Problem Symptom
An error message is displayed during the pre-upgrade check, indicating that the MDC configuration file of a node may be abnormal or the communication between a node and its owning MDC mode may be abnormal.
Problem Diagnosis
Log in to the faulty node and run the ps command to query the MDC process. However, the MDC process does not exist. Then check the MDC configuration file. The configuration file exists and its contents are correct.
Causes
The background MDC scheduled detection task on the FSM node detects that a new MDC process needs to be started. If the MDC process fails to be started, the rollback is performed and the active MDC process fails to delete the new MDC. As a result, the rollback fails and the configuration file that has been delivered to the MDC process are not deleted. The residual configuration file causes the pre-upgrade check to fail.
Solution
Log in to the active FSM node, switch to user dsware, and run the related dswareTool command to delete the faulty MDC node.
Set the upgrade mode.
Set the upgrade maintenance mode.
Delete the node with faulty MDC process.
Exit the upgrade maintenance mode.
Exit the upgrade mode.
Perform the pre-upgrade check again. The pre-upgrade check is successful.
