Re: [openstack-dev] [Neutron][dns]What the meaning of "dns_assignment" and "dns_name"?

[Miguel Lavalle]

Hi Neil,

You are correct about dns_name and dns_assignment.

Prior to adding this feature to Neutron, all your ports were getting
implicitly what I named "dns_assignment". It was created by the the DHCP
agent and pushed to the dnsmasq instance associated with the port's
network. This implicit  dns_assignment was of the form 'hostname' =
'host-10.65.0.4', 'ip_address' = '10.65.0.4', 'fqdn' =
'host-10-65-0-4.opentacklocal'. It wasn't a dictionary. It was just a
record in the files that the DHCP agent uses to control the behavior of the
dnsmasq instances and it was never seen (for the most part) by the users.
All I did was to make this "dns_assignment" explicit, give it a name as an
attribute in the API, give the user visibility of it and give the user
control of the names associated with it through the API (moving its
generation to the Neutron server as a consequence). This is turn is
allowing me to implement  on the Nova side functionality to assign to ports
associated with an instance the hostname of said instance, per this spec:
https://review.openstack.org/#/c/90150/

Thanks for your interest ion this feature.

Regards

Miguel


On Fri, Nov 6, 2015 at 4:28 AM, Neil Jerram 
wrote:

> Hi Miguel,
>
> I’ve just been looking at this, and have deduced the following summary of
> the new dns_name and dns_assignment fields:
>
> - dns_name is a simple name, like 'vm17'. It is a writable port field, and
> gets combined with a dns_domain that is specified elsewhere.
>

> - dns_assignment is a server-generated read-only field‎, holding a list of
> dicts like {'hostname': 'vm17', 'ip_address': '10.65.0.4', 'fqdn': '
> vm17.datcon.co.uk'}.
>
> Can you confirm whether that's correct?
>
> What is the reason (or requirement) for dns_assignment being able to
> specify hostname and fqdn on a per-IP-address basis?  Does it ever make
> sense for a VM to associate a different hostname with different NICs or IP
> addresses?
>
> Many thanks,
> Neil
>
>
>
> From: Miguel Lavalle [mailto:mig...@mlavalle.com]
> Sent: 14 October 2015 04:22
> To: OpenStack Development Mailing List (not for usage questions) <
> openstack-dev@lists.openstack.org>
> Subject: Re: [openstack-dev] [Neutron][dns]What the meaning of
> "dns_assignment" and "dns_name"?
>
> Zhi Chang,
> Thank you for your questions. We are in the process of integrating Neutron
> and Nova with an external DNS service, using Designate as the reference
> implementation. This integration is being achieved in 3 steps. What you are
> seeing is the result of only the first one. These steps are:
> 1) Internal DNS integration in Neutron, which merged recently:
> https://review.openstack.org/#/c/200952/. As you may know, Neutron has an
> internal DHCP / DNS service based on dnsmasq for each virtual network that
> you create. Previously, whenever you created a port on a given network,
> your port would get a default host name in dnsmasq of the form
> 'host-xx-xx-xx-xx.openstacklocal.", where xx-xx-xx-xx came from the port's
> fixed ip address "xx.xx.xx.xx" and "openstacklocal" is the default domain
> used by Neutron. This name was generated by the dhcp agent. In the above
> mentioned patchset, we are moving the generation of these dns names to the
> Neutron server, with the intent of allowing the user to specify it. In
> order to do that, you need to enable it by defining in neutron.conf the
> 'dns_domain' parameter with a value different to the default
> 'openstacklocal'. Once you do that, you can create or update a port and
> assign a value to its 'dns_name' attribute. Why is this useful? Please read
> on.
>
> 2) External DNS integration in Neutron. The patchset is being worked now:
> https://review.openstack.org/#/c/212213/. The functionality implemented
> here allows Neutron to publish the dns_name associated with a floating ip
> under a domain in an external dns service. We are using Designate as the
> reference implementation, but the idea is that in the future other DNS
> services can be integrated.. Where does the dns name and domain of the
> floating ip come from? It can come from 2 sources. Source number 1 is the
> floating ip itself, because in this patchset we are adding a dns_name and a
> dns_domain attributes to it. If the floating ip doesn't have a dns name and
> domain associated with it, then they can come from source number 2: the
> port that the floating ip is associated with (as explained in point 1,
> ports now can have a dns_name attribute) and the port's network, since this
> patchset adds dns_domain to networks.
> 3) Integration of Nova with Neutron's DNS. I have started the
> implementation of this and over the next few days will push the code to
> Gerrit for first review. When an instance is created, nova will request to
> Neutron the creation of the corresponding port specifying the instance's
> hostname in the port's 'dns_name' attribute (as explained in point 1). If
> the network where that port lives has a dns_domain 

