host on Port 22, using following Command:
      
      curl -v telnet://<ESXi Host FQDN>:22
      
      
3. Restart the workload domain import.

Additional Information

Enable or Disable SSH and Bash Shell Access

Enabling SSH access when vSphere Client and VAMI are unavailable