Reply to Valeriy below and to Marc further below...

On 12/03/2014 02:39 AM, Valeriy Ponomaryov wrote:
According to (2) - yes, analog of Cinder's "manage/unmanage" is not implemented in Manila yet.

Manage/unmanage is a feature I'm very interested in seeing in Manila. I suspect it will be harder to get right in Manila than it was for Cinder, however, and more importantly, getting it right will depend a lot on the work that's going on right now to support pools and driver modes. For Manila core it won't actually be that much work but for individual drivers, implementing manage/unmanage can be a huge amount of work, so we should try to define the semantics of manage/unmanage at the project level to strike a good balance between usefulness to administrators and making it practical to implement.

On Wed, Dec 3, 2014 at 9:03 AM, Marc Koderer <m...@koderer.com <mailto:m...@koderer.com>> wrote:

    Hi Valeriy,

    thanks for feedback. My answers see below.

    Am 02.12.2014 um 16:44 schrieb Valeriy Ponomaryov
    <vponomar...@mirantis.com <mailto:vponomar...@mirantis.com>>:

    > Hello Marc,
    >
    > Here, I tried to cover mentioned use cases with "implemented or
    not" notes:
    >
    > 1) Implemented, but details of implementation are different for
    different share drivers.
    > 2) Not clear for me. If you mean possibility to mount one share
    to any amount of VMs, then yes.

    That means you have an existing shared volume in your storage
    system and import
    it to manila (like cinder manage). I guess this is not implemented
    yet.

    > 3) Nova is used only in one case - Generic Driver that uses
    Cinder volumes. So, it can be said, that Manila interface does
    allow to use "flat" network and a share driver just should have
    implementation for it. I will assume you mean usage of generic
    driver and possibility to mount shares to different machines
    except Nova VMs. - In that case network architecture should allow
    to make connection in general. If it is allowed, then should not
    be any problems with mount to any machine. Just access-allow
    operations should be performed.

    This point was actually a copy from the wiki [1]. I just removed
    the Bare-metal point
    since for me it doesn’t matter whether the infrastructure service
    is a Bare-metal machine or not.

    > 4) Access can be shared, but it is not as flexible as could be
    wanted. Owner of a share can grant access to all, and if there is
    network connectivity between user and share host, then user will
    be able to mount having provided access.

    Also a copy from the wiki.

    > 5) Manila can not remove some "mount" of some share, it can
    remove access for possibility to mount in general. So, looks like
    not implemented.
    > 6) Implemented.
    > 7) Not implemented yet.
    > 8) No "cloning", but we have snapshot-approach as for volumes in
    cinder.

    Regards
    Marc

    >
    > Regards,
    > Valeriy Ponomaryov
    > Mirantis
    >
    > On Tue, Dec 2, 2014 at 4:22 PM, Marc Koderer <m...@koderer.com
    <mailto:m...@koderer.com>> wrote:
    > Hello Manila Team,
    >
    > We identified use cases for Manila during an internal workshop
    > with our operators. I would like to share them with you and
    > update the wiki [1] since it seems to be outdated.
    >
    > Before that I would like to gather feedback and you might help me
    > with identifying things that aren’t implemented yet.
    >
    > Our list:
    >
    >  1.) Create a share and use it in a tenant
    >      Initial creation of a shared storage volume and assign it
    to several VM’s


This is the basic use case for Manila and I hope it's obvious that this works.

    >  2.) Assign an preexisting share to a VM with Manila
    >      Import an existing Share with data and it to several VM’s
    in case of
    >      migrating an existing production - services to Openstack.


Covered above.

    >  3.) External consumption of a share
    >      Accommodate and provide mechanisms for last-mile
    consumption of shares by
    >      consumers of the service that aren't mediated by Nova.


Depending on how you look at this, it either already works or it's out of scope for Manila. Now that we're looking at mount automation we may be more involved in this area, but nothing about Manila prevents the use of shares by something other than nova.

    >  4.) Cross Tenant sharing
    >      Coordinate shares across tenants


As above, this is considered out of scope, but we believe it's easy to make this work with no changes to Manila.

    >  5.) Detach a share and don’t destroy data (deactivate)
    >      Share is flagged as inactive and data are not destroyed for
    later
    >      usage or in case of legal requirements.


Can't this be achieved by simply removing all access? By default, the shares manila creates are not accessible to anyone. Access must be granted explicitly.

    >  6.) Unassign and delete data of a share
    >      Destroy entire share with all data and free space for
    further usage.


This is another core feature that already works.

    >  7.) Resize Share
    >      Resize existing and assigned share on the fly.


Similar to manage/unmanage, this is very easily to conceptually understand, but not always easy to implement, due to the vagaries of real storage systems. There are some storage systems that can easily do this (such as NetApp) but others would find it quite challenging. Interestingly, for those that have difficulty resizing shares, resizing larger is often easier than resizing smaller. Cinder has made the design choice to support expanding volumes but NOT to support shrinking volumes. This is an area where we should consider making the resize feature optional, or at least making the shrinking optional if we decide to support expanding across the board.

    >  8.) Copy existing share
    >      Copy existing share between different storage technologies


Is this an analog for the cinder migrate feature? Hopefully it's obvious that anyone can copy a share to another share with the "cp -ar" command from a host that's connected to both shares. For copying across technologies, I suspect you can't do much better than this. For copying within the same family of backends, we already have snapshot and create-share-from-snapshot, and we could add optimized migration paths if we did implement a manila-managed migration feature.

    > Regards
    > Marc
    > Deutsche Telekom
    >
    > [1]: https://wiki.openstack.org/wiki/Manila/usecases
    >
    >
    >
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    >
    >
    > --
    > Kind Regards
    > Valeriy Ponomaryov
    > www.mirantis.com <http://www.mirantis.com>
    > vponomar...@mirantis.com <mailto:vponomar...@mirantis.com>
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--
Kind Regards
Valeriy Ponomaryov
www.mirantis.com <http://www.mirantis.com>
vponomar...@mirantis.com <mailto:vponomar...@mirantis.com>


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