[openstack-dev] [neutron] [IPv6] [ironic] New API format for extra_dhcp_opts

Carlino, Chuck chuck.carlino at hp.com
Thu Oct 2 02:53:46 UTC 2014


As a 'heads up', adding ironic to the thread since they are a 'key' consumer of this api.


On Oct 1, 2014, at 3:15 AM, Xu Han Peng <pengxuhan at gmail.com<mailto:pengxuhan at gmail.com>> wrote:

ip_version sounds great.

Currently the opt-names are written into the configuration file of dnsmasq directly. So I would say yes, they are coming from dnsmasq definitions.

It will make more sense when ip_version is missing or null, the option apply to both since we could have only ipv6 or ipv4 address on the port. However, the validation of opt-value should rule out the ones which are not suitable for the current address. For example, an IPv6 dns server should not be specified for IPv4 address port, etc...

Xu Han

On 09/30/2014 08:41 PM, Robert Li (baoli) wrote:
Xu Han,

That looks good to me. To keep it consistent with existing CLI, we should use ip-version instead of ‘version’. It seems to be identical to prefixing the option_name with v4 or v6, though.

Just to clarify, are the available opt-names coming from dnsmasq definitions?

With regard to the default, your suggestion "version is optional (no version means version=4)." seems to be different from Mark’s:
I’m -1 for both options because neither is properly backwards compatible.  Instead we should add an optional 3rd value to the dictionary: “version”.  The version key would be used to make the option only apply to either version 4 or 6.  If the key is missing or null, then the option would apply to both.

Thanks,
Robert

On 9/30/14, 1:46 AM, "Xu Han Peng" <pengxuhan at gmail.com<mailto:pengxuhan at gmail.com>> wrote:

Robert,

I think the CLI will look something like based on Mark's suggestion:

neutron port-create extra_dhcp_opts opt_name=<dhcp_option_name>,opt_value=<value>,version=4(or 6) <network>

This extra_dhcp_opts can be repeated and version is optional (no version means version=4).

Xu Han

On 09/29/2014 08:51 PM, Robert Li (baoli) wrote:
Hi Xu Han,

My question is how the CLI user interface would look like to distinguish between v4 and v6 dhcp options?

Thanks,
Robert

On 9/28/14, 10:29 PM, "Xu Han Peng" <pengxuhan at gmail.com<mailto:pengxuhan at gmail.com>> wrote:

Mark's suggestion works for me as well. If no one objects, I am going to start the implementation.

Thanks,
Xu Han

On 09/27/2014 01:05 AM, Mark McClain wrote:

On Sep 26, 2014, at 2:39 AM, Xu Han Peng <pengxuhan at gmail.com<mailto:pengxuhan at gmail.com>> wrote:

Currently the extra_dhcp_opts has the following API interface on a port:

{
    "port":
    {
        "extra_dhcp_opts": [
            {"opt_value": "testfile.1","opt_name": "bootfile-name"},
            {"opt_value": "123.123.123.123", "opt_name": "tftp-server"},
            {"opt_value": "123.123.123.45", "opt_name": "server-ip-address"}
        ],
        ....
     }
}

During the development of DHCPv6 function for IPv6 subnets, we found this format doesn't work anymore because an port can have both IPv4 and IPv6 address. So we need to find a new way to specify extra_dhcp_opts for DHCPv4 and DHCPv6, respectively. ( https://bugs.launchpad.net/neutron/+bug/1356383)

Here are some thoughts about the new format:

Option1: Change the opt_name in extra_dhcp_opts to add a prefix (v4 or v6) so we can distinguish opts for v4 or v6 by parsing the opt_name. For backward compatibility, no prefix means IPv4 dhcp opt.

        "extra_dhcp_opts": [
            {"opt_value": "testfile.1","opt_name": "bootfile-name"},
            {"opt_value": "123.123.123.123", "opt_name": "v4:tftp-server"},
            {"opt_value": "[2001:0200:feed:7ac0::1]", "opt_name": "v6:dns-server"}
        ]

Option2: break extra_dhcp_opts into IPv4 opts and IPv6 opts. For backward compatibility, both old format and new format are acceptable, but old format means IPv4 dhcp opts.

        "extra_dhcp_opts": {
             "ipv4": [
                    {"opt_value": "testfile.1","opt_name": "bootfile-name"},
                    {"opt_value": "123.123.123.123", "opt_name": "tftp-server"},
             ],
             "ipv6": [
                    {"opt_value": "[2001:0200:feed:7ac0::1]", "opt_name": "dns-server"}
             ]
        }

The pro of Option1 is there is no need to change API structure but only need to add validation and parsing to opt_name. The con of Option1 is that user need to input prefix for every opt_name which can be error prone. The pro of Option2 is that it's clearer than Option1. The con is that we need to check two formats for backward compatibility.

We discussed this in IPv6 sub-team meeting and we think Option2 is preferred. Can I also get community's feedback on which one is preferred or any other comments?


I’m -1 for both options because neither is properly backwards compatible.  Instead we should add an optional 3rd value to the dictionary: “version”.  The version key would be used to make the option only apply to either version 4 or 6.  If the key is missing or null, then the option would apply to both.

mark




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