Re: [openstack-dev] [Neutron][dns]What the meaning of "dns_assignment" and "dns_name"?

[Neil Jerram]

Hi Miguel,

I’ve just been looking at this, and have deduced the following summary of the 
new dns_name and dns_assignment fields:

- dns_name is a simple name, like 'vm17'. It is a writable port field, and gets 
combined with a dns_domain that is specified elsewhere. 

- dns_assignment is a server-generated read-only field‎, holding a list of 
dicts like {'hostname': 'vm17', 'ip_address': '10.65.0.4', 'fqdn': 
'vm17.datcon.co.uk'}.

Can you confirm whether that's correct?

What is the reason (or requirement) for dns_assignment being able to specify 
hostname and fqdn on a per-IP-address basis?  Does it ever make sense for a VM 
to associate a different hostname with different NICs or IP addresses?

Many thanks,
Neil



From: Miguel Lavalle [mailto:mig...@mlavalle.com] 
Sent: 14 October 2015 04:22
To: OpenStack Development Mailing List (not for usage questions) 

Subject: Re: [openstack-dev] [Neutron][dns]What the meaning of "dns_assignment" 
and "dns_name"?

Zhi Chang,
Thank you for your questions. We are in the process of integrating Neutron and 
Nova with an external DNS service, using Designate as the reference 
implementation. This integration is being achieved in 3 steps. What you are 
seeing is the result of only the first one. These steps are:
1) Internal DNS integration in Neutron, which merged recently: 
https://review.openstack.org/#/c/200952/. As you may know, Neutron has an 
internal DHCP / DNS service based on dnsmasq for each virtual network that you 
create. Previously, whenever you created a port on a given network, your port 
would get a default host name in dnsmasq of the form 
'host-xx-xx-xx-xx.openstacklocal.", where xx-xx-xx-xx came from the port's 
fixed ip address "xx.xx.xx.xx" and "openstacklocal" is the default domain used 
by Neutron. This name was generated by the dhcp agent. In the above mentioned 
patchset, we are moving the generation of these dns names to the Neutron 
server, with the intent of allowing the user to specify it. In order to do 
that, you need to enable it by defining in neutron.conf the 'dns_domain' 
parameter with a value different to the default 'openstacklocal'. Once you do 
that, you can create or update a port and assign a value to its 'dns_name' 
attribute. Why is this useful? Please read on.

2) External DNS integration in Neutron. The patchset is being worked now: 
https://review.openstack.org/#/c/212213/. The functionality implemented here 
allows Neutron to publish the dns_name associated with a floating ip under a 
domain in an external dns service. We are using Designate as the reference 
implementation, but the idea is that in the future other DNS services can be 
integrated.. Where does the dns name and domain of the floating ip come from? 
It can come from 2 sources. Source number 1 is the floating ip itself, because 
in this patchset we are adding a dns_name and a dns_domain attributes to it. If 
the floating ip doesn't have a dns name and domain associated with it, then 
they can come from source number 2: the port that the floating ip is associated 
with (as explained in point 1, ports now can have a dns_name attribute) and the 
port's network, since this patchset adds dns_domain to networks.
3) Integration of Nova with Neutron's DNS. I have started the implementation of 
this and over the next few days will push the code to Gerrit for first review. 
When an instance is created, nova will request to Neutron the creation of the 
corresponding port specifying the instance's hostname in the port's 'dns_name' 
attribute (as explained in point 1). If the network where that port lives has a 
dns_domain associated with it (as explained in point 2) and you assign a 
floating ip to the port, your instance's hostname will be published in the 
external dns service.
To make it clearer, here I walk you through an example that I executed in my 
devstack: http://paste.openstack.org/show/476210/
As mentioned above, we also allow the dns_name and dns_domain to be published 
in the external dns to be defined at the floating ip level. The reason for this 
is that we envision a use case where the name and ip address made public in the 
dns service are stable, regardless of the nova instance associated with the 
floating ip.
If you are attending the upcoming Tokyo summit, you could attend the following 
talk for further information:  
http://openstacksummitoctober2015tokyo.sched.org/event/5cbdd5fb4a6d080f93a5f321ff59009c#.Vh3KMZflRz2
 Looking forward to see you there!

