devstack installation fails for neutron- ovn_agent on master branch

[Vishal Manchanda]

./stack/sh scripts fails at line [1] with error msg ``Error: any valid prefix is expected rather than "/27"``.
My local.conf file can be found here http://paste.openstack.org/show/805864/ .
I think devstack failing due to some recent patches merged related to ovn into master branch.

[1] https://github.com/openstack/devstack/blob/master/lib/neutron_plugins/ovn_agent#L286

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Hello:

If you are using OVN and you defined a FLOATING_RANGE, then you need to set PUBLIC_NETWORK_GATEWAY [1].
"""
The PUBLIC_NETWORK_GATEWAY is the gateway that server would normally use to get off the network. Q_FLOATING_ALLOCATION_POOL controls the range of floating ips that will be handed out. As we are sharing your existing network, you'll want to give it a slice that your local dhcp server is not allocating. Otherwise you could easily have conflicting ip addresses, and cause havoc with your local network.
"""

Regards.

[1]https://github.com/openstack/devstack/blob/master/doc/source/networking.rst#shared-guest-interface

[Vishal Manchanda (vishalmanchanda)]

@Rodolfo, hi thanks for the quick response, what if I didn't define a FLOATING_RANGE in my local.conf then in that case still I have to set PUBLIC_NETWORK_GATEWAY in local.conf file?

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Yes, you need to define PUBLIC_NETWORK_GATEWAY, in the same CIDR as FLOATING_RANGE.

I need to check with Lucas Gomes if [1] should create a subnet in the external network, with range FLOATING_RANGE, same as in "_neutron_create_public_subnet_v4". Then, retrieve the subnet info, including the gateway, that could be used if PUBLIC_NETWORK_GATEWAY is not defined.

[1]https://github.com/openstack/devstack/blob/22038a9a8c4418d6d49bed83024a3cd97e627860/lib/neutron_plugins/ovn_agent#L276-L304

[Akihiro Motoki (amotoki)]

This issue happens if a user just follows DevStack quick start https://docs.openstack.org/devstack/latest/#create-a-local-conf . It happens as a result of switching the network defualt backend to OVN. We need to consider this bug as the gap in OVN migration.

As another workaround, if you do not care a network backend used, you can use OVS as backend as a workaround. If so, you can check the details in http://lists.openstack.org/pipermail/openstack-discuss/2021-May/022410.html.

[Vishal Manchanda (vishalmanchanda)]

I see because if I didn't add any FLOATING_RANGE in my local.conf http://paste.openstack.org/show/806211/
I still get a similar error on the master branch ``Error: any valid prefix is expected rather than "/24".

[Akihiro Motoki (amotoki)]

Vishal, I guess you just use local.conf similar to https://docs.openstack.org/devstack/latest/#create-a-local-conf (i.e., local.conf without any specific network related configurations), right?

[Akihiro Motoki (amotoki)]

Okay, you pasted your local.conf during I wrote a comment.

[Akihiro Motoki (amotoki)]

I changed the status to "Confirmed" as I confirmed this happens with the sample local.conf in the "Quick Start" page.

[Lucas Alvares Gomes (lucasagomes)]

Hi,

I believe this problem is cause by this patch https://review.opendev.org/c/openstack/devstack/+/793397/, previously this OVN_L3_CREATE_PUBLIC_NETWORK was set to False and the create_public_bridge method wasn't been called when running devstack locally. However we needed to change the default to True in order to fix some problems with the nodepool jobs from infra because they do not rely on customized zuul configurations (only defaults) to run their jobs now that OVN is the default in DevStack.

I will look into this problem, but, as a workaround for this problem please set the following variable in your local.conf:

OVN_L3_CREATE_PUBLIC_NETWORK=False

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/devstack/+/793962

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/devstack/+/793997

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Pavlo Shchelokovskyy <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/devstack/+/793997

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/devstack/+/795371

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Rodolfo Alonso <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/devstack/+/793962
Reason: Superseded by https://review.opendev.org/c/openstack/devstack/+/795371

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/devstack/+/795371
Committed: https://opendev.org/openstack/devstack/commit/95298788085de38342e789bf10c35849c7117dfc
Submitter: "Zuul (22348)"
Branch: master

commit 95298788085de38342e789bf10c35849c7117dfc
Author: Radosław Piliszek <email address hidden>
Date: Tue Jun 8 16:19:40 2021 +0000

    [OVN] Set up routing on public bridge like OVS did

    This fixes various reported and unreported issues with the new
    behaviour.

    Removes code repetition as well to pay off some technical debt.

    Closes-Bug: #1930360
    Change-Id: I726c532e96ca434520838ae8a35d5b88b6dd337b

[bilelsalem (bilelsalem)]

Hello! I have the same error ! how can I resolve it please?

[Radosław Piliszek (yoctozepto)]

Checkout the current master branch contents. It's fixed.