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Thanks Dennis. Neutron and Nova are two different databases. Either Neutron
need to query the hostname using nova client or nova should pass in the
hostname to neutron agent.  It is doable if not impossible to get the
hostname associated with vif/port pair. It needs to be part of the code.
There are pending blue prints describing this feature. Hopefully it makes
it to Juno.

Floating IPs are another way to get around this issue, but VMs that are
closely related such as hadoop nodes should resolve fixed IP addresses and
be able to communicate over its private network.



On Mon, Apr 28, 2014 at 6:38 PM, Qin, Xiaohong <Xiaohong.Qin at emc.com> wrote:

> Murali,
>
>
>
> The actual code to invoke this dnsmasq process is in this Python code,
>
>
>
> /opt/stack/neutron/neutron/agent/linux/dhcp.py
>
>
>
> You have to play around it to make it work to suit your needs. Neutron
> does know which Vif/port associated with which VM,
>
>
>
> neutron port-list
>
>
>
> | fb607957-ea21-46a4-98ed-5801849d6fc6 |      | fa:16:3e:90:1d:1e |
> {"subnet_id": "0f49455c-a4bb-4d81-bec5-3203620200fd", "ip_address": "
> 10.0.0.2"}
>
>
>
> nova list
>
>
>
> | 8c2419a7-6927-4fce-bc64-a71789cf63b1 | demo_img1 | ACTIVE | -          |
> Running     | private=10.0.0.2, 10.10.166.171 |
>
>
>
> So the vif port for this VM (8c2419a7-6927-4fce-bc64-a71789cf63b1) is
> fb607957-ea21-46a4-98ed-5801849d6fc6.
>
>
>
> Also you can associate a floating IP address to the dnsmasq interface,
> just like you do for VM interface. One thing I noticed is that dnsmasq was
> not invoked during Neutron startup service. It was started when the first
> VM got booted up.
>
>
>
> Dennis Qin
>
>
>
> *From:* Muralidhar Balcha [mailto:muralidharb at gmail.com]
> *Sent:* Monday, April 28, 2014 3:00 PM
> *To:* Qin, Xiaohong
> *Cc:* openstack at lists.openstack.org
> *Subject:* Re: [Openstack] Neutron dnsmasq question
>
>
>
> Dennis,
>
> That does not work. Next time when a new VM is created, it replaces the
> file with default host names. I think part of the challenge is Neutron does
> not know the host name associated with the port/vif, so it fabricates a
> hostname based on the IP address. DNS lookup works for the fabricated host
> name, but  I need host entry with real host name.
>
>
>
> Also this should be part of VM provisioning logic. I don't want to
> manually edit the host file.
>
>
>
> Murali Balcha
>
>
>
> On Mon, Apr 28, 2014 at 12:08 PM, Qin, Xiaohong <Xiaohong.Qin at emc.com>
> wrote:
>
> Hi Murali,
>
>
>
> The dnsmasq process is been invoked as the following in the controller,
>
>
>
> dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces
> --interface=tap7e1faebd-1c --except-interface=lo
> --pid-file=/opt/stack/data/neutron/dhcp/90a8a84a-d4dd-4c98-bf87-492342c55b94/pid
> --dhcp-hostsfile
> =/opt/stack/data/neutron/dhcp/90a8a84a-d4dd-4c98-bf87-492342c55b94/host--dhcp-optsfile=/opt/stack/data/neutron/dhcp/90a8a84a-d4dd-4c98-bf87-492342c55b94/opts
> --leasefile-ro --dhcp-range=set:tag0,10.0.0.0,static,86400s
> --dhcp-lease-max=256 --conf-file= --domain=openstacklocal
>
>
>
> So it is consulting this file for name resolution,
>
>
>
> /opt/stack/data/neutron/dhcp/90a8a84a-d4dd-4c98-bf87-492342c55b94/host
>
>
>
> You can modify this file to map your hosts to different names as a work
> around. It might be possible to force this file to be auto generated with
> your desired options.
>
>
>
> Dennis Qin
>
>
>
> *From:* Muralidhar Balcha [mailto:muralidharb at gmail.com]
> *Sent:* Friday, April 25, 2014 5:23 PM
> *To:* openstack at lists.openstack.org
> *Subject:* [Openstack] Neutron dnsmasq question
>
>
>
> Folks,
>
> Neutron is populating dnsmasq host file with hostname something like
> "host-192-168-0-0". This is not particularly useful for me. I need name
> resolution on the host name. How can I override this behavior? I am using
> Havana and this behavior is hardcoded in the code. Is there any workaround
> for this issue?
>
>
>
> Regards,
>
>
>
> --
> Muralidhar Balcha
> 508 494 5007
>
>
>
>
>
> --
> Muralidhar Balcha
> 508 494 5007
>



-- 
Muralidhar Balcha
508 494 5007
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