dibbler tool for dhcpv6 is concluded

[zhaobo]

Hi team,
according to the latest annoucement of https://github.com/tomaszmrugalski/dibbler,
seems the said project is concluded by lacking maintainers,
and I also found the said tools have been as the Ipv6 dhcp default implementation.

The author suggest https://gitlab.isc.org/isc-projects/kea . Is there any plan for this in Neutron team?

Thanks very much

[Oleg Bondarev (obondarev)]

It's not an actual bug in Neutron, but the topic is worth a discussion.

[zhaobo (zhaobo6)]

Yeah, it's not a bug for Neutron, but the following resposibility of that tools need to be clear, that's the reason I raise here, and want to know how Neutron team treat it. Abandon? Self-maintaining? Or Choose an new one?

Thanks.

[Slawek Kaplonski (slaweq)]

Hi,

I don't know about any plans in Neutron to work on another driver for PD. But feel free to propose patch with some. If You have some plan to do that, You can IMO propose some short description of what software do You want to use and how You want to implement such driver. We can than discuss that in the drivers meeting as any other RFE.

[zhaobo (zhaobo6)]

Thanks, Slawek Kaplonski. We are considering how to process it. I have no idea now, if Neutron team has any idea, I think that would be great.. Thanks very much

[Slawek Kaplonski (slaweq)]

Hi Zhaobo,

For dibbler there is PD driver class in https://github.com/openstack/neutron/blob/1ad9ca56b07ffdc9f7e0bc6a62af61961b9128eb/neutron/agent/linux/dibbler.py#L71
IMO, You can propose similar driver for some other tool so it can be choose by operator.

[Slawek Kaplonski (slaweq)]

Hi Zhaobo,

Can You maybe describe us here possible solutions, what are dibbler alternatives and which we should consider as next "in-tree" driver?

[Lajos Katona (lajos-katona)]

It was topic on last l3-team meeting:
http://eavesdrop.openstack.org/irclogs/%23openstack-meeting/%23openstack-meeting.2021-05-19.log.html#t2021-05-19T14:38:02

We checked the proposed alternative Kea, and the questions which come out:
* License: Kea is MPL2.0 liensed, which need to be checked.
* Instead of Kea use ovs native implementation if possible, of course that is not good for linuxbridge or for sriov.

[Lajos Katona (lajos-katona)]

I checked a little this topic:
Dibbler: see [1] or [2]:
The feature "external scripts" is used to catch env variables (PREFIX1) set by dibbler server, and write it to files from where l3 agent reads and act.

In Kea there's a similar feature called Hooks (see [3] ) which has an external "script run" support hook (see [4])
This feature is available from Kea 1.9.5, but i.e. on Ubuntu 20.04 I see 1.6.2 (see [5] )

More investigation is necessary if it is possible to run only this part of Kea to have the external script hook.

[1] https://klub.com.pl/dhcpv6/doc/dibbler-user.pdf
[2] https://github.com/tomaszmrugalski/dibbler/blob/master/doc/dibbler-user-features.tex#L986
[3] https://kea.readthedocs.io/en/latest/arm/hooks.html
[4] https://kea.readthedocs.io/en/latest/arm/hooks.html#run-script-support
[5] https://packages.ubuntu.com/search?suite=focal&keywords=kea

[Slawek Kaplonski (slaweq)]

Lets discuss that RFE on the next drivers meeting which will be on Friday 10.09.2021

[Slawek Kaplonski (slaweq)]

We discussed that RFE on the drivers meeting https://meetings.opendev.org/meetings/neutron_drivers/2021/neutron_drivers.2021-09-10-14.05.log.html#l-96
We all agreed there that we need new driver for some PD backend in Neutron so we approved that RFE. Now we need to choose wisely for what backend we want to write new driver. If You are interested in working on this thing, please propose some backends with pros and cons for them and we then can discuss which one to choose.

[Lajos Katona (lajos-katona)]

Asked around for the licensing question, see this thread:
http://lists.openstack.org/pipermail/openstack-discuss/2021-September/024876.html

Summary: Neutron can include MPL2.0 licensed things.

[Lajos Katona (lajos-katona)]

After some playing with ISC/Kea I wrote an issue for them because can't make it work and delegate prefixes for me:
https://gitlab.isc.org/isc-projects/kea/-/issues/2140

[Lajos Katona (lajos-katona)]

Based on PTG comment perhaps worth to check dhcpcd (http://roy.marples.name/projects/dhcpcd/).
It has hooks support: https://www.daemon-systems.org/man/dhcpcd-run-hooks.8.html

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/836863

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/836863
Committed: https://opendev.org/openstack/neutron/commit/35b8c8d56d175c27a9ecd05351b1ff390dac2a91
Submitter: "Zuul (22348)"
Branch: master

commit 35b8c8d56d175c27a9ecd05351b1ff390dac2a91
Author: elajkat <email address hidden>
Date: Tue Apr 5 19:27:48 2022 +0200

    Doc: Add warning for not supported Prefix Delegation

    Based on discussions during the Zed PTG (see [1]) mark Prefix Delegation
    as experimental.
    Add warning to cfg option ipv6_pd_enabled and to IPv6 documentation's
    PD section that the feature has low test coverage, and dibbler is
    concluded (the tool used for notifing Neutron that a prefix was changed)
    see: [2].

    [1]: https://etherpad.opendev.org/p/neutron-zed-ptg#L208
    [2]: https://github.com/tomaszmrugalski/dibbler#project-status

    Related-Bug: #1916428
    Change-Id: Ia712eb6f5b6f947aeab89ba7c018771eb4104e37

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/879030

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/879030
Committed: https://opendev.org/openstack/neutron/commit/3e65ef863cc4913fd6414e4010ec2506632c00b9
Submitter: "Zuul (22348)"
Branch: master

commit 3e65ef863cc4913fd6414e4010ec2506632c00b9
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Wed Mar 29 20:41:33 2023 +0200

    Mark "ipv6_pd_enabled" as deprecated and experimental.

    This functionality will be kept in the code as experimental as long
    as no bugs are reported againts this feature.

    This patch also marks the config option "ipv6_pd_enabled" as
    experimental. In order to enable this flag, it is needed to configure
    the "experimental.ipv6_pd_enabled" flag too.

    Related-Bug: #1916428
    Change-Id: I27aeed74f308d5bdf0210e76d9557f95b66c71bf