Class HdfsBlobStore

All Implemented Interfaces:
AutoCloseable, Shutdownable

public class HdfsBlobStore extends BlobStore
Provides a HDFS file system backed blob store implementation. Note that this provides an api for having HDFS be the backing store for the blobstore, it is not a service/daemon.

We currently have NIMBUS_ADMINS and SUPERVISOR_ADMINS configuration. NIMBUS_ADMINS are given READ, WRITE and ADMIN access whereas the SUPERVISOR_ADMINS are given READ access in order to read and download the blobs form the nimbus.

The ACLs for the blob store are validated against whether the subject is a NIMBUS_ADMIN, SUPERVISOR_ADMIN or USER who has read, write or admin privileges in order to perform respective operations on the blob.

For hdfs blob store 1. The USER interacts with nimbus to upload and access blobs through NimbusBlobStore Client API. Here, unlike local blob store which stores the blobs locally, the nimbus talks to HDFS to upload the blobs. 2. The USER sets the ACLs, and the blob access is validated against these ACLs. 3. The SUPERVISOR interacts with nimbus through HdfsClientBlobStore to download the blobs. Here, unlike local blob store the supervisor interacts with HDFS directly to download the blobs. The call to HdfsBlobStore is made as a "null" subject. The blobstore gets the hadoop user and validates permissions for the supervisor.