Are you reading the log messages? I'm really struggling to understand
what is unclear given what you just included.
2019-04-04 04:27:14,029 FATAL [db-2:16000.activeMasterManager] master.HMaster:
Failed to become active master
org.apache.hadoop.security.AccessControlException: Permission denied: user=root,
access=WRITE, inode="/hbase":hduser:supergroup:drwxr-xr-x
org.apache.hadoop.security.AccessControlException: Permission denied: user=root,
access=WRITE, inode="/hbase/WALs":hduser:supergroup:drwxr-xr-x
HDFS has a notion of permissions like every other filesystem. You
started HBase as "root" (which is in itself is a bad idea), and "root"
does not have permission to write to HDFS as you've configured it. Fix
the HDFS permissions so that HBase can actually write to it.