openstack/neutron-specs
Code Issues Proposed changes
e1343b6f4c
neutron-specs/specs/kilo/extra-dhcp-opts-ipv4-ipv6.rst
Xu Han Peng 87a641dc9b Add Spec for Extra DHCP Options for IPv4 and IPv6 
BP extra-dhcp-opts-ipv4-ipv6

DocImpact
APIImpact

Change-Id: I114f6bd63a6cb3edb589f16b3f2e65105c4a1f5e
2014-12-10 10:18:14 +08:00

5.8 KiB
Raw Blame History

Extra DHCP Options for IPv4 and IPv6

Include the URL of your launchpad blueprint:

https://blueprints.launchpad.net/neutron/+spec/extra-dhcp-opts-ipv4-ipv6.rst

Problem Description

A detailed description of the problem:

  • Currently extra_dhcp_opts only works for DHCPv4 or DHCPv6 address on a port. Since a port can have both IPv4 and IPv6 address, we need to find a new way to specify extra dhcp options for DHCPv4 and DHCPv6, respectively.
  • There is no validation of DHCP options, therefore any option name and value can be specified for a port.

Proposed Change

  • A new attribute "ip_version" will be used in Neutron port create/update extra_dhcp_opts API to specify the IP version of a given DHCP option.

  • "ip_version" will be used to differentiate the option for DHCPv4 or DHCPv6 when processing the DHCP options for a given port.

  • How to deal with the case that ip_version is not specified: ip_version is default to 4 if ip_version is not specified for backward compatibility.

  • Validation of DHCP option in DNSMASQ implementation: We can get a list of supported dhcp option names in DNSMASQ by: "dnsmasq --help dhcp" and "dnsmasq --help dhcp6".

    Unknown DHCP option names and wrong ip_version of a option (for example, IPv6 dns server with ip_version=4) should not be applied with clear error messages.

  • Ignoring the options which cannot be applied If an option cannot be applied to a port due to the conflict between port's address and ip_version of the option, the option will be ignored until the port is updated with new addresses.

Data Model Impact

  • A new column "ip_version" will be added to Neutron extradhcpopts table with Integer type and nullable=True.

  • Upgrade database migration requires adding this new column and downgrade database migration requires dropping this new column.

  • The defult value of this column if not specified and the value after upgrade is null.

    +-----------+--------------+------+-----+---------+-------+
| Field     | Type         | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| id        | varchar(36)  | NO   | PRI | NULL    |       |
| port_id   | varchar(36)  | NO   | MUL | NULL    |       |
| opt_name  | varchar(64)  | NO   |     | NULL    |       |
| opt_value | varchar(255) | NO   |     | NULL    |       |
| ip_version| int(11)      | YES  |     | NULL    |       |
+-----------+--------------+------+-----+---------+-------+

REST API Impact

The modified extra_dhcp_opts attribute map is described as follows:

::

POST /v2.0/ports Accept: application/json

"port":{

... "extra_dhcp_opts": [ {"opt_value": "pxelinux.0", "opt_name": "bootfile-name", "ip_version": 4}, {"opt_value": "123.123.123.123", "opt_name": "tftp-server", "ip_version": 4}, {"opt_value": "123.123.123.45", "opt_name": "server-ip-address", "ip_version": 4} ], ...}

The added attribute "ip_version" is not required. The allowed value of "ip_version" is 4 or 6.

Security Impact

None

Notifications Impact

None

Other End User Impact

Neutron client change: neutron port-create and neutron port-update needs following changes:

::
neutron port-create Network

--extra-dhcp-opt opt_name=<dhcp_option_name>,opt_value=<value>,ip_version={4,6}

neutron port-update Network

--extra-dhcp-opt opt_name=<dhcp_option_name>,opt_value=<value>,ip_version={4,6}

Performance Impact

None

IPv6 Impact

This change is particularly designed for IPv6 tenant subnet ports.

Other Deployer Impact

During data migration, ip_version will be set to 4 to keep backward compability. The unsupported options will be ignored by DNSMASQ implementation.

Developer Impact

None

Community Impact

This proposed change has been discussed in Neutron IPv6 sub-team meeting and community development mail list:

http://lists.openstack.org/pipermail/openstack-dev/2014-September/047222.html

Alternatives

None

Implementation

Assignee(s)

Primary assignee:

xuhanp

Other contributors:

TBD

Work Items

  • Add new API attribute and change current linux dhcp implementation by dnsmasq to treat IPv4 and IPv6 dhcp option separately.
  • DB migration script to add "ip_version" column in Neutron extradhcpopts table.
  • Add validation of extra dhcp options.
  • Add "ip_version" attribute to Neutron client port create and port update CLI.

Dependencies

None

Testing

Tempest Tests

Add tempest API test for Neutron port creation and update using the new "ip_version" attribute of extra_dhcp_opts.

Functional Tests

Functional tests towards DHCPv4 and DHCPv6 option name, value and the ip version.

API Tests

API test to the added "ip_version" attribute of Port extra_dhcp_opts.

Documentation Impact

Neutron API documation should be modified to add the new attribute.

User Documentation

The allowed DHCP option name and values should be documented in User Documentation. Examples for frequently used options should be provided.

Developer Documentation

Developer API documentation should be updated with the new attribute.

References