Getting started with hadoop reports an error when starting journalnode

Start journalnode and report the following error

[hadoop@salve001 ~]$ hdfs --daemon start journalnode
ERROR: Cannot set priority of journalnode process 74165
[hadoop@salve001 ~]$ 

View error log prompt

2021-02-03 10:42:05,421 ERROR org.apache.hadoop.hdfs.qjournal.server.JournalNode: Failed to start journalnode.
org.apache.hadoop.util.DiskChecker$DiskErrorException: Cannot create directory: /data1/hadoop/dfs/jn

According to the prompt, the directory cannot be created, create it manually

[root@salve001 ~]# mkdir -p  /data1/hadoop/dfs/jn

Switch hadoop user to start journalnode