After switching to using a ViewFileSystem, fs.deleteOnExit calls began failing frequently, displaying this error on failure:
16/04/21 13:56:24 INFO fs.FileSystem: Ignoring failure to deleteOnExit for path /tmp/delete_on_exit_test_123/a438afc0-a3ca-44f1-9eb5-010ca4a62d84
Since FileSystem eats the error involved, it is difficult to be sure what the error is, but I believe what is happening is that the ViewFileSystem’s child FileSystems are being close()’d before the ViewFileSystem, due to the random order ClientFinalizer closes FileSystems; so then when the ViewFileSystem tries to close(), it tries to forward the delete() calls to the appropriate child, and fails because the child is already closed.
I’m unsure how to write an actual Hadoop test to reproduce this, since it involves testing behavior on actual JVM shutdown. However, I can verify that while
regularly (~50% of the time) fails to delete the temporary directory, this code:
always successfully deletes the temporary directory on JVM shutdown.
I am not very familiar with FileSystem inheritance hierarchies, but at first glance I see two ways to fix this behavior:
1) ViewFileSystem could forward deleteOnExit calls to the appropriate child FileSystem, and not hold onto that path itself.
2) FileSystem.Cache.closeAll could first close all ViewFileSystems, then all other FileSystems.
Would appreciate any thoughts of whether this seems accurate, and thoughts (or help) on the fix.