Hope this answers your questions
Best regards
Miguel Lavalle

On Tue, Oct 13, 2015 at 9:58 AM, Zhi Chang  wrote:
Hi, all
    I install the latest devstack and create a vm by nova. I get the port's 
info which created by Neutron. I'm confused that what the meaning of column 
"dns_assignment" and column "dns_name".
    First, column "dns_assignment" is a read-only attribute. What is it used 
for? I think that this column is useless 

Re: [openstack-dev] [Neutron][dns]What the meaning of"dns_assignment" and "dns_name"?

[Daniel Comnea]

Hi,

While #1 does improve things further it doesn't cover the use case where
you have 2 tenants and you would like to have the VMs spun up different dns
domains.

I suspect this was intentionally left out?

Dani

On Wed, Oct 14, 2015 at 11:39 PM, Miguel Lavalle 
wrote:

> Zhi Chang,
>
> You got all the steps correct. A few clarifications:
>
>
>1. Address 104.130.78.191 is the ip address of my devstack VM. When
>you deploy Designate in devstack, it starts an instance of PowerDNS for
>you. Designate then pushes all its zones and records to that PowerDNS
>instance. When I say "dig my-instance.my-example.org @104.130.78.191"
>I am instructing dig to direct the lookup to the DNS server @
>104.130.78.191: in other words, my PowerDNS instance
>2. For you to be able to execute the same steps in your devstack, you
>need:
>   - The code in patchset https://review.openstack.org/#/c/212213/
>   - The modified nova code in nova/network/neutronv2/api.py that I
>   haven't pushed to Gerrit yet
>   - Configure a few parameters in /etc/neutron/neutron.conf
>   - Migrate the Neutron database, because I added columns to a couple
>   of tables
>
> Let me know if you want to try this in your devstack. If the answer is
> yes, I will let you know when I push the nova change to gerrit. At that
> point, I will provide detailed steps to accomplish point 2 above
>
> Best regards
>
>
> Miguel
>
>
> On Wed, Oct 14, 2015 at 12:53 AM, Zhi Chang 
> wrote:
>
>> Hi, Miguel
>> Thank you so much for your reply. You are so patient!
>> After reading your reply, I still have some questions to ask you. :-)
>> Below, is my opinion about the
>> http://paste.openstack.org/show/476210/, please read it and tell me
>> whether I was right.
>> (1). Define a DNS domain
>> (2). Update a network's "dns_domain" attribute to the DNS domain
>> which defined in the step1
>> (3). Create a VM in this network. The instance's port will assign
>> instance's hostname to it's dns_name attribute
>> (4). Create a floating IP for this VM
>> (5). In Designate, there will be generate a new A record. This record
>> is a link between floating IP and dns_name+domain_name. Just like your
>> record: deec921d-b630-4479-8932-c5ec7c530820 | A |
>> my-instance.my-example.org. | 172.24.4.3
>>   (6). I am don't understand where the IP address "104.130.78.191" comes
>> from. I think this address is a public DNS, just like 8.8.8.8. Does it
>> right?
>>(7). I can dig "my-instance.my-example.org." by a public DNS. And the
>> result is the floating IP.
>>
>> Does my understanding was right?
>>
>> Hope For Your Reply.
>> Thanks
>> Zhi Chang
>>
>> -- Original --
>> *From: * "Miguel Lavalle";
>> *Date: * Wed, Oct 14, 2015 11:22 AM
>> *To: * "OpenStack Development Mailing List (not for usage questions)"<
>> openstack-dev@lists.openstack.org>;
>> *Subject: * Re: [openstack-dev] [Neutron][dns]What the meaning
>> of"dns_assignment" and "dns_name"?
>>
>> Zhi Chang,
>>
>> Thank you for your questions. We are in the process of integrating
>> Neutron and Nova with an external DNS service, using Designate as the
>> reference implementation. This integration is being achieved in 3 steps.
>> What you are seeing is the result of only the first one. These steps are:
>>
>> 1) Internal DNS integration in Neutron, which merged recently:
>> https://review.openstack.org/#/c/200952/. As you may know, Neutron has
>> an internal DHCP / DNS service based on dnsmasq for each virtual network
>> that you create. Previously, whenever you created a port on a given
>> network, your port would get a default host name in dnsmasq of the form
>> 'host-xx-xx-xx-xx.openstacklocal.", where xx-xx-xx-xx came from the port's
>> fixed ip address "xx.xx.xx.xx" and "openstacklocal" is the default domain
>> used by Neutron. This name was generated by the dhcp agent. In the above
>> mentioned patchset, we are moving the generation of these dns names to the
>> Neutron server, with the intent of allowing the user to specify it. In
>> order to do that, you need to enable it by defining in neutron.conf the
>> 'dns_domain' parameter with a value different to the default
>> 'openstacklocal'. Once you do that, you can create or update a port and
>> assign a value to its 'dns_name' attribute. Why is this useful? Please read
>> on.
>>
>> 2) External DNS integration in Neutron. The patchset is being worked now:
>> https://review.openstack.org/#/c/212213/. The functionality implemented
>> here allows Neutron to publish the dns_name associated with a floating ip
>> under a domain in an external dns service. We are using Designate as the
>> reference implementation, but the idea is that in the future other DNS
>> services can be integrated.. Where does the dns name and domain of the
>> floating ip come from? It can come from 2 sources. Source number 1 is 

