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Shares Service

Revision as of 06:14, 29 September 2012 by Esker (talk)
  • Launchpad Entry: cinder-protocol-enhancements
  • Created: 29 Sep 2012
  • Contributors: Robert Esker, Ben Swartzlander


This document is intended to vet a concept and establish a vision for extending Cinder capabilities. More detailed blueprints (in Launchpad) and further detail in this specification will follow as necessary.


Please note the following OpenStack standard definition of terms (this glossary is repurposed from a separate blueprint and is included here for consistency and to eliminate conflict over term definitions):

disk: block-based storage read and written by a virtual machine

ephemeral disk: a disk that is stored locally on the hypervisor host; will be discarded if the VM is shut down and on failures

disk image: a sequence of bytes managed by Glance, copied to local storage by Nova to create an ephemeral disk

volume: persistent (non-ephemeral) block-based storage

block device mapping: means by which a VM launched by Nova determines disks are attached to it, including both ephemeral disks and persistent volumes


Cinder characteristics

  • The OpenStack Cinder project separates the former nova-volume into an independent service for Folsom and beyond.
  • Instances can be created from ephemeral disks or volumes presently
  • Creating an ephemeral disk is done by Nova downloading the specified disk image from Glance over HTTP, writing it to local (to the hypervisor) storage
  • Ad hoc requests for storage, whether by running instances or outside of the Nova context can be accommodated either programmatically against the Cinder API or via the python-cinderclient tool.
  • Cinder, in the initial form and as a legacy of nova-volume, provides a block only construct.

High-level proposal

Concordant with the transition from nova-volume to Cinder, the opportunity to define a broader vision for storage provisioning in OpenStack exists. An expanded vision for Cinder is both appropriate for an independent project / service in OpenStack and is also timely given a variety of user driven requirements advocating for expanded capabilities. We propose and intend to act to evolve Cinder as the canonical storage provisioning control plane in OpenStack independent of storage protocol type (whether block or file). This proposal and associated blueprints intend to, in phases, accommodate file-based storage as well. Please note that object storage is not considered in scope given well established API and mechanisms (i.e. Swift). This blueprint should be treated as an overarching / umbrella design document with separate blueprints defined for each of the phases and to also account for "whole experience" interaction.

The subordinate blueprints:

  1. File-based Volume Driver
  2. Extension of the Cinder API
  3. Extended API Reference Driver
  4. Absorption of provisioned NAS to instances
  5. Quantum Support

1) File-Based Volume Driver

Implementation of a Cinder file-based volume driver. This makes use of files as virtual block devices for mounted file systems already present at the hypervisor. The hypervisor would still present the file into the instance as a block device.


Note: the above provides generic NFS support as a reference implementation


2) Extension of the Cinder API

Extension of the Cinder API (http://api.openstack.org) to accommodate:

creation of filesystems (e.g. the create API would need to support a "protocol" & likely a permissions "mask" and "ownership" parameter) mounting filesystems (e.g. via extension of the attach API to accommodate mount semantics or possibly by creating an additional & separate "mount" call, additional provision to accommodate specifying and passing specific mount options)

creation & deletion of snapshots
unmounting filesystems
deletion of filesystems
additional vetting & support for remaining Cinder API (e.g. "get", "update", et cetera...)

Proposed API description:

Create share: CLI: cinder share-create [--snapshot_id <snapshot_id>] [--display_name <display_name>] [--display_description <display_description>] <share_protocol> <size> Note: snapshot id should be used when creating new share from snapshot is required.

Request: POST /v1/<tenant_id>/shares Body: {"snapshot_id": null, "display_name": "sh0", "proto": "cifs", "display_description": null, "size": 1}}' Successful response code: 200 Response body: '{"share": {"status": "creating", "display_name": "sh0", "share_type": "CIFS", "export_location": null, "id": "d596078a-7bfb-4977-b10d-2cf5528e708d", "size": 1}}'

Delete share: cinder share-delete <share_id>

Request: DELETE /v1/<tenant_id>/shares/<share_id> Body: None Successful response code: 200 Response body: None

List shares: cinder share-list

Request: GET /v1/<tenant_id>/shares/detail Body: None Successful response code: 200 Response body: '{"shares": [{"status": "available", "display_name": "sh1", "share_type": "NFS", "export_location": "", "id": "9d908180-f9ea-42b2-9079-88a59ade5339", "size": 1}, {"status": "available", "display_name": "sh0", "share_type": "CIFS", "export_location": "//", "id": "adcc79e4-336c-4ad2-9d38-2b65d062d971", "size": 1}]}'

