Openstack neutron linuxbridge help

Hi All

I’ve been trying to build a neutron-api subordinate for setting up Linuxbridge-agent
I’ve been following the example guide for openstack ussuri

my repo: which I’m using the reactive setup.

I’m wanting have this charm install different packages and start services based on the parent charm.

for example:
install package1, package2 and package3
start service1, service2 and service3
but if
install package1
start service1

It’s mainly just how to write the how to figure out which parent is linked?
once I know I can do this I can finish off the config files and the rest of the config options.

any help would be great.

@openstack-charmers would you mind giving some pointers maybe?

Hello Graeme,

Welcome to the Juju community and thank you for your interest in the OpenStack charms.

First off I would like to ask you if you have a specific use case behind the wish for writing a charm for the Neutron linuxbridge driver? It is getting quite vintage and I’m not sure about the state of support for it in the upstream Neutron code base.

I see you have found the linuxbridge driver referenced in the upstream install Neutron on Ubuntu docs and all I can say is that unfortunately they look a bit dated. If you want updated documentation on installation of OpenStack with the charms you can take a look at the OpenStack Charms Deployment Guide.

On to your charming question:
For how to detect which principle charm your subordinate charm is related to I would use different endpoints/interfaces. That will allow your subordinate charm to know for sure what is in the other end. Both the neutron-api and the nova-compute provide subordinate relations and use different interfaces that you can consume from your subordinate charm.

As for the duality you propose in your charm I would not recommend that approach.

The purpose of the subordinate charm you deploy with neutron-api is very different from the purpose of the subordinate charm you deploy along with nova-compute.

Hi Frode

Thank you so much for the response.

The reason I have been looking at the linuxbridge been simply down to vlan-transparency as OVS and OVN do not support vlan-transparency. Linuxbridge is the only supported driver.

Some background:
I’ve been tasked to create an openstack lab for the openstack lab will host network switches and routers and requires vlans to be transparent from the provider side.

I totally understand that in general not may people/companies would require this, but until OVN supports vlan-transparency I’m stuck with trying to get openstack to use linuxbridge driver.

On the charm I was hoping to use one charm to rule them all but what you have said is starting to make more sense. I’ll look at two separate charms and use a relation between them to share settings to make sure nova-compute is not effected with neutron-api-subordinate.

I was looking at the principal_unit in the charmhelpers and them placing this in the charms_openstack.charm.OpenStackCharm to add if the principal is contains neutron.
again looking at what you saying it would cause problems.

parent = principal_unit().split('/')[0]
if 'neutron' in parent:
    extra_pkgs = ['neutron-plugin-ml2',
    extra_serv = [

thanks again for the reply I have some thinking to do and will have to create another charm.

Just an update if any does look at this. Ussuri has marked linux bridge as deprecated not great as I remember 2019 STG summary stated linux bridge is not going any where.

A brighter side is that they are working on OVN to support vlan transparency which could help people move away from linux bridge.