openstack team mailing list archive

[Jānis Ģeņģeris <janis.gengeris@xxxxxxxxx>]

On Thu, Oct 4, 2012 at 8:23 PM, Ahmed Al-Mehdi <ahmed@xxxxxxxxxx> wrote:

>
> 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@xxxxxxxxx>
> Date: Thursday, October 4, 2012 12:37 AM
> To: Ahmed Al-Mehdi <ahmed@xxxxxxxxxx>
> Cc: Anne Gentle <anne@xxxxxxxxxxxxx>, "openstack@xxxxxxxxxxxxxxxxxxx" <
> openstack@xxxxxxxxxxxxxxxxxxx>
> 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@xxxxxxxxxx> 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.
>

I might be wrong, but I guess, that when you try to create a new instance,
the RPC call is made, and if the bridge is not on a compute node already,
it is created. For specific details you should check the source.

>
>
>
>
>
>> 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?
>
> I would recommend 3 if you are experimenting alot. One is for floating IP
net, one is for service & VM net, and one is the address that you use to
ssh into server.

Then br100 is connected with eth1.

I think this great blog entry from Mirantis will help you alot
http://www.mirantis.com/blog/openstack-networking-flatmanager-and-flatdhcpmanager/


>
>
>>
>> Thank you,
>> Ahmed.
>>
>>
>>
>> On 10/3/12 8:26 PM, "Anne Gentle" <anne@xxxxxxxxxxxxx> 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 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 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@xxxxxxxxxx> 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
>> >> 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
>> >> public_interface=br100
>> >>
>> >> I am assuming "fixed_range=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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>>
>>
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>
>
>
> --
> --janis
>
>


-- 
--janis