Added driver minimum requirements and features doc
This document consists of a list and explanation of minimum features a driver must implement to be accepted into Manila code base. Change-Id: I12d5bf60abad4a7146d5d596f03d96bf2605cbdc
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Rodrigo Barbieri
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Copyright (c) 2015 Hitachi Data Systems
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All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License"); you may
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not use this file except in compliance with the License. You may obtain
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a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations
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under the License.
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Manila minimum requirements and features since Mitaka
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=====================================================
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In order for a driver to be accepted into Manila code base, there are certain
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minimum requirements and features that must be met, in order to ensure
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interoperability and standardized Manila functionality among cloud providers.
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At least one driver mode (:term:`DHSS` true/false)
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--------------------------------------------------
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Driver modes determine if the driver is managing network resources
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(:term:`DHSS` = true) in an automated way, in order to segregate tenants and
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private networks by making use of Manila Share Networks, or if it is up to the
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administrator to manually configure all networks (:term:`DHSS` = false) and be
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responsible for segregation, if that is desired. At least one driver mode must
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be supported. In :term:`DHSS` = true mode, Share Server entities are used, so
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the driver must implement functions that setup and teardown such servers.
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At least one file system sharing protocol
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-----------------------------------------
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In order to serve shares as a shared file system service, the driver must
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support at least one file system sharing protocol, which can be a new protocol
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or one of the currently supported protocols. The current list of supported
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protocols is as follows:
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- NFS
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- CIFS
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- GlusterFS
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- HDFS
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Access rules
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------------
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Access rules control how shares are accessible, by whom, and what the level of
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access is. Access rule operations include allowing access and denying access
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to a given share. The authentication type should be based on IP, User and/or
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Certificate. Drivers must support read-write and read-only access levels for each
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supported protocol, either through individual access rules or separate export
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locations.
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Shares
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------
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Share servicing is the core functionality of a shared file system service, so
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a driver must be able to create and delete shares.
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Share extending
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---------------
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In order to best satisfy cloud service requirements, shares must be elastic, so
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drivers must implement a share extend function that allows shares' size to be
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increased.
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Capabilities
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------------
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In order for Manila to function accordingly to the driver being used, the
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driver must provide a set of information to Manila, known as capabilities, as
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follows:
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- share_backend_name: a name for the backend;
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- driver_handles_share_servers: driver mode, whether this driver instance
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handles share servers, possible values are true or false;
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- vendor_name: driver vendor name;
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- driver_version: current driver instance version;
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- storage_protocol: list of shared file system protocols supported by this
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driver instance;
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- total_capacity_gb: total amount of storage space provided, in GB;
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- free_capacity_gb: amount of storage space available for use, in GB;
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- reserved_percentage: percentage of total storage space to be kept from being
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used.
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Certain features, if supported by drivers, need to be reported in order to
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function correctly in Manila, such as:
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- dedupe: whether the backend supports deduplication;
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- compression: whether the backend supports compressed shares;
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- thin_provisioning: whether the backend is overprovisioning shares;
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- pools: list of storage pools managed by this driver instance.
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.. note:: for more information please see http://docs.openstack.org/developer/manila/devref/capabilities_and_extra_specs.html
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Continuous Integration systems
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------------------------------
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Every driver vendor must supply a CI system that tests its drivers
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continuously for each patch submitted to OpenStack gerrit. This allows for
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better QA and quicker response and notification for driver vendors when a
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patch submitted affects an existing driver. The CI system must run all
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applicable tempest tests, test all patches Jenkins has posted +1 and post its
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test results.
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.. note:: for more information please see http://docs.openstack.org/infra/system-config/third_party.html
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Unit tests
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----------
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All drivers submitted must be contemplated with unit tests covering at least
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90% of the code, preferably 100% if possible. Unit tests must use mock
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framework and be located in-tree using a structure that mirrors the functional
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code, such as directory names and filenames. See template below:
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::
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manila/[tests/]path/to/brand/new/[test_]driver.py
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Documentation
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-------------
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Drivers submitted must provide and maintain related documentation on
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openstack-manuals, containing instructions on how to properly install and
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configure. The intended audience for this manual is cloud operators and
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administrators. Also, driver maintainers must update the Manila share features
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support mapping documentation found at
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http://docs.openstack.org/developer/manila/devref/share_back_ends_feature_support_mapping.html
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Manila optional requirements and features since Mitaka
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======================================================
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Additional to the minimum required features supported by Manila, other optional
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features can be supported by drivers as they are already supported in Manila
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and can be accessed through the API.
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Snapshots
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---------
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Share Snapshots allow for data respective to a particular point in time to be
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saved in order to be used later. In Manila API, share snapshots taken can only
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be restored by creating new shares from them, thus the original share remains
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unaffected. If Snapshots are supported by drivers, they must be
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crash-consistent.
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Managing/Unmanaging shares
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--------------------------
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If :term:`DHSS` = false mode is used, then drivers may implement a function
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that supports reading existing shares in the backend that were not created by
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Manila. After the previously existing share is registered in Manila, it is
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completely controlled by Manila and should not be handled externally anymore.
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Additionally, a function that de-registers such shares from Manila but do
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not delete from backend may also be supported.
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Share shrinking
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---------------
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Manila API supports share shrinking, thus a share can be shrunk in a similar
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way it can be extended, but the driver is responsible for making sure no data
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is compromised.
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Share ensuring
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--------------
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In some situations, such as when the driver is restarted, Manila attempts to
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perform maintenance on created shares, on the purpose of ensuring previously
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created shares are available and being serviced correctly. The driver can
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implement this function by checking shares' status and performing maintenance
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operations if needed, such as re-exporting.
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Manila experimental features since Mitaka
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=========================================
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Some features are initially released as experimental and can be accessed by
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including specific additional HTTP Request headers. Those features are not
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recommended for production cloud environments while in experimental stage.
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Share Migration
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---------------
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Shares can be migrated between different backends and pools. Manila implements
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migration using an approach that works for any manufacturer, but driver vendors
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can implement a better optimized migration function for when migration involves
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backends or pools related to the same vendor.
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Consistency Groups
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------------------
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Shares can be created within Consistency Groups in order to guarantee snapshot
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consistency of multiple shares. In order to make use of this feature, driver
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vendors must report this capability and implement its functions to work
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according to the backend, so the feature can be properly invoked through
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Manila API.
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@ -40,6 +40,7 @@ Background Concepts for Manila
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threading
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i18n
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rpc
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driver_requirements
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pool-aware-manila-scheduler
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Other Resources
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