I recently face this same issue on one of our environment.
Error:
returned 1. ERROR: Cannot set priority of zkfc process 24167
When digged more on the ZKFC Log, I found this error:
ERROR org.apache.hadoop.ha.ZKFailoverController: Unable to start failover controller. Parent znode does not exist.
I applied the solution to format ZKFC and once done I have restarted the services and it worked fine.
bin/hdfs zkfc -formatZK