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Icehouse install guide: how is external interface accessible if default gateway is on management interface?

asked 2014-05-07 05:38:22 -0500

Daniel P gravatar image

updated 2014-05-07 06:15:25 -0500

Hi, I'm following the Ubuntu 12.04/14.04 Installation Guide (Icehouse). In the section:

'Basic Environment Configuration' > 'Networking' > 'Openstack Networking (Neutron)'

It specifies that the default route passes through the management interface for the controller, network, and compute nodes. For example on the configuration page for the Controller node it says:

Configure the first interface as the management interface:

IP address:

Network mask: (or /24)

Default gateway:

Shouldn't the default gateway be on the external interface for public access from the Internet, etc?

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I loaded mentioned page in browser and search for gateway or . Cannot find any statement about
"default gateway is set to on the management interface"

dbaxps gravatar imagedbaxps ( 2014-05-07 05:52:17 -0500 )edit

No difference. It's still the same page.

dbaxps gravatar imagedbaxps ( 2014-05-07 05:58:48 -0500 )edit

@dbaxps - I re-wrote the question. The main point is that the default route passes through the management interface, not the external interface. I would have expected the gateway to be on the external interface, and hope someone can explain why it's setup this way.

Daniel P gravatar imageDaniel P ( 2014-05-07 06:18:27 -0500 )edit

I belive it's default gateway on management network and it's not supposed to forward any package to external interface. Just run route -n on management network Multi Node Neutron&VLAN System.

dbaxps gravatar imagedbaxps ( 2014-05-07 07:16:42 -0500 )edit

Would this slides be a fair for you RDO Hangout ?

dbaxps gravatar imagedbaxps ( 2014-05-07 07:26:18 -0500 )edit

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answered 2014-05-09 05:19:22 -0500

Daniel P gravatar image

After working through the networking portion of the install guide, the concepts are clearer to me now. Here's are some points for those who were a little confused as well:

  • It's useful to differentiate between user interaction with the host systems (e.g. dashboard) vs the instances.
  • User interaction with, for example dashboard, is via the management interface.
  • The external interface on the network node is the connecting point between external networks and all the virtual networks that the instances are connected to. For example, after setting up the 'demo-router' between the tenant network and the external network, I was able to ping the external facing interface on this router from the external network. The tenant facing interface on this router is the default gateway for the instances.
    • All traffic between the instances and external networks passes through this interface.
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Asked: 2014-05-07 05:38:22 -0500

Seen: 939 times

Last updated: May 09 '14