Re: [openstack-dev] [Neutron][dns]What the meaning of"dns_assignment" and "dns_name"?

[Zhi Chang]

Hi, Miguel
Thank you so much for your reply. You are so patient!
After reading your reply, I still have some questions to ask you. :-)
Below, is my opinion about the http://paste.openstack.org/show/476210/, 
please read it and tell me whether I was right.
(1). Define a DNS domain
(2). Update a network's "dns_domain" attribute to the DNS domain which 
defined in the step1
(3). Create a VM in this network. The instance's port will assign 
instance's hostname to it's dns_name attribute
(4). Create a floating IP for this VM
(5). In Designate, there will be generate a new A record. This record is a 
link between floating IP and dns_name+domain_name. Just like your record: 
deec921d-b630-4479-8932-c5ec7c530820 | A| my-instance.my-example.org. | 
172.24.4.3
  (6). I am don't understand where the IP address "104.130.78.191" comes from. 
I think this address is a public DNS, just like 8.8.8.8. Does it right?
   (7). I can dig "my-instance.my-example.org." by a public DNS. And the result 
is the floating IP.


Does my understanding was right?


Hope For Your Reply.
Thanks 
Zhi Chang


-- Original --
From:  "Miguel Lavalle";
Date:  Wed, Oct 14, 2015 11:22 AM
To:  "OpenStack Development Mailing List (not for usage 
questions)"; 

Subject:  Re: [openstack-dev] [Neutron][dns]What the meaning of"dns_assignment" 
and "dns_name"?

