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Hi Janis,

Thank you very much for your response.  I have some questions to your response which are inlined below.

Regards,
Ahmed.

From: Jānis Ģeņģeris <janis.gengeris at gmail.com<mailto:janis.gengeris at gmail.com>>
Date: Thursday, October 4, 2012 12:37 AM
To: Ahmed Al-Mehdi <ahmed at coraid.com<mailto:ahmed at coraid.com>>
Cc: Anne Gentle <anne at openstack.org<mailto:anne at openstack.org>>, "openstack at lists.launchpad.net<mailto:openstack at lists.launchpad.net>" <openstack at lists.launchpad.net<mailto:openstack at lists.launchpad.net>>
Subject: Re: [Openstack] Network IP address setting in nova.conf file

Hello Ahmed,

On Thu, Oct 4, 2012 at 9:08 AM, Ahmed Al-Mehdi <ahmed at coraid.com<mailto:ahmed at coraid.com>> wrote:
Hi Anne,

Thank you for the explanation.  A few follow-up question:

1. Is the set of IP address mentioned by fixed_range distributed over all
the Compute Nodes. E.g., a VM on Compute Node1 would get an IP address
from this range.  Another VM instance on Compute Node2 would get an IP
address from this same range.  Is that right?
I think it depends on configuration, but with standard setup as described in docs, it's done exactly as you think.

2. Pardon my ignorance, what does POC stand for?
It might be Proof Of Concept , depends on context.


3. br100 interface can be created on a Native Ubuntu server also, not
necessarily on VM in VirtualBox, right?

4. The br100 interface is only applicable to the Computer Node, not the
Controller Node, right?
http://docs.openstack.org/essex/openstack-compute/admin/content/libvirt-flat-dhcp-networking.html
This image gives good illustration about the responsibilities assigned to br100.

As I understand then br100 is interface where the VM network will be plugged in. It makes sens of having it only on compute nodes. But you can assign addresses from different subnets to the bridge, and make the instances accessible from the controller node as well.


5. The command to create the network for compute VMs - "nova-manage
network create Š." is executed on the Compute Node, right?
nova-manage works with the configured database and uses your nova.conf for getting the db dsn. It is independent from compute nodes. It depends on network configuration what happens later and where it's executed. I think nova-network service is working with all the network stuff if you are not using quantum. But I might be wrong here.

The reason I posed the question is because in the "Install and Deploy.." document, it seem  the command "nova-manage" will create the br100 interface (on the Compute Node).  How does it do that if it is executed on the Controller Node.




6. In my setup, one physical host will be the Controller Node, one
physical host is the Compute Node, and I might add another physical host
to be the Compute Node.  In this setup, what I the recommended setup for
public_interface?  Or does that depend on the number of NIC ports on the
physical host?
The public interface is where the floating IPs are handled. Better make it separate, although I have red that people have managed to make compute nodes with single interface, it might be more painful to setup.

Are you recommending the Compute Node have two interfaces (eth0 and eth1, eth0 is the public interface connected to the outside world).  The br100 interface on the Compute Node is connected to which physical interface, eth0 or eth1?



Thank you,
Ahmed.



On 10/3/12 8:26 PM, "Anne Gentle" <anne at openstack.org<mailto:anne at openstack.org>> wrote:

>Hi Ahmed -
>
>I have logged a doc bug to clear up this mismatch:
>https://bugs.launchpad.net/openstack-manuals/+bug/1061352.
>
>Appreciate you asking!
>
>Here's some explanation for each setting.
>fixed_range - fixed block of IP addresses handed out to VMs as they're
>provisioned. So these could be a 10.0.0.0/4<http://10.0.0.0/4> block if you want, or the
>192... block.
>public_interface - some say this needs to be a physical nic, but when
>you're running a POC on a VM on a laptop in VirtualBox for example, it
>can be br100. It's what DevStack defaults to. This setting indicates
>the interface nova-network uses to send the floating ip traffic on the
>correct network. So if you have nova-network on each compute node then
>yes, it belongs on the compute node.
>
>The Install/deploy guide walks through Flat DHCP as the network
>manager. If you use --network_bridge=br100 when you run the
>nova-manage network command, nova will set up the bridge for you. This
>example command uses 192.168.100.0/24<http://192.168.100.0/24> for the fixed range of IP
>addresses:
>http://docs.openstack.org/trunk/openstack-compute/install/apt/content/comp
>ute-create-network.html
>
>Hope this helps.
>
>Others on the list, feel free to correct my explanations as needed!
>Thanks,
>Anne
>
>On Wed, Oct 3, 2012 at 6:46 PM, Ahmed Al-Mehdi <ahmed at coraid.com<mailto:ahmed at coraid.com>> wrote:
>> Hello,
>>
>> I am following the steps in "OpenStack Install and Deploy ­ RedHat
>>Ubuntu"
>> (Folsom) to setup a Controller node.  The section "Configuring OpenStack
>> Compute" (
>>
>>http://docs.openstack.org/trunk/openstack-compute/install/apt/content/com
>>pute-minimum-configuration-settings.html
>> )  gives a snippet of an example of the values of parameters in the
>> nova.conf file.
>>
>> The document first lists some common settings in nova.conf file.  I am
>> highlighting the following two which I am concerned about:
>>
>> fixed_range=192.168.100.0/24<http://192.168.100.0/24>
>> public_interface=eth0
>>
>> The Document right after gives the whole content of a sample (usable)
>> nova.conf file for the Controller Node, in which the above settings are
>>set
>> as follows:
>>
>> fixed_range=10.0.0.0/24<http://10.0.0.0/24>
>> public_interface=br100
>>
>> I am assuming "fixed_range=192.168.100.0/24<http://192.168.100.0/24>" is the correct setting.
>> However, can someone please help as to the correct setting of
>> "public_interface".   And the same setting value would be applicable
>>for the
>> Compute Node, is that right?
>>
>> Thank you very much in advance.
>>
>> Regards,
>>
>> Ahmed.
>>
>>
>>
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--
--janis
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