During a vCenter Server upgrade, the process may fail at Stage 2 with the error message: "Pre-upgrade check result: Error - The source host thumbprint is different than the provided one."
This error typically occurs due to network connectivity issues between the newly deployed vCenter Server and the source environment. Common causes include:
Option 1: Verify network connectivity:
Option 2: Check firewall settings:
Option 3: Verify DNS settings:
Note: DNS record must not be updated for the new vCenter, as it will create conflict in DNS resolution with the source vCenter.
Option 4: Use consistent deployment targets:
Use the same deployment target (ESXi host or vCenter Server) for both Stage 1 and Stage 2 of the upgrade process.
Option 5: Adjust DRS settings:
Manual" for the cluster where the new vCenter Server is being deployed.Option 6: Regenerate SSL certificates if needed:
If certificate issues persist, consider regenerating SSL certificates for the involved systems. For more information refer Using vSphere Certificate Manager to Replace SSL Certificates
Option 7: If all the above options are normal, then retry the upgrade from Stage1.
Redeploy the target VCSA appliance and use a vCenter Server address as source and target VM destinations
Option 8: In the logs it is mentioned the right thumbprint which is my case was the host thumbprint XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX but it needs to be in the colons format (XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX) so you can create it manually from logs or follow the next steps.
To get the host thumbprint and apply them on both Source and Target (Newly deployed node) vCenters do the following:
cd /etc/vmware/ssl path and type the below command: openssl x509 -in rui.crt -fingerprint
3. Confirm that the thumbprint on both vCenters if it matches the hosts they reside on by using below command.
install-parameter upgrade.source.ssl.thumbprint
4. Take the fingerprint output in step 2 and add it to this command then run it from vCenter's SSH (apply the thumbprint of each vCenter regarding to the hosts it resides on):
install-parameter upgrade.source.ssl.thumbprint -s "Thumb_Print"
(Example: install-parameter upgrade.source.ssl.thumbprint -s "XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX")
5. Re-run the pre-checks and proceed further.
Option 9: Engage network team:
If network issues are suspected, involve your network team to investigate and resolve any potential routing or firewall problems.