Doing cross vMotion between vCenters in ELM failing with error "Compatibility check took too long to complete during vmotion"

Products

• VMware vCenter Server

Issue/Introduction

• vMotion errors or warnings appear during the compatibility check of a virtual machine when attempting to do a migration.
• Logs on source vCenter server /var/log/vmware/vpxd/vpxd.log:
  
  YYYY-MM-DDTHH:MM:SS.642-05:00 warning vpxd[04038] [Originator@6876 sub=Default] Failed to connect socket; <io_obj p:0x00007f3514d4a250, h:53, <TCP 'SOURCE VC IP : 42178'>, <TCP 'DESTINATION VC IP: 443'>>, e: 110(Connection timed out)

Environment

vCenter 6.x
vCenter 7.x
vCenter 8.x

Cause

This can be caused if there is a communication issue between the vCenters on port 443.

Resolution

Ensure connectivity between the vCenter over port 443.

To test port connectivity in VMware vCenter Server Appliance:

1. Log in as root user through the VMware vCenter Server Appliance console.
2. Run this command on the vCenter Server Appliance:

curl -v telnet://<target ip address>:<desired port number>
 
When the vCenter Server Appliance connects successfully or fails, you see output similar to:

Successful Connection:

root@vc [ ~ ]# curl -v telnet://127.0.0.1:22
* Rebuilt URL to: telnet://127.0.0.1:22/
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 22 (#0)
SSH-2.0-OpenSSH_7.8

Failed Connection:

root@vc [ ~ ]# curl -v telnet://127.0.0.1:23
* Rebuilt URL to: telnet://127.0.0.1:23/
*   Trying 127.0.0.1...
* TCP_NODELAY set
* connect to 127.0.0.1 port 23 failed: Connection refused
* Failed to connect to 127.0.0.1 port 23: Connection refused
* Closing connection 0
curl: (7) Failed to connect to 127.0.0.1 port 23: Connection refused