vCenter server 8 upgrade fails "Failed to connect to source appliance "new vCenter VM's name" port 443: timed out"

Products

• VMware vCenter Server

Issue/Introduction

• Upgrading vCenter Server from 7.x to 8.x fails during Stage 2 (Data Transfer).
• The vCenter Upgrade Wizard displays: Failed to connect to source appliance #### port 443: timed out.
• A secondary error may appear: Pre-upgrade check failed due the following problem: This operation is not allowed in the current state as operation 'None' is already in progress.
• Appliance management logs (/var/log/vmware/applmgmt/applmgmt.log) show connection timeouts to the source ESXi host or vCenter.

Environment

• • VMware vCenter Server 7.x
  • VMware vCenter Server 8.x

Cause

Internal firewall rules or Access Control Lists (ACLs) are blocking TCP port 443 traffic for the new temporary IP address assigned to the vCenter 8.x appliance. While port 443 may be open for the source vCenter IP, the new IP requires the same permissions to communicate with the ESXi host and source appliance during Stage 2.

Resolution

1. Identify the temporary IP address assigned to the new vCenter Server during Stage 1.
2. Ensure that TCP ports 443 and 902 are open between the temporary vCenter IP, the source vCenter IP, and the ESXi host management IP.
3. SSH to the source vCenter appliance using root credentials.
4. Test connectivity to the ESXi host and the new target IP on port 443 using the following commands:
   
   

   curl -v telnet://<Target_IP>:443
   
   nc -zv <Target_IP> 443

   
   
   
5. If the connection fails or times out, engage the network administration team to permit bidirectional traffic for the temporary IP.
6. If the "operation 'None' is already in progress" error persists after fixing the network, reset the stale import task:

   /bin/import-history reset

   
   
   
7. Restart the Stage 2 upgrade process.

Additional Information

For further steps and procedures to perform vCenter migration, covering preparation, deployment of the new vCenter Server for the upgrade and data transfer, refer to Upgrade vCenter Server 7.0 to 8.0.