Error "Http failure response for https://vcf_installer/v1/sddcs/network-config-profiles: 504 OK" during VCF Installer step 8 to add the hosts to management domain

Products

• VMware SDDC Manager / VCF Installer
• VMware Cloud Foundation

Issue/Introduction

• VCF 9.1 Installer shows following error message during the deployment, it takes long time to verify the hosts and shows the error message.
  
  Http failure response for https://<installer.example.com>/v1/sddcs/network-config-profiles: 504 OK



  
  
• Domain Manager log on SDDC Manager shows the following log enries:
  
  /var/log/vmware/vcf/domainmanager/domainmanager.log

YYYY-MM-DDTHH:MM:SS.###+0000 DEBUG [vcf_dm, ####, ####] [c.v.evo.sddc.common.util.SshKeyScan, dm-exec-11] Getting SSH host key with algorithms rsa-sha2-512, rsa-sha2-256 from <ESX_Host>.example.com:22
YYYY-MM-DDTHH:MM:SS.###+0000 WARN [vcf_dm, ####, ####] [c.v.evo.sddc.common.util.SshKeyScan, dm-exec-22] Fail to get host key for <ESX_Host>.example.com:22 with host key algorithms rsa-sha2-512, rsa-sha2-256
YYYY-MM-DDTHH:MM:SS.###+0000 DEBUG [vcf_dm, ####, ####] [c.v.e.s.c.util.LocalProcessService, dm-exec-23] Error Output: ssh: connect to host <ESX_Host>.example.com port 22: Connection timed out


• Collecting packet capture on VCF Installer shows "TCP Retransmissions" when communicating with ESX hosts.
  
  tcpdump port 22

YYYY-MM-DD HH:MM:SS.###    <VCF Installer IP>    <ESX IP>    TCP    ##    [TCP Retransmission] ##### → 22 [SYN] Seq=0 Win=#### Len=0 MSS=#### SACK_PERM

Environment

• VCF 9.1.

Cause

This issue is observed when SSH Connection over port 22 is blocked from VCF Installer to the ESX hosts by the external firewalls.

Resolution

Allow Port 22 communication from VCF Installer appliance to the all the ESX hosts in external firewall.

Refer to VMware Ports and Protocols for more information on Port requirements.