Cinder/blueprints/read-only-volumes

• Launchpad Entry: CinderSpec:read-only-volumes
• Created: 3 July 2013
• Contributors: Anastasia Guzikova

Summary

Note this is a big spec and where possible it is broken down into sub-specs to make it easier to share work.

User stories

The purpose is to provide the ability to attach volumes in the read-only mode.

Some examples

• unmutable volumes
• cinder as a backend for glance https://blueprints.launchpad.net/glance/+spec/glance-cinder-driver
• shared volume https://blueprints.launchpad.net/cinder/+spec/shared-volume

How can you use Read Only volumes

Create a Read Only by default volume

{
POST /v1/<tenant_id>/volumes

body:
{
    "volume": 
    {
        "status": "creating",
        '''"read_only": true,''' 
        "availability_zone": null,
        "source_volid": null,
        "display_description": null,
        "snapshot_id": null,
        "user_id": null,
        "size": 1,
        "display_name": null,
        "imageRef": null,
        "attach_status": "detached",
        "volume_type": null,
        "project_id": null,
        "metadata": {}
    }
}

Create a VolumePermission to get Read/Write permission for User or Project:

{
POST /v1/<tenant_id>/os-volume-permission

body:
{
    "volume_permission": 
    {
       "volume_id": null,
        "read_only": false,
        "project_id": null,
        "user_id": null,
    }
}

Design

Workflow is:

Read Only volumes

Add an ability to mark a volume as Read Only by default. Add an ability to create ACL for a volume.

"Blueprint: https://blueprints.launchpad.net/cinder/+spec/read-only-volumes"

Implementation

This section should describe a plan of action (the "how") to implement the changes discussed. Could include subsections like:

API Changes

• new volume permission resource

Code Changes

Code changes should include an overview of what needs to change, and in some cases even the specific details.

Migration

Include:

• data migration, if any
• redirects from old URLs to new ones, if any
• how users will be pointed to the new way of doing things, if necessary.

Test/Demo Plan

This need not be added or completed until the specification is nearing beta.

BoF agenda and discussion

Use this section to take notes during the BoF; if you keep it in the approved spec, use it for summarising what was discussed and note any options that were rejected.

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