1. HDFS Permission Control
BSFS Implementation
&
HDFS Permission Control
EMETTEUR
00 MOIS 2011

2. General Structure
Zhe LI – BSFS Implementation
27 Feb 2013

3. Main Classes and Methods
Namespace Manager
NManager.class
NWorker.class
Namaspace.class
Metadata.class
File System Client
BlobSeerFileSystem.class
BSFSClient.class
BSFSCachedOutput/InputStream.class
BSFSOuput/InputStream.class
Functions
BSFSClient.sendRequest(): send a request to and transfer answer from server
NWorker.processData(): encapsulate app request, enqueue the request
NWorker.run(): Dequeue the request, call Namespace.process()
Namespace.process(): execute file system operation
Zhe LI – BSFS Implementation
27 Feb 2013

4. BSFSInput/OutputStream
Working Process
NManager
Nworker
Namespace
Metadata
Hadoop
BlobSeerFileSystem
BSFSClient
BSFSInput/OutputStream
BlobSeer Storage
Zhe LI – BSFS Implementation
27 Feb 2013

5. Supported Operations Zhe LI – BSFS Implementation 27 Feb 2013
MKDIR: create a directory
EXISTS: check if a directory or a file exists
ISFILE: check if the path in a request points to a file
RENAME: rename a file or a directory
BLOBID: retrieve the Blob ID where a file is stored
CREATE: create a file
STATUS: retrieve the status of a file or a directory
DELETE: delete files or directories in the file system
LISTDIR: list the content in a directory
SETSIZE: set the size of a file in its meta-data information
Zhe LI – BSFS Implementation
27 Feb 2013

6. HDFS General Structure
Hadoop
DistributedFileSystem
DFSClient
NameNode
DataNodes
Zhe LI – HDFS Permisson Control
27 Feb 2013

7. HDFS Permission Control
Permission Model
POSIX:
Users: Owner, Group, Others
Operation: Read, Write, Execute
Implemented in package: fs.permission
AccessControlException.class: exception for access control related issues.
ChomedParser.class: parse a permission mode, apply it against existing file.
FsAction.class: definition of permission modes, i.e, EXECUTE(‘‘--x’’)
FSPermission.class: a class to set file/directly permissions
PermissionParser.class: a basic class for parsing chmod or umask
PermissionStatus.class: store permission related information (user name, group name, etc.)
Zhe LI – HDFS Permisson Control
27 Feb 2013

8. Related FS Operations Working Plan Zhe LI – HDFS Permisson Control
CREATE: create a file with default permission
SET PERMISSION: set permissions to a file or a directory
MKDIR: create a directory with the given permission
STATUS: retrieve the status of a file or a directory
Working Plan
Each of the three operations should take 3 to 5 days for coding, testing and debugging.
Remove a patch on Hadoop code that changes the output path to BSFS uri, and integrate it in BSFS code. It should take 2 or 3 days for coding, testing and debugging
Zhe LI – HDFS Permisson Control
27 Feb 2013