[one-users] iSCSI recipe

[christopher barry]

On Tue, 2012-07-31 at 23:23 +0200, Ruben S. Montero wrote:
> Hi,
> 
> 
> Well, I am sure you have gone through the iSCSI guide. So, I assume
> that you have properly configured your iSCSI server (that may be the
> host running oned), and hosts with password-less ssh 
> 
> 
> So roughly:
> 
> 
> Storage:
> 
> 
> 1.- Setup a System Datastore. As you plan to use iSCSI you are save
> with the ssh system datastore [1]

So, this is confusing me: <pg 40 of Setting up and Managing your Clo...>

"3.4.3      Configuration
Configuring the System Datastore
To use iSCSI drivers, you must configure the system datastore as shared.
This sytem datastore will hold
only the symbolic links to the block devices, so it will not take much
space. See more details on the
 System Datastore Guide
    It will also be used to hold context images and Disks created on the
fly, they will be created as regular
files."

This seems to contradict your statement above.

My 'assumptions' are these:

* The system datastore needs to be shared. In order to have it appear on
the hosts, I must manually export it on the frontend, mount it via nfs
on the hosts. Symlinks are all that appear in the system datastore, and
these point to block devices that have been attached to the hosts.

* Each host needs to attach to all iSCSI targets that are needed by
guests running on the host. It's not entirely clear to me if ONE handles
all that or not (assuming it does).

* a guest attaches to the symlink in the shared system datastore, but
this link actually ends up pointing to a *local* iSCSI attached block
device, so it does not become a 'bottleneck' to any IO traffic.

Does any of that make sense, or am I way off base? 


> 
> 
> 2.- Setup an iSCSI Datastore for the images as described in [2]
> 
> 
> Network:
> 
> 
> 1.- Start with a dummy network [3]
> 
> 
> This are the basic (apart from installing the opennebula software and
> the basic configuration of the hosts [4])
> 
> 
> Then just add the hosts to your OpenNebula installation [5], add some
> images (probably you can start with ttylinux from the marketplace),
> and create a template. You may want to make this first steps through
> Sunstone GUI.
> 
> 
> Cheers and good luck,
> 
> 
> Ruben
> 
> 
> 
> 
> [1] http://opennebula.org/documentation:rel3.6:system_ds
> [2] http://opennebula.org/documentation:rel3.6:iscsi_ds
> [3] http://opennebula.org/documentation:rel3.6:plan#networking
> [4] http://opennebula.org/documentation:rel3.6:plan#hosts
> [5] http://opennebula.org/documentation:rel3.6:hostsubsystem
>      http://opennebula.org/documentation:rel3.6:host_guide
> 
> 
> 
> On Mon, Jul 30, 2012 at 7:35 PM, christopher barry
> <cbarry at rjmetrics.com> wrote:
>         Greetings,
>         
>         I'm setting up a test environment and want to use iSCSI for my
>         disks.
>         I've been reading through the docs, and have made several
>         templates, but
>         it's not clear to me how to make it all work via iSCSI, and/or
>         if I need
>         to pre-setup things ahead of time or if it's all automagic.
>         
>         Is there a simple howto or recipe anywhere on how to make this
>         all work?
>         So far it's been kind of like drinking from a firehose.
>         
>         
>         Thanks,
>         -C
>         
>         _______________________________________________
>         Users mailing list
>         Users at lists.opennebula.org
>         http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
> 
> 
> 
> 
> -- 
> Ruben S. Montero, PhD
> Project co-Lead and Chief Architect
> OpenNebula - The Open Source Solution for Data Center Virtualization
> www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
>