HDFS native driver

HDFS native driver is a plugin based on the OpenStack manila service, which uses Hadoop distributed file system (HDFS), a distributed file system designed to hold very large amounts of data, and provide high-throughput access to the data.

A manila share in this driver is a subdirectory in hdfs root directory. Instances talk directly to the HDFS storage backend with ‘hdfs’ protocol. And access to each share is allowed by user based access type, which is aligned with HDFS ACLs to support access control of multiple users and groups.

Network configuration

The storage backend and manila hosts should be in a flat network, otherwise, the L3 connectivity between them should exist.

Supported shared filesystems

• HDFS (authentication by user)

Supported Operations

• Create HDFS share

• Delete HDFS share

• Allow HDFS Share access * Only support user access type * Support level of access (ro/rw)

• Deny HDFS Share access

• Create snapshot

• Delete snapshot

• Create share from snapshot

• Extend share

Requirements

• Install HDFS package, version >= 2.4.x, on the storage backend

• To enable access control, the HDFS file system must have ACLs enabled

• Establish network connection between the manila host and storage backend

Manila driver configuration

• share_driver = manila.share.drivers.hdfs.hdfs_native.HDFSNativeShareDriver

• hdfs_namenode_ip = the IP address of the HDFS namenode, and only single

  namenode is supported now

• hdfs_namenode_port = the port of the HDFS namenode service

• hdfs_ssh_port = HDFS namenode SSH port

• hdfs_ssh_name = HDFS namenode SSH login name

• hdfs_ssh_pw = HDFS namenode SSH login password, this parameter is not

  necessary, if the following hdfs_ssh_private_key is configured

• hdfs_ssh_private_key = Path to the HDFS namenode private key to ssh login

Known Restrictions

• This driver does not support network segmented multi-tenancy model. Instead multi-tenancy is supported by the tenant specific user authentication

• Only support for single HDFS namenode in Kilo release

The manila.share.drivers.hdfs.hdfs_native Module

HDFS native protocol (hdfs) driver for manila shares.

Manila share is a directory in HDFS. And this share does not use service VM instance (share server). The instance directly talks to the HDFS cluster.

The initial version only supports single namenode and flat network.

Configuration Requirements:

To enable access control, HDFS file system must have ACLs enabled.

class HDFSNativeShareDriver(*args, **kwargs)

Bases: manila.share.driver.ExecuteMixin, manila.share.driver.ShareDriver

HDFS Share Driver.

Executes commands relating to shares. API version history:

1.0 - Initial Version

allow_access(context, share, access, share_server=None)

Allows access to the share for a given user.

check_for_setup_error()

Return an error if the prerequisites are met.

create_share(context, share, share_server=None)

Create a HDFS directory which acted as a share.

create_share_from_snapshot(context, share, snapshot, share_server=None)

Creates a snapshot.

create_snapshot(context, snapshot, share_server=None)

Creates a snapshot.

delete_share(context, share, share_server=None)

Deletes share storage.

delete_snapshot(context, snapshot, share_server=None)

Deletes a snapshot.

deny_access(context, share, access, share_server=None)

Denies the access to the share for a given user.

do_setup(context)

Do initialization while the share driver starts.

ensure_share(context, share, share_server=None)

Ensure the storage are exported.

extend_share(share, new_size, share_server=None)

Extend share storage.

get_network_allocations_number()

Returns number of network allocations for creating VIFs.

Drivers that use Nova for share servers should return zero (0) here same as Generic driver does. Because Nova will handle network resources allocation. Drivers that handle networking itself should calculate it according to their own requirements. It can have 1+ network interfaces.