While configuring the HdfsBackupRepository to use Google compute storage, I misconfigured the permissions on my bucket. Unfortunately, the exception that would have pointed me in the right direction gets squelched by the finally block in createSnapshot:
If there's a permissions issue, then the deleteDelectory is going to fail and raise another exception from the finally block, which swallows the original exception. For example:
That's merely the symptom and not the actual cause of the failure.