neutron-specs/specs/zed/custom-floatingip-distributed.rst

Floating IP distributed

Launchpad Bug: https://bugs.launchpad.net/neutron/+bug/1978039

Neutron adds distributed attributes to each Floating IP. Users can set this attribute according to their actual environment and use requirements.

Problem Description

Neutron supports setting the floating IP to distributed. External traffic can go directly to the compute node without passing through the network node, and increases the network performance. This is very useful for the demand for high-performance networks.

However, we can decide whether floating ips are distributed or centralized by setting configuration option(ovn backend) or setting router's "distributed" attribute(ovs dvr mode). This is global. After configuration, all floating ips are centralized or distributed.

The actual use may be complicated:

• Not all vms with floating ip may require high-performance networks, and may only be exposed to the outside world to provide services.
• Due to equipment conditions, some compute nodes are not equipped with external network card. If enable distributed, the vm of this compute node cannot allocate floating ip.

Proposed Change

Add new API extension to extend floatingip resource in Neutron with distributed attribute. If not set this attribute, the distributed attribute of the router will be used for the floating ip¹.

Server side changes

A new API extension of Neutron will be added with new attribute for the floatingip resource. This new attribute will be called distributed:

RESOURCE_ATTRIBUTE_MAP = {
    l3.FLOATINGIPS: {
        "distributed": {
            'allow_post': True,
            'allow_put': True,
            'convert_to': converters.convert_to_boolean_if_not_none,
            'default': constants.ATTR_NOT_SPECIFIED,
            'is_visible': True,
            'is_filter': True
        }
    }
}

DB Impact

Extend the floatingips table with boolean column distributed.

REST API Impact

New API extension: floatingip-distributed introducing new floatingip attribute: distributed.

Client Impact

Relevant changes in OSC and openstacksdk to add support for new floatingip's attribute. To enable it for floatingip, it should be something like:

openstack floating ip create --distributed

and to disable it:

openstack floating ip create --centralized

and update it:

openstack floating ip update [--distributed | --centralized ]

Testing

• Unit tests.
• Functional test.
• Tempest tests in neutron-tempest-plugin.

Assignee(s)

• ZhouHeng <zhouhenglc@inspur.com>

References

---

1. Neutron Drivers meeting, June 24, 2022 https://meetings.opendev.org/meetings/neutron_drivers/2022/neutron_drivers.2022-06-24-14.00.log.html#l-116↩︎