 
Zhi Chang,


Thank you for your questions. We are in the process of integrating Neutron and 
Nova with an external DNS service, using Designate as the reference 
implementation. This integration is being achieved in 3 steps. What you are 
seeing is the result of only the first one. These steps are:


1) Internal DNS integration in Neutron, which merged recently: 
https://review.openstack.org/#/c/200952/. As you may know, Neutron has an 
internal DHCP / DNS service based on dnsmasq for each virtual network that you 
create. Previously, whenever you created a port on a given network, your port 
would get a default host name in dnsmasq of the form 
'host-xx-xx-xx-xx.openstacklocal.", where xx-xx-xx-xx came from the port's 
fixed ip address "xx.xx.xx.xx" and "openstacklocal" is the default domain used 
by Neutron. This name was generated by the dhcp agent. In the above mentioned 
patchset, we are moving the generation of these dns names to the Neutron 
server, with the intent of allowing the user to specify it. In order to do 
that, you need to enable it by defining in neutron.conf the 'dns_domain' 
parameter with a value different to the default 'openstacklocal'. Once you do 
that, you can create or update a port and assign a value to its 'dns_name' 
attribute. Why is this useful? Please read on.

2) External DNS integration in Neutron. The patchset is being worked now: 
https://review.openstack.org/#/c/212213/. The functionality implemented here 
allows Neutron to publish the dns_name associated with a floating ip under a 
domain in an external dns service. We are using Designate as the reference 
implementation, but the idea is that in the future other DNS services can be 
integrated.. Where does the dns name and domain of the floating ip come from? 
It can come from 2 sources. Source number 1 is the floating ip itself, because 
in this patchset we are adding a dns_name and a dns_domain attributes to it. If 
the floating ip doesn't have a dns name and domain associated with it, then 
they can come from source number 2: the port that the floating ip is associated 
with (as explained in point 1, ports now can have a dns_name attribute) and the 
port's network, since this patchset adds dns_domain to networks.


3) Integration of Nova with Neutron's DNS. I have started the implementation of 
this and over the next few days will push the code to Gerrit for first review. 
When an instance is created, nova will request to Neutron the creation of the 
corresponding port specifying the instance's hostname in the port's 'dns_name' 
attribute (as explained in point 1). If the network where that port lives has a 
dns_domain associated with it (as explained in point 2) and you assign a 
floating ip to the port, your instance's hostname will be published in the 
external dns service.


To make it clearer, here I walk you through an example that I executed in my 
devstack: http://paste.openstack.org/show/476210/


As mentioned above, we also allow the dns_name and dns_domain to be published 
in the external dns to be defined at the floating ip level. The reason for this 
is that we envision a use case where the name and ip address made public in the 
dns service are stable, regardless of the nova instance associated with the 
floating ip.


If you are attending the upcoming Tokyo summit, you could attend the following 
talk for further information:  
http://openstacksummitoctober2015tokyo.sched.org/event/5cbdd5fb4a6d080f93a5f321ff59009c#.Vh3KMZflRz2
 Looking forward to see you there!

Re: [openstack-dev] [Neutron][dns]What the meaning of"dns_assignment" and "dns_name"?

[Miguel Lavalle]

Zhi Chang,

You got all the steps correct. A few clarifications:


   1. Address 104.130.78.191 is the ip address of my devstack VM. When you
   deploy Designate in devstack, it starts an instance of PowerDNS for you.
   Designate then pushes all its zones and records to that PowerDNS instance.
   When I say "dig my-instance.my-example.org @104.130.78.191" I am
   instructing dig to direct the lookup to the DNS server @ 104.130.78.191:
   in other words, my PowerDNS instance
   2. For you to be able to execute the same steps in your devstack, you
   need:
  - The code in patchset https://review.openstack.org/#/c/212213/
  - The modified nova code in nova/network/neutronv2/api.py that I
  haven't pushed to Gerrit yet
  - Configure a few parameters in /etc/neutron/neutron.conf
  - Migrate the Neutron database, because I added columns to a couple
  of tables

Let me know if you want to try this in your devstack. If the answer is yes,
I will let you know when I push the nova change to gerrit. At that point, I
will provide detailed steps to accomplish point 2 above

Best regards


Miguel


On Wed, Oct 14, 2015 at 12:53 AM, Zhi Chang 
wrote:

