[Openstack] Neutron Network DNS Suffix via DHCP

Brian Haley haleyb.dev at gmail.com
Thu Mar 30 18:42:01 UTC 2017

On 03/28/2017 08:39 PM, Oisin O'Malley wrote:
> There was 2 separate issues to resolve;
> Firstly Nova was appending the default domain name .novalocal to the hostname it presents via the meta-data service. This can be resolved by setting dhcp_domain to an empty string in nova.conf on the Control node. For instance 'dhcp_domain='. An instances name can now be set to a FQDN which will then be passed cloud-init via the metadata server.
> Secondly, The Neutron DHCP service sets the default DNS suffix for a NIC to openstacklocal . This causes delays in DNS lookups on external DNS servers, as the wrong domain is used by default. Similarly to the above, this can be resolve by setting 'dhcp_domain=' in the Neutron DHCP config file dhcp_agent.ini. Once this is set and the DHCP service restarted, the "--domain=<DOMAIN>" parameter no longer gets set

Just an FYI that 'dhcp_domain' had been marked for deprecation and was 
finally removed in Ocata.  The new value is 'dns_domain', which lives in 
neutron.conf - the dhcp agent was changed to pick-up the new value.


> on the DHCP agents dnsmasq and no default search suffix gets passed via DHCP.
> Setting dns_domain Neutron network attribute, appears to do nothing at the moment.
> Regards,
> Oisin
>> On 03/26/2017 11:49 PM, Matthew Taylor wrote:
>> Responded off-list.
>> For the benefit of the community, would one of you care to repeat the answer on-list please?
>> Thanks!
>> -jay
>> On 27/3/17 14:22, Oisin O'Malley wrote:
>>>> Hi All,
>>>> What is the correct way to set an instances DNS search suffix via
>>>> DHCP, currently all instances receive the default openstacklocal  DNS
>>>> search space.  We are using OpenStack Newton with Neutron Networking.
>>>> Setting dhcp_domain in dhcp_agent.ini will set the value globally for
>>>> all networks, which is of little use as we host many Windows VMs with
>>>> their own domains and DNS servers. Whatever is set as dhcp_domain is
>>>> passed to Neutron DHCP Agent dnsmasq subprocess via a
>>>> --domain=<DOMAIN> parameter.
>>>> With the Neutron DNS extension enabled, you can set the a networks
>>>> dns_domain attribute with "neutron net-update --dns-name", though
>>>> this attribute appears to be ignored by the DHCP server. Can this be
>>>> used to specify the DNS search space, if so how can it be configured?
>>>> I need to be able to configure this on a per network/subnet level.
>>>> Regards,
>>>> Oisin
>>>> Oisin O'Malley
>>>> Systems Engineer
>>>> Iocane Pty Ltd
>>>> 763 South Road
>>>> Black Forest SA 5035
>>>> Office:+61 (8) 8413 1010
>>>> Fax:+61 (8) 8231 2050
>>>> Email:oisin.omalley at iocane.com.au
>>>> Web:www.iocane.com.au
> _______________________________________________
> Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
> Post to     : openstack at lists.openstack.org
> Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack

More information about the Openstack mailing list