After executing the jps command, I found that
NameNode
SecondaryNameNode
DataNode
failed to start
So check before restarting the start-dfs.sh file and the following problems occur
problem show
SecondaryNameNode DataNode
Seeing that all three have problems, I don't panic, which means that there is a problem with the configuration file.
Sure enough, in the core configuration file core-site.xml the name attribute is capitalized incorrectly
After modification, it is found that hdfs can be successfully started