> Hi, Miguel
> Thank you so much for your reply. You are so patient!
> After reading your reply, I still have some questions to ask you. :-)
> Below, is my opinion about the http://paste.openstack.org/show/476210/,
> please read it and tell me whether I was right.
> (1). Define a DNS domain
> (2). Update a network's "dns_domain" attribute to the DNS domain which
> defined in the step1
> (3). Create a VM in this network. The instance's port will assign
> instance's hostname to it's dns_name attribute
> (4). Create a floating IP for this VM
> (5). In Designate, there will be generate a new A record. This record
> is a link between floating IP and dns_name+domain_name. Just like your
> record: deec921d-b630-4479-8932-c5ec7c530820 | A |
> my-instance.my-example.org. | 172.24.4.3
>   (6). I am don't understand where the IP address "104.130.78.191" comes
> from. I think this address is a public DNS, just like 8.8.8.8. Does it
> right?
>(7). I can dig "my-instance.my-example.org." by a public DNS. And the
> result is the floating IP.
>
> Does my understanding was right?
>
> Hope For Your Reply.
> Thanks
> Zhi Chang
>
> -- Original --
> *From: * "Miguel Lavalle";
> *Date: * Wed, Oct 14, 2015 11:22 AM
> *To: * "OpenStack Development Mailing List (not for usage questions)"<
> openstack-dev@lists.openstack.org>;
> *Subject: * Re: [openstack-dev] [Neutron][dns]What the meaning
> of"dns_assignment" and "dns_name"?
>
> Zhi Chang,
>
> Thank you for your questions. We are in the process of integrating Neutron
> and Nova with an external DNS service, using Designate as the reference
> implementation. This integration is being achieved in 3 steps. What you are
> seeing is the result of only the first one. These steps are:
>
> 1) Internal DNS integration in Neutron, which merged recently:
> https://review.openstack.org/#/c/200952/. As you may know, Neutron has an
> internal DHCP / DNS service based on dnsmasq for each virtual network that
> you create. Previously, whenever you created a port on a given network,
> your port would get a default host name in dnsmasq of the form
> 'host-xx-xx-xx-xx.openstacklocal.", where xx-xx-xx-xx came from the port's
> fixed ip address "xx.xx.xx.xx" and "openstacklocal" is the default domain
> used by Neutron. This name was generated by the dhcp agent. In the above
> mentioned patchset, we are moving the generation of these dns names to the
> Neutron server, with the intent of allowing the user to specify it. In
> order to do that, you need to enable it by defining in neutron.conf the
> 'dns_domain' parameter with a value different to the default
> 'openstacklocal'. Once you do that, you can create or update a port and
> assign a value to its 'dns_name' attribute. Why is this useful? Please read
> on.
>
> 2) External DNS integration in Neutron. The patchset is being worked now:
> https://review.openstack.org/#/c/212213/. The functionality implemented
> here allows Neutron to publish the dns_name associated with a floating ip
> under a domain in an external dns service. We are using Designate as the
> reference implementation, but the idea is that in the future other DNS
> services can be integrated.. Where does the dns name and domain of the
> floating ip come from? It can come from 2 sources. Source number 1 is the
> floating ip itself, because in this patchset we are adding a dns_name and a
> dns_domain attributes to it. If the floating ip doesn't have a dns name and
> domain associated with it, then they can come from source number 2: the
> port that the floating ip is associated with (as explained in point 1,
> ports now can have a dns_name attribute) and the port's network, since this
> patchset adds dns_domain to 

Re: [openstack-dev] [Neutron][dns]What the meaning of "dns_assignment" and "dns_name"?

