[one-users] Do we need to mount /var/lib/one with ceph

[Ruben S. Montero]

The system datastore is accessed from the front-end to generate the context
iso. Note that you don't need to be it exported from the front-end, the
nodes and the front-end itself can mount it from an different NAS server.

The /var/lib/one contents are needed in the front-end but not by the nodes.
Just the system datastore directory.

If the VM tries to access a disk from a device that is not mounted or the
NAS server is down you'll be in trouble. However, note that context ISO is
only accessed during the boot state and the main disks of the VM are in the
ceph pool, so you'll probably be fine (but if not tested it)

Cheers


On Mon Nov 10 2014 at 3:38:14 AM Huynh Dac Nguyen <ndhuynh at spsvietnam.vn>
wrote:

> Dear Ruben,
>
> Thank you for replying
>
> So what happens if the front-end opennebula is down
> the /var/lib/one isn't mounted,only System Datastore is mounted,
> then the VM can't work, right? (the vm requires image and additional
> files)
>
> Can you explain why we don't need to export the whole /var/lib/one ?
>
> Regards,
> Ndhuynh
>
> >>> "Ruben S. Montero" <rsmontero at opennebula.org> 11/7/2014 4:52 PM
> >>>
> Hi Ndhuynh
>
> Ceph storage in OpenNebula is handled as follows:
>
>
> 1.- Image Datastores, hold disk images repository as well as images for
> running VMs in a Ceph volume
> 2.- System Datastore holds additional VM files, checkpoints, context
> disks and the like.
>
>
> If you need live-migration the easiest way is to have a shared
> filesystem for the System Datastore. You don't need to export the whole
> /var/lib/one, just the datastore directory, though.
>
>
> If you do not need to live-migrate VMs you should be ok with a ssh
> based system datastore....
>
>
> Cheers
>
>
>
>
>
>
> On Wed Nov 05 2014 at 12:09:47 PM Huynh Dac Nguyen
> <ndhuynh at spsvietnam.vn> wrote:
>
> Hi All,
>
>
> I'm researching opennebula with ceph, i saw that most of guide focus on
> using ceph as datastore - block device, right?
>
>
> Do we need to mount ceph to /var/lib/one as file system to prevent the
> opennebula frontend down expectedly?
>
>
> My script is:
>
>
> 1) Make a ceph file system : one and mount to /var/lib/one in all
> opennebula node (front-end and node)
> 2) Create a ceph block device and add to opennebula as datastore
>
>
> Is this a right way?
>
>
> Regards,
> Ndhuynh
> ndhuynh at spsvietnam.vn
>
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