[openstack-dev] [Neutron] auto configration of local_ip

Robert Collins robertc at robertcollins.net
Thu Jan 16 09:51:22 UTC 2014

On 16 January 2014 21:41, NOTSU Arata <notsu at virtualtech.jp> wrote:
> Hello,
> I'm trying to add a new configuration option for Neutron OVS agent. Although I've submitted a patch and it is being reviewed [1], I'm posting to this mailing list seeking opinion from a wider range.
> At present, when you deploy an environment using Neutron + OVS + GRE/VXLAN, you have to set local_ip for tunnelling in neutron agent config (typically ovs_neutron_plugin.ini). As each host has different local_ip, preparing and maintaining the config files is a cumbersome work.

It's fully automated in all the deployment systems I've looked at. I
appreciate the concern for deployers, but this is a solved problem for
us IMO.

> Anyway, with this feature, instead of setting an actual IP address to local_ip, you set some options (criteria) for choosing an IP address suitable for local_ip among IP addresses assigned to the host. At runtime, OVS agent will choose an IP address according to the criteria. You will get the same effect as you set local_ip=<the IP address> by hand.
> The question is, what criteria is appropriate for the purpose. The criteria being mentioned so far in the review are:
> 1. assigned to the interface attached to default gateway
> 2. being in the specified network (CIDR)
> 3. assigned to the specified interface
>    (1 can be considered a special case of 3)

I don't think 1 is a special case of 3 - interface based connections
are dependent on physical wiring,

How about 4. Send a few packets with a nonce in them to any of the
already meshed nodes, and those nodes can report what ip they
originated from.


Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud

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