[one-users] Few issues / concern about detach/attach operation of VM disks

[kiran ranjane]

Hi Carlos,

Yes, Feature 2048 does meet my requirement and I have already voted for it
in "Planing for 4.6" thread and In fact other users have also voted for
this feature, So we hope this feature should be included in 4.6 version.

Thanks
Kiran Ranjane



On Fri, Jan 17, 2014 at 6:49 PM, Carlos Martín Sánchez <
cmartin at opennebula.org> wrote:

> Hi,
>
> On Wed, Jan 15, 2014 at 4:41 PM, kiran ranjane <kiran.ranjane at gmail.com>
>  wrote:
>
> Hello Carlos,
>>
>> Thanks for the explanation, But the disk was using an image. The above
>> suggestion would be good for one or two vms, What if I deploy 10 or more
>> vms using same image (non persistent) and using a single Template?
>>
>> -- Each having their own Data-disk and each having different data in it,
>> do you think the above suggestion would work?
>> -- If I use the above procedure then I think I have to make 10 different
>> clones of the image and Also 10 different templates to deploy the VMs,
>> Which in my opinion is not feasible.
>>
>> If I am right, When I use non-persistent image a clone is created to
>> system DS while deploying the VM, if this is correct then after the vm is
>> deployed for such image it should keep the clone disk as persistent in the
>> vm. This would help in deploying number of VMs from a single template and
>> the data for that particular VM will also be persistent.
>>
>
> I think this fits the scenario described in request #2048 [1]
>
>
>> Well the VM disk should have 3 buttons
>>
>> -- attach/detach (able to attach or detach same disk to the VM)
>> -- Snapshot (Take snapshot Deferred/Hot)
>> -- Delete (Delete the disk permanently from VM)
>>
>> What do you think on this, any suggestions?
>>
>> Thanks and reagrds
>> Kiran Ranjane
>>
>
> If you could "instantiate to persistent" as described in #2048, the disk
> would use an Image and the current attach+detach operations would not
> delete the disk. I think that ticket would solve your use case, or is there
> anything else missing?
>
> Regards
>
> PS: Please reply also to the mailing list.
> [1] http://dev.opennebula.org/issues/2048
>
> --
> Carlos Martín, MSc
> Project Engineer
> OpenNebula - Flexible Enterprise Cloud Made Simple
> www.OpenNebula.org | cmartin at opennebula.org | @OpenNebula<http://twitter.com/opennebula><cmartin at opennebula.org>
>
>
> On Wed, Jan 15, 2014 at 4:41 PM, kiran ranjane <kiran.ranjane at gmail.com>wrote:
>
>> Hello Carlos,
>>
>> Thanks for the explanation, But the disk was using an image. The above
>> suggestion would be good for one or two vms, What if I deploy 10 or more
>> vms using same image (non persistent) and using a single Template?
>>
>> -- Each having their own Data-disk and each having different data in it,
>> do you think the above suggestion would work?
>> -- If I use the above procedure then I think I have to make 10 different
>> clones of the image and Also 10 different templates to deploy the VMs,
>> Which in my opinion is not feasible.
>>
>> If I am right, When I use non-persistent image a clone is created to
>> system DS while deploying the VM, if this is correct then after the vm is
>> deployed for such image it should keep the clone disk as persistent in the
>> vm. This would help in deploying number of VMs from a single template and
>> the data for that particular VM will also be persistent.
>>
>> Well the VM disk should have 3 buttons
>>
>> -- attach/detach (able to attach or detach same disk to the VM)
>> -- Snapshot (Take snapshot Deferred/Hot)
>> -- Delete (Delete the disk permanently from VM)
>>
>> What do you think on this, any suggestions?
>>
>> Thanks and reagrds
>> Kiran Ranjane
>>
>>
>>
>> On Wed, Jan 15, 2014 at 8:22 PM, Carlos Martín Sánchez <
>> cmartin at opennebula.org> wrote:
>>
>>> Hi,
>>>
>>> On Wed, Jan 15, 2014 at 2:08 PM, kiran ranjane <kiran.ranjane at gmail.com>
>>>  wrote:
>>>
>>> Hello,
>>>>
>>>> Scenario :
>>>>
>>>> -- I created a VM from a template which had 2 disk (OS, Datablock).
>>>> -- The VM was deployed properly in Running State and after that I tried
>>>> the detach operation on Datablock disk. The disk was detached correctly
>>>> without any errors but I want to attach the same disk again to the VM and
>>>> there is no such way to do it in ONE.
>>>>
>>>
>>> If the disk was volatile, it is lost. But if the disk was using an
>>> image, you can attach that same image again. So I'd say that the use case
>>> is supported, you just have to make sure that disks that may be used later
>>> need to be backed by Images.
>>>
>>> -- The disk that are listed below in Storage tab under VM should be
>>>> there even after you detach the disk from the VM so that in case we need it
>>>> back we can attach the same disk again.
>>>>
>>>
>>> This can be useful in some cases, but I'm not sure it is desirable in
>>> all situations. If the disk is using a persistent Image, I'd expect that
>>> image to be released, and ready to be used for another VM, as soon as the
>>> disk is detached.
>>>
>>> -- Also we should have the option to move/attach the data-disk of a
>>>> particular VM to any other VM.
>>>>
>>>
>>> It is possible, if the disk is backed by an Image. You can detach +
>>> detach to the other VM.
>>>
>>>
>>>> -- Now if I detach the disk the data that is stored in that particular
>>>> disk is gone. Is there a way to get it back?
>>>>
>>>
>>> If it was a volatile disk, it was deleted when it was detached.
>>>
>>>
>>> Maybe the requirement to manage persistency with Images is not
>>> intuitive, but it is the OpenNebula model. First you define the storage,
>>> and then you use it in the VMs.
>>>
>>> The only thing missing to fully support your use case may be a similar
>>> operation to detach, but less definitive. Maybe an "unmount" action could
>>> detach the disk without touching the files. I don't how useful it would be,
>>> since it can be done from the guest. What do you think of this?
>>>
>>> Best regards
>>> --
>>> Carlos Martín, MSc
>>> Project Engineer
>>> OpenNebula - Flexible Enterprise Cloud Made Simple
>>> www.OpenNebula.org | cmartin at opennebula.org | @OpenNebula<http://twitter.com/opennebula><cmartin at opennebula.org>
>>>
>>>
>>
>
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