Show share: cinder share-show <share_id>

Request: GET /v1/<tenant_id>/shares/<share_id> Body: None Successful response code: 200 Response body: '{"share": {"status": "available", "display_name": "sh0", "share_type": "CIFS", "export_location": "//", "id": "adcc79e4-336c-4ad2-9d38-2b65d062d971", "size": 1}}'

Allow access to share: cinder share-allow <share_id> <access_type> <access_to> Note: access_type and access_to depends from the backend. For task4 only 'ip' type is implemented.

Request: POST /v1/<tenant_id>/shares/<share_id>/action Body: {"os-access_allow": {"access_type": "ip", "access_to": "10.0.1.*"}}' Successful response code: 202 Response body: None

Deny access to share: cinder share-deny <share_id> <access_rule_id> Request: POST /v1/<tenant_id>/shares/<share_id>/action Body: {"os-access_deny": {"access_id": "20"}} Successful response code: 202 Response body: None

List share access rules: cinder share-access-list <share_id>

Request: POST /v1/<tenant_id>/shares/<share_id>/action Body: {"os-access_list": null} Successful response code: 200 Response body: '{"access_list": [{"state": "active", "id": 20, "access_type": "ip", "access_to": "10.0.0.*"}, {"state": "active", "id": 21, "access_type": "ip", "access_to": "10.0.1.*"}]}'

Create snapshot from share: cinder snapshot-create [--force <True|False>] [--display_name <display_name>] [--display_description <display_description>] <volume_id>

Request: POST /v1/<tenant_id>/snapshots Body: {"snapshot": {"display_name": "snap0", "force": false, "display_description": null, "volume_id": "7cd97eb7-6d55-418d-964c-858a6bee9d2f"}} Successful response code: 200 Response body: {"snapshot": {"status": "creating", "display_name": "snap0", "created_at": "2012-08-21 11:25:44.668712", "display_description": null, "source_type": "NFS", "volume_id": "7cd97eb7-6d55-418d-964c-858a6bee9d2f", "id": "b8531da9-de22-4df0-8e40-ffbe7d290811", "size": 1}}

Snapshot delete: cinder snapshot-delete <snapshot_id>

Request: DELETE /v1/<tenant_id>/snapshots/<snapshot_id> POST /v1/<tenant_id>/snapshots Body: {"snapshot": {"display_name": "snap0", "force": false, "display_description": null, "volume_id": "7cd97eb7-6d55-418d-964c-858a6bee9d2f"}} Successful response code: 200 Response body:

Snapshots list: cinder snapshot-list

Request: GET /v1/<tenant_id>/snapshots/detail Body: {"snapshot": {"display_name": "snap0", "force": false, "display_description": null, "volume_id": "7cd97eb7-6d55-418d-964c-858a6bee9d2f"}} Successful response code: 200 Response body: {"snapshots": [{"status": "available", "display_name": "snap0", "created_at": "2012-08-21 11:25:44", "display_description": null, "id": "b8531da9-de22-4df0-8e40-ffbe7d290811", "source_type": "NFS", "volume_id": "7cd97eb7-6d55-418d-964c-858a6bee9d2f", "os-extended-snapshot-attributes:progress": "100%", "os-extended-snapshot-attributes:project_id": "cc629b78b21142699a36ee0749749720", "size": 1}]}

3) Extended API Reference Driver

Creation of a reference Cinder driver for shared file system use under the proposed expanded API. As an example, a NetApp driver for this would be able to advertise, accept, and respond to requests for NFSv3, NFSv4, NFSv4.1 (w/ pNFS), & contemporary CIFS / SMB protocols (eg versions 2, 2.1, 3). Additional modification of python-cinderclient will be necessary to provide for the expanded array of request parameters.

4) Control of NAS Storage Mounting from Cinder

Proposal for handling injection / updates of mounts to instantiated guests operating in the Nova context. A listener / agent that could either be interacted directly or more likely poll or receive updates from instance metadata changes would represent one possible solution.

5) Quantum Support

Full consideration for cross-instance network encapsulation as part of a Quantum & Keystone integrated security model.