[openstack-dev] [TripleO] easily identifying how services are configured

James Slagle james.slagle at gmail.com
Thu Jul 5 18:13:17 UTC 2018

On Thu, Jul 5, 2018 at 1:50 PM, Dan Prince <dprince at redhat.com> wrote:
> Last week I was tinkering with my docker configuration a bit and was a
> bit surprised that puppet/services/docker.yaml no longer used puppet to
> configure the docker daemon. It now uses Ansible [1] which is very cool
> but brings up the question of how should we clearly indicate to
> developers and users that we are using Ansible vs Puppet for
> configuration?
> TripleO has been around for a while now, has supported multiple
> configuration ans service types over the years: os-apply-config,
> puppet, containers, and now Ansible. In the past we've used rigid
> directory structures to identify which "service type" was used. More
> recently we mixed things up a bit more even by extending one service
> type from another ("docker" services all initially extended the
> "puppet" services to generate config files and provide an easy upgrade
> path).
> Similarly we now use Ansible all over the place for other things in
> many of or docker and puppet services for things like upgrades. That is
> all good too. I guess the thing I'm getting at here is just a way to
> cleanly identify which services are configured via Puppet vs. Ansible.
> And how can we do that in the least destructive way possible so as not
> to confuse ourselves and our users in the process.
> Also, I think its work keeping in mind that TripleO was once a multi-
> vendor project with vendors that had different preferences on service
> configuration. Also having the ability to support multiple
> configuration mechanisms in the future could once again present itself
> (thinking of Kubernetes as an example). Keeping in mind there may be a
> conversion period that could well last more than a release or two.
> I suggested a 'services/ansible' directory with mixed responces in our
> #tripleo meeting this week. Any other thoughts on the matter?

I would almost rather see us organize the directories by service
name/project instead of implementation.

Instead of:


We'd have:


(or perhaps even another level of directories to indicate

Personally, such an organization is something I'm more used to. It
feels more similar to how most would expect a puppet module or ansible
role to be organized, where you have the abstraction (service
configuration) at a higher directory level than specific

It would also lend itself more easily to adding implementations only
for specific services, and address the question of if a new top level
implementation directory needs to be created. For example, adding a
services/nova/nova-api-chef.yaml seems a lot less contentious than
adding a top level chef/services/nova-api.yaml.

It'd also be nice if we had a way to mark the default within a given
service's directory. Perhaps services/nova/nova-api-default.yaml,
which would be a new template that just consumes the default? Or
perhaps a symlink, although it was pointed out symlinks don't work in
swift containers. Still, that could possibly be addressed in our plan
upload workflows. Then the resource-registry would point at
nova-api-default.yaml. One could easily tell which is the default
without having to cross reference with the resource-registry.

-- James Slagle

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