In this blog, I would like to list out points to try while facing problem of datanode not running in Hadoop cluster environment.
Basic things to checklist:
- Check for permission of files and folders.
- User and User group are properly assigned
- Check basic space requirement
- Stop all services
- Delete Hadoop Temp directory (hadoop.tmp.dir) as configured in core-site.xml
rm -Rf /home/hduser/tmp/*
- Format the name node
hadoop namenode -format
- Start hadoop Services
If you still struggle to get datanode running, follow these
- Manually, start data node and check for errors
- By this point, you will get detailed error logs which you can solve depending upon the situation.
Do let me know if you find something else, I will update in the list so others can be benefited from this blog.