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Why do we need two network interfaces for openstack nodes?

asked 2014-02-13 23:16:21 -0500

Saba gravatar image

The official online guide of openstack forces us to have two network interfaces on all the compute nodes; one to connect to the public network and another for the private network. This is the defined architecture: image description

Why is it so? Why can't we connect all the compute nodes and the controller through one public switch?

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Do we need to assign IP to both the interfaces or is it that the second network interface acts only as a bridge with no IP allotted to it....??? gravatar ( 2017-04-09 09:15:56 -0500 )edit

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answered 2014-02-13 23:41:22 -0500

dheeru gravatar image

This is reference architecture and good practice in production environment. It is suggested to segregate the internal traffic like vm to vm and other process communication. If you have only NIC on compute nodes you can still make it work the way you are describing. I have done it in lab setup. I have done all this in single box with single NIC as well. You can play around all this in Lab. For production I suggest you follow the official doc. Hope it is clear.

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I tried making it work using one NIC but got stuck in enabling the networking. I have described my problem with that here:

Saba gravatar imageSaba ( 2014-02-14 00:00:10 -0500 )edit

I am now wondering if I can define a virtual NIC (using IP aliasing) on my compute node to make it work.

Saba gravatar imageSaba ( 2014-02-14 00:00:39 -0500 )edit

@Saba, did you figure out how to deploy OpenStack using only one NIC on the nodes? I'm trying to do the same and haven't yet succeeded. Any help would be appreciated.

gkeller2 gravatar imagegkeller2 ( 2014-05-01 16:59:34 -0500 )edit

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Asked: 2014-02-13 23:16:21 -0500

Seen: 1,327 times

Last updated: Feb 13 '14