[one-users] Running FE as Xen dom0/domU?

[Carlos Martín Sánchez]

Hi Richard,


On Mon, May 23, 2011 at 4:09 PM, Richard Palmer
<richard.d.palmer at kcl.ac.uk>wrote:

>        The servers are all fairly powerful so I don't want to waste one
> just
>        running the FE on it. Can I run the FE code in dom0 (in Xen) and
>        also add the same server as a host to Nebula?. Or would it be better
>        to create a domU just to run the FE code in, but still add the host
>        to Nebula ?.
>

The FE can be added as a Host just fine.
We would advise to install OpenNebula in dom0, since there's no clear
advantage to an installation inside a VM. It will save you some network
configuration, and you avoid a possible performance downgrade.


You may however have some good reasons to install OpeNebula in a domU.
For instance, your servers may have an old OS and you find it difficult to
install the required dependencies. In that case a virtualized recent
distribution will be easier to set-up. Or if you have big plans for your
domU OpenNebula like migration to new HW, or High Availability setups.

In that case, keep in mind that the VM must be able to see the other Hosts
in your network, attaching its interfaces to a bridge in the private
physical interface. You should also configure an external NFS server.

       Can (or should) long running servers be managed through Nebula ? E.g.
>        a blog server. I'd like to have a single view of all the servers
>        so creating them all via Nebula would be useful, but perhaps it's
>        not really meant for this.
>

Yes, OpenNebula can and should manage all VMs, because it assumes exclusive
usage of the physical resources, and managing VMs manually may lead to IP
collisions.

Moreover, OpenNebula is well suited for long running servers. You can take
advantage of the Fault Tolerance features [1] to resubmit a crashed VM, or
even resubmit the VM in another Host if the first one fails. And, if the
server running OpenNebula fails, it will continue the monitoring and
management of the VMs when it is restarted.


       Can any requirements beyond memory and disc be specified for an
>        instance ?. E.g. must have access to tape library attached to only
>        one of the hosts.
>

You can define any placement requirement. If you need a specific Host,
REQUIREMENTS = "NAME = myhost"

or you can group some Hosts in clusters [3], and require the VM to be
deployed in any of them:
REQUIREMENTS = "CLUSTER = development"


Best regards,
Carlos.

[1] http://opennebula.org/documentation:rel2.2:ftguide
[2] http://opennebula.org/documentation:rel2.2:template#placement_section
[3] http://opennebula.org/documentation:rel2.2:cluster_guide
--
Carlos Martín, MSc
Project Major Contributor
OpenNebula - The Open Source Toolkit for Cloud Computing
www.OpenNebula.org <http://www.opennebula.org/> | cmartin at opennebula.org


On Mon, May 23, 2011 at 4:09 PM, Richard Palmer
<richard.d.palmer at kcl.ac.uk>wrote:

> Dear list,
>
>        I'm planning on a open nebula setup on some hardware we have
>        (not necessarily the hardware we *need*, but I'm hoping nebula will
>        let us make the best use of it). But I have some questions:
>
>        The servers are all fairly powerful so I don't want to waste one
> just
>        running the FE on it. Can I run the FE code in dom0 (in Xen) and
>        also add the same server as a host to Nebula?. Or would it be better
>        to create a domU just to run the FE code in, but still add the host
>        to Nebula ?.
>
>        Can (or should) long running servers be managed through Nebula ?
> E.g.
>        a blog server. I'd like to have a single view of all the servers
>        so creating them all via Nebula would be useful, but perhaps it's
>        not really meant for this.
>
>        Can any requirements beyond memory and disc be specified for an
>        instance ?. E.g. must have access to tape library attached to only
>        one of the hosts.
>
> Many thanks,
>
> Richard
>
> --
> Richard Palmer                  | Centre for E-Research
>                                |  King's College London
> richard.d.palmer at kcl.ac.uk      |
> Tel: 0207 848 1973           |
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>
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