[Miguel Lavalle]

Zhi Chang,

Thank you for your questions. We are in the process of integrating Neutron
and Nova with an external DNS service, using Designate as the reference
implementation. This integration is being achieved in 3 steps. What you are
seeing is the result of only the first one. These steps are:

1) Internal DNS integration in Neutron, which merged recently:
https://review.openstack.org/#/c/200952/. As you may know, Neutron has an
internal DHCP / DNS service based on dnsmasq for each virtual network that
you create. Previously, whenever you created a port on a given network,
your port would get a default host name in dnsmasq of the form
'host-xx-xx-xx-xx.openstacklocal.", where xx-xx-xx-xx came from the port's
fixed ip address "xx.xx.xx.xx" and "openstacklocal" is the default domain
used by Neutron. This name was generated by the dhcp agent. In the above
mentioned patchset, we are moving the generation of these dns names to the
Neutron server, with the intent of allowing the user to specify it. In
order to do that, you need to enable it by defining in neutron.conf the
'dns_domain' parameter with a value different to the default
'openstacklocal'. Once you do that, you can create or update a port and
assign a value to its 'dns_name' attribute. Why is this useful? Please read
on.

2) External DNS integration in Neutron. The patchset is being worked now:
https://review.openstack.org/#/c/212213/. The functionality implemented
here allows Neutron to publish the dns_name associated with a floating ip
under a domain in an external dns service. We are using Designate as the
reference implementation, but the idea is that in the future other DNS
services can be integrated.. Where does the dns name and domain of the
floating ip come from? It can come from 2 sources. Source number 1 is the
floating ip itself, because in this patchset we are adding a dns_name and a
dns_domain attributes to it. If the floating ip doesn't have a dns name and
domain associated with it, then they can come from source number 2: the
port that the floating ip is associated with (as explained in point 1,
ports now can have a dns_name attribute) and the port's network, since this
patchset adds dns_domain to networks.

3) Integration of Nova with Neutron's DNS. I have started the
implementation of this and over the next few days will push the code to
Gerrit for first review. When an instance is created, nova will request to
Neutron the creation of the corresponding port specifying the instance's
hostname in the port's 'dns_name' attribute (as explained in point 1). If
the network where that port lives has a dns_domain associated with it (as
explained in point 2) and you assign a floating ip to the port, your
instance's hostname will be published in the external dns service.

To make it clearer, here I walk you through an example that I executed in
my devstack: http://paste.openstack.org/show/476210/

As mentioned above, we also allow the dns_name and dns_domain to be
published in the external dns to be defined at the floating ip level. The
reason for this is that we envision a use case where the name and ip
address made public in the dns service are stable, regardless of the nova
instance associated with the floating ip.

If you are attending the upcoming Tokyo summit, you could attend the
following talk for further information:
http://openstacksummitoctober2015tokyo.sched.org/event/5cbdd5fb4a6d080f93a5f321ff59009c#.Vh3KMZflRz2
Looking forward to see you there!

Hope this answers your questions

Best regards

Miguel Lavalle

On Tue, Oct 13, 2015 at 9:58 AM, Zhi Chang  wrote:

> Hi, all
> I install the latest devstack and create a vm by nova. I get the
> port's info which created by Neutron. I'm confused that what the meaning of
> column "dns_assignment" and column "dns_name".
> First, column "dns_assignment" is a read-only attribute. What is it
> used for? I think that this column is useless except shows DNS infomation
> (include hostname, ip, fqdn). Does my thought right?
> Second, I don't quite understand what the meaning of column
> "dns_name". I can update this column, but there is nothing happen when my 
> operation
> was done. In other words, this column has no change when I run "neutron
> port-update xxx --dns_name=test". What the column "dns_name" use for?
>
>
>
> Thanks
> Zhi Chang
>
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[openstack-dev] [Neutron][dns]What the meaning of "dns_assignment" and "dns_name"?

[Zhi Chang]

Hi, all
I install the latest devstack and create a vm by nova. I get the port's 
info which created by Neutron. I'm confused that what the meaning of column 
"dns_assignment" and column "dns_name".
First, column "dns_assignment" is a read-only attribute. What is it used 
for? I think that this column is useless except shows DNS infomation (include 
hostname, ip, fqdn). Does my thought right?
Second, I don't quite understand what the meaning of column "dns_name". I 
can update this column, but there is nothing happen when my operation was done. 
In other words, this column has no change when I run "neutron port-update xxx 
--dns_name=test". What the column "dns_name" use for?






Thanks
Zhi Chang__
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