[one-users] need advice about a use-case

[christopher barry]

Thanks for looking into this Jaime.

Ideally, we would not need a template per machine, but just one for all
machines using a specific readonly base image. Not sure if that's what
you meant below or not...

I would love to be in the loop as you plan this feature.

Thanks!

-C

On Mon, 2012-09-10 at 12:20 +0200, Jaime Melis wrote:
> Hello,
> 
> 
> Short answer: can't be achieved currently, but it's an interesting use
> case and we will include it in OpenNebula 3.8 [1].
> 
> 
> Long answer:
> What you need is a DISK which will not be cloned (CLONE = NO),  will
> not be saved (SAVE = NO) and that it's marked as readonly (READONLY =
> YES). Currently there are some inconsistencies regarding these
> attributes: they are overridden by the image persistency (CLONE and
> SAVE) and type (READONLY). This renders these attributes useless in
> this scenario.
> 
> 
> We need to modify the core in order to make it work, and we will
> release it with OpenNebula 3.8. Once it's working you will be able to:
> 1) Register the base OS image
> 2) Create a new template per VM where:
> -- the base OS disk is set as DISK = [ IMAGE_ID = <ID>, SAVE = NO,
> CLONE = NO, READONLY = YES ]
> -- each one has its own CONTEXT
> 3) Once the VM boots it performs the aufs setup.
> 
> 
> [1] http://dev.opennebula.org/issues/1449
> 
> 
> Cheers,
> Jaime
> 
> On Fri, Aug 31, 2012 at 8:35 PM, christopher barry
> <cbarry at rjmetrics.com> wrote:
>         Greetings Nebulars
>         
>         I'm re-posting this, as it didn't get an answer last time. I
>         could use
>         some advise/guidance.
>         
>         Here is the scenario I'm trying to create:
>         
>         * I have a base OS image as a logical volume in an array.
>         
>         * I want all guests to boot this same image read-only - no
>         copies.
>         
>         * the initramfs in the base image will mount the context iso
>         to
>         determine it's own unique data/config disk - also a logical
>         volume.
>         
>         * this data/config volume is unioned with aufs read/write over
>         the
>         readonly base image in the initramfs, so that they together
>         form the
>         complete 'root' filesystem.
>         
>         * all disks are served via iSCSI
>         
>         
>         Each data/config disk needs to be persistent, and belong to a
>         unique
>         guest, but everyone shares the exact same read-only OS disk.
>         
>         Can anyone speak to the best method of integrating this
>         scenario with
>         ONE? I've tested this outside of ONE, but now I need to make
>         it work in
>         ONE. Would I need a separate template for each machine? I've
>         heard
>         mention of maybe needing to make the OS disk an ISO image,
>         does anyone
>         know why that would be a requirement?
>         
>         
>         Regards,
>         -C
>         
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> 
> 
> 
> 
> 
> -- 
> Jaime Melis
> Project Engineer
> OpenNebula - The Open Source Toolkit for Cloud Computing
> www.OpenNebula.org | jmelis at opennebula.org