[Openstack] Tricky questions - 1/3 Quantum Network Object

Marco Fornaro Marco.Fornaro at huawei.com
Mon Oct 14 07:03:26 UTC 2013

Hi Jay,

I followed a different guide and installed all in a single node:
BUT I have similar problem: most of the time I cannot ping or ssh the VM that I create….sometime I can correctly create a VM…but if I reboot the system I start again to have problems
I’m still working on this issue BUT

In my opinion it’s a problem related to L3 agent: it sometime does not correctly load into the router: see item 9 of the guide


From: Jay Pipes [mailto:jaypipes at gmail.com]
Sent: den 12 oktober 2013 16:55
To: Marco Fornaro
Cc: openstack at lists.openstack.org
Subject: Re: [Openstack] Tricky questions - 1/3 Quantum Network Object

I've wondered exactly the same question -- or, put another way, why have the concept of a "subnet" at all; why not just have one or more network objects that have either a CIDR or set of IP ranges set on them, along with certain flags like "shared". The way the API is right now seems needlessly complex.
IMO, a tenant should be able to create a router for their networking, create one or more networks for their private addresses, configure the router's gateway to speak with the shared "public" network, and be done with it. The sheer number of steps that is currently necessary to make in order to set up a simple private network for a tenant's VMs is cumbersome and smells of "implementation leaking into the API".


On Thu, Oct 10, 2013 at 10:10 AM, Marco Fornaro <Marco.Fornaro at huawei.com<mailto:Marco.Fornaro at huawei.com>> wrote:
Hi All,

Some Tricky questions I ask help for (email 1 of 3):

Quantum Network object
In the “openstack networking guide”->”Using Openstack compute with Openstack”->” Advanced VM creation” (http://docs.openstack.org/grizzly/openstack-network/admin/content/advanceed_vm_creation.html) there are example boot a VM on one or more NETWORKs (meaning the quantum Network object):
nova boot --image <img> --flavor <flavor> \
--nic net-id=<net1-id> --nic net-id=<net2-id> <vm-name>

BUT if you look at the description of the network object in the API abstraction it looks like a collection of subnets (meaning the quantum object), so basically a collection of IP Addresses like<>

SO (first question): what happens in the network where I boot the VM has more than a subnet?...I suppose the VM should have a nic for EACH subnet of the network!

THEN (second question): why do I need a network object? Shouldn’t it be more practical to have just the subnet object?..why do I need to create a Network if it’s just a collection of subnets?

Thanks in advance for any help

Best Regards


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