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

[christopher barry]

* there is the system volume (everyone uses it)

* configured into the system volume are GRUB changes that:
	* set a cmdline variable (bubble=stateless)

* configured into the system volume are initramfs changes that:
	* if bubble == stateless
	 * mounts the context disk in early userspace
	 * gets unique data/config volume context information
	 * runs an early userspace init.sh that:
	  * mounts unique data/config volume rw
	  * unions system and data/config volume

* continues with bootup of unioned root filesystem.

I'm using Debian, so this is all fairly simple to do.


Regards,
Christopher

On Thu, 2012-09-13 at 12:32 +0200, Jaime Melis wrote:
> Hello Christopher,
> 
> 
> actually to be honest there's something I didn't quite understand
> about your use-case. What the manual procedure you followed to make
> the data/config volume to be accessible from the VMs? How is it
> shared? Or is it dynamically mounted by the VM, and if so, how?
> 
> 
> regards,
> Jaime
> 
> On Mon, Sep 10, 2012 at 5:53 PM, christopher barry
> <cbarry at rjmetrics.com> wrote:
>         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
>         >
>         >         _______________________________________________
>         >         Users mailing list
>         >         Users at lists.opennebula.org
>         >
>         http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>         >
>         >
>         >
>         >
>         >
>         > --
>         > Jaime Melis
>         > Project Engineer
>         > OpenNebula - The Open Source Toolkit for Cloud Computing
>         > www.OpenNebula.org | jmelis at opennebula.org
>         
>         
>         
> 
> 
> 
> 
> -- 
> Jaime Melis
> Project Engineer
> OpenNebula - The Open Source Toolkit for Cloud Computing
> www.OpenNebula.org | jmelis at opennebula.org
>