Why does h2o require write access on hdfs root directory?

0
votes

Seeing error message

Job setup failed : org.apache.hadoop.security.AccessControlException: Permission denied: user=airflow, access=WRITE, inode="/":hdfs:hdfs:drwxr-xr-x at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:399) at ...

when trying to connect to start the h2o cluster (h2o-3.28.0.1-hdp3.1). Ie it appears that it does not like that the root hdfs dir hdfs:/// does not have write permissions for my user (and giving write access to my user via ranger does appear to fix the problem), but this seems wrong.

From past experience, I've seen this for case where the launching user does not have write permissions the their own hdfs:///user/<username> folder, but seems odd to me that h2o wants the user to have write access over the entire top level hdfs dir. Is this normal? Can I change this?

Possibly related: Finding that after starting the cluster, can't manually kill in YARN ResourceManager UI or killing the PID, rather need to go to the h2o cluster url and use the admin tab to shutdown the cluster. Any ideas why this would happen?

1
h2o

1 Answers

0
votes

Found the problem, can't find the docs / other-post-detailing-this right now, but basically, when running the hadoop jar h2odriver.jar ... command, there is an optional param called -output where you would normally put some hdfs location that h2o will write stuff (from what I can recall, this is some legacy directory that is not super important) to.

I had forgotten that this is an HDFS location and put some local temp folder's absolute path. The error was because h2o was trying to create that folder by creating the entire path in hdfs that lead to it, thus requiring being able to write from the hdfs root dir. The correct value would be something like /user/<username>.