DHCP entries for floating IP ports are not needed really

[Slawek Kaplonski]

When Floating IP is created, there is unbound port created for it too. And if subnet on which is this port has enabled DHCP, then this port has entry in the dnsmasq leases file as any other port. But this isn't really needed in such case.
Similary, there is no need to configure by DHCP agent ports which belongs to the routers. In some cases it may decrease load of the agents a bit.

[Slawek Kaplonski (slaweq)]

Patch https://review.opendev.org/c/openstack/neutron/+/772492

[LIU Yulong (dragon889)]

Maybe we should disable the DHCP for the network (external network, HA network and so on) at the begining. Yes, it is the bug:
https://bugs.launchpad.net/neutron/+bug/1911864

[Oleg Bondarev (obondarev)]

I know cases when VMs are created on external network - disabling this ability will affect users.

Aren't HA network subnets created with dhcp disabled already?

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 17.1.1 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 18.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 15.3.4 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 16.3.2 release.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/777123
Committed: https://opendev.org/openstack/neutron/commit/2f662482489b62667759d05164013e2ef6b7da6d
Submitter: "Zuul (22348)"
Branch: stable/rocky

commit 2f662482489b62667759d05164013e2ef6b7da6d
Author: Slawek Kaplonski <email address hidden>
Date: Tue Jan 26 11:22:39 2021 +0100

    Don't configure dnsmasq entries for "network" ports

    Ports with device_owner like:
    * floating_ip,
    * DHCP,
    * some types of router ports, like: HA interface interface,
    don't need to be configured in the dnsmasq file.
    So there is no need to reload dnsmasq every time when such port is
    added/updated to the network.

    This patch adds skip in such case which should improve load on the
    Neutron DHCP agent.

    Conflicts:
        neutron/agent/linux/dhcp.py
        neutron/agent/dhcp/agent.py

    # Fix for Rocky gate (backports to other branches didn't really
    # that depends-on:
    Depends-On: https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/786657

    Closes-Bug: #1913269
    Change-Id: I63221507713b941c261cdf88781133149da8ab8d
    (cherry picked from commit e4bbeee2060058d079885339e99ef7e6e366de16)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron queens-eol release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron rocky-eol release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron stein-eol release.