openstack team mailing list archive

[Andrew Clay Shafer <acs@xxxxxxxxxxxxxxxx>]

On Thu, Jan 26, 2012 at 8:56 PM, Andrew Bogott <abogott@xxxxxxxxxxxxx>wrote:

>  Andrew --
>
> Thanks for your comments.  I'm going to start with a screenshot for
> context:
>
> http://bogott.net/misc/osmpuppet.png
>
> That's what it looks like when you configure an instance using Open Stack
> Manager, which is WikiMedia's VM management interface.  My main priority
> for adding puppet support to Nova is to facilitate the creation and control
> of a GUI much like that one.
>


Can you explain how your solution works now? You want to inject data into
the VMs in the proposal, but outside of designating the puppet master, all
the data for variables and classes should be changes to the puppet master,
not the instances. That's kind of the whole point of the puppet master.

One thing you really seem to want is RBAC for the nova users.

How are you getting the names for the recipes into your system? Is that
sync with what is on the puppet master somehow or you are going to do data
entry and it's all string matching?

On 1/26/12 5:03 PM, Andrew Clay Shafer wrote:
>
>
>  I'd also like to see more of a service oriented approach and avoid adding
> tables to nova if possible.
>
>  I'm not sure the best solution is to come up with a generic service for
> $configuration_manager for nova core. I'd rather see these implemented as
> optional first class extensions.
>
> This sounds intriguing, but I'll plead ignorance here; can you tell me
> more about what this would look like, or direct me to an existing analogous
> service?
>

I don't think there is a good existing example, but I know if the defacto
way to add functionality in nova is to add tables to the db, that's the
path to operational and maintenance hell.

That's not just for this integration, but in general.

For openstack to become what it should be, Nova shouldn't be a monolithic
app on a database.

Even if you wanted to run this on the same node, it probably shouldn't be
tables in the same database. It should be a separate services with it's own
db user and scheme then be integrated by apis or maybe adding to wsgi.

 What are you going to inject into the instances exactly? Where does the
> site.pp live?
>
> This is the question I'm hoping to get feedback on.  Either nova can
> generate a fully-formed site.pp and inject that, or it can pass config
> information as metadata, in which case an agent would need to be running on
> the guest which would do the work of generating the site.pp.  I certainly
> prefer the former but I'm not yet clear on whether or not file injection is
> widely supported.
>

I'm confused how you want to run puppet exactly. The site.pp would
typically live on the puppet master.

Can you explain more about what you are thinking or how your current
solution works?

 I haven't thought about this that much yet, but off the top of my head,
> but if the instances already have puppet clients and are configured for the
> puppet master, then the only thing you should need to interact with is the
> puppet master.
>
>
> It's definitely the case that all of this could be done via LDAP or the
> puppet master and involve no Nova action at all; that's how WikiMedia's
> system works now.  My aim is to consolidate the many ways we currently
> interact with instances so that we delegate as much authority to Nova as
> possible.  That strikes me as generally worthwhile, but you're welcome to
> disagree :)
>

I think it would be sweet if nova and the dashboard (and probably keystone
too) had a standardized way to add integrated functionality. I don't
believe nova core should be reimplementing/duplicating functionality and
logic in other systems.

The goal of interacting with the instances through a shared interface is a
good one, I'm not against that, I just want to see less deep coupling to
accomplish it.



>  I'm not a fan of the Available, Unavailable, Default, particularly
> because you are managing state of something that may not be true on the
> puppet master.
>
> I may be misunderstanding you, or my blueprint may be unclear.  Available,
> Unavailable, and Default don't refer to the availability of classes on the
> puppet master; rather, they refer to whether or not a class is made
> available to a nova user for a given instance.  An 'available' class would
> appear in the checklist in my screenshot.  An Unavailable class would not.
> A 'default' class would appear, and be pre-checked.  In all three cases the
> class is presumed to be present on the puppet master.
>

I already asked this, but what keeps that in sync with the puppet master?

Personally, I'd rather see an integration that has a per user configuration
to a puppet master that stays in sync than the RBAC per module.

>  I also think managing a site.pp is going to be inferior to providing an
> endpoint that can act as an eternal node tool for the puppet master.
> http://docs.puppetlabs.com/guides/external_nodes.html
>
> In which case nova would interact directly with the puppet master for
> configuration purposes?  (I don't hate that idea, just asking for
> clarification.)
>

That's puppet's model. Whether you use a site.pp, or external nodes. I'm
unclear how you want to do it. Can you explain how your system works now?

> One other point, that you might have thought of, but I don't see anywhere
> on the wiki is how to handle the ca/certs for the instances.
>
> I believe this (and your subsequent question) falls under the heading of "
> Instances are presumed to know any puppet config info they need at creation
> time (e.g. how to contact the puppet master). "  Important, but outside the
> scope of this design :)
>

Thinking through this is actually critical for any standardized puppet
integration in my opinion. The solution is a prerequisite before
considering anything else.

>  Just to reiterate, I'd love to see deeper configuration management
> integrations (because I think managing instances without them is it's own
> hell), but I'm not convinced it should be part of core nova per se.
>
>  So that I understand your terminology... are extensions like the quotas
> or floating ips considered 'core nova'?
>

There is not a bright line especially with the way things have evolved to
now, but I would say floating IPs should definitely be core functionality.
Quotas may be debatable, but I think it is defensible, though part of me
feels like some of that kind of permission functionality might be better
decoupled.

Thanks again for your input!  Clearly it would be best to hash this out at
> the design summit, but I'm hoping to get at least a bit of coding done
> before April :)
>

I hope to be there. I do like the idea, I just want to do what's best for
OpenStack.

Regards,
Andrew