Hi Vish,

I am sorry as I am proposing just a solution approach below but no code so far. 

### Problem and Requirement ###
As per the problem description it seems to me that "Martha, the owner of 
ProductionIT" is not a cloud provider (correct me if wrong) and she uses 
someone else cloud infrastructure (like public cloud) to provide services to 
multiple Enterprise clients.

After reading further it seems to me that we want different administrative 
boundaries and isolation among them, so that "Joe can manage/mess-up resource 
for WidgetMaster and Sam for SuperDevShop but not each other" at the same time 
"Martha should be allowed to manage resources from both".

### Requirements based on my understanding ###
1. Joe can manage/mess-up resource for WidgetMaster and Sam for SuperDevShop 
but not each other.
2. Martha should be able to manage resources from both.

### Solution ### (*This solution is backed-up by production working 
implementation*)

In a nutshell, We need ability to setup hierarchicical administrative 
boundaries within a cloud deployment, so that multiple service providers (like  
Martha) can be created and have administrative privilege across multiple 
domains which falls under their administrative boundary.

Note: There will be only one level of hierarchy as multi level hierarchy is 
complex to implement and does not perform well. Give that, 
"Martha/ProductionIT" will be at root of hierarchy, Joe and Sam will stand at 
leaf of the hierarchy.  

(Solution for Req#1) Keystone has concept of domains which is nothing but a 
notion of an administrative boundary where admin of one domain is allowed to 
manage resources within a specific domain but not across domains, provided 
correct policy is in place. This is already in place so there will be no change 
needed to support Req #1.

(Solution for Req#2)
We can extend the notion of domains further to define a root (parent/super) 
domain and leaf (child/sub) domains, one set of root and leaf domains will 
define a hierarchicical administrative boundary. Glue between root and leafs 
will be different roles, that way "Matha" can become "NovaAdmin" (or any other 
role) in WidgetMaster or SuperDevShop.


### Pros ###
Complete IAM based solution.
More logically fits in hierarchicical model.
Absolutely no (or minimal) changes to services (Nova, Swift ....)

### Cons ###
Most of the changes is needed in Keystone and its data model (Domain, Roles).
Some change required in OSLO policy engine for policy evaluation.
Service (Nova, Swift ....) may have define new roles.


Let me know if I am not making sense here or have any questions.

 
Arvind

-----Original Message-----
From: Vishvananda Ishaya [mailto:vishvana...@gmail.com] 
Sent: Monday, February 03, 2014 2:58 PM
To: OpenStack Development Mailing List (not for usage questions)
Subject: [openstack-dev] [keystone][nova] Re: Hierarchicical Multitenancy 
Discussion

Hello Again!

At the meeting last week we discussed some options around getting true 
multitenancy in nova. The use case that we are trying to support can be 
described as follows:

"Martha, the owner of ProductionIT provides it services to multiple Enterprise 
clients. She would like to offer cloud services to Joe at WidgetMaster, and Sam 
at SuperDevShop. Joe is a Development Manager for WidgetMaster and he has 
multiple QA and Development teams with many users. Joe needs the ability create 
users, projects, and quotas, as well as the ability to list and delete 
resources across WidgetMaster. Martha needs to be able to set the quotas for 
both WidgetMaster and SuperDevShop; manage users, projects, and objects across 
the entire system; and set quotas for the client companies as a whole. She also 
needs to ensure that Joe can't see or mess with anything owned by Sam."

As per the plan I outlined in the meeting I have implemented a Proof-of-Concept 
that would allow me to see what changes were required in nova to get scoped 
tenancy working. I used a simple approach of faking out heirarchy by prepending 
the id of the larger scope to the id of the smaller scope. Keystone uses uuids 
internally, but for ease of explanation I will pretend like it is using the 
name. I think we can all agree that 'orga.projecta' is more readable than 
'b04f9ea01a9944ac903526885a2666dec45674c5c2c6463dad3c0cb9d7b8a6d8'.

The code basically creates the following five projects:

orga
orga.projecta
orga.projectb
orgb
orgb.projecta

I then modified nova to replace everywhere where it searches or limits policy 
by project_id to do a prefix match. This means that someone using project 
'orga' should be able to list/delete instances in orga, orga.projecta, and 
orga.projectb.

You can find the code here:

  
https://github.com/vishvananda/devstack/commit/10f727ce39ef4275b613201ae1ec7655bd79dd5f
  
https://github.com/vishvananda/nova/commit/ae4de19560b0a3718efaffb6c205c7a3c372412f

Keeping in mind that this is a prototype, but I'm hoping to come to some kind 
of consensus as to whether this is a reasonable approach. I've compiled a list 
of pros and cons.

Pros:

  * Very easy to understand
  * Minimal changes to nova
  * Good performance in db (prefix matching uses indexes)
  * Could be extended to cover more complex scenarios like multiple owners or 
multiple scopes

Cons:

  * Nova has no map of the hierarchy
  * Moving projects would require updates to ownership inside of nova
  * Complex scenarios involving delegation of roles may be a bad fit
  * Database upgrade to hierarchy could be tricky

If this seems like a reasonable set of tradeoffs, there are a few things that 
need to be done inside of nova bring this to a complete solution:

  * Prefix matching needs to go into oslo.policy
  * Should the tenant_id returned by the api reflect the full 'orga.projecta', 
or just the child 'projecta' or match the scope: i.e. the first if you are 
authenticated to orga and the second if you are authenticated to the project?
  * Possible migrations for existing project_id fields
  * Use a different field for passing ownership scope instead of overloading 
project_id
  * Figure out how nested quotas should work
  * Look for other bugs relating to scoping

Also, we need to decide how keystone should construct and pass this information 
to the services. The obvious case that could be supported today would be to 
allow a single level of hierarchy using domains. For example, if domains are 
active, keystone could pass domain.project_id for ownership_scope. This could 
be controversial because potentially domains are just for grouping users and 
shouldn't be applied to projects.

I think the real value of this approach would be to allow nested projects with 
role inheritance. When keystone is creating the token, it could walk the tree 
of parent projects, construct the set of roles, and construct the 
ownership_scope as it walks to the root of the tree.

Finally, similar fixes will need to be made in the other projects to bring this 
to a complete solution.

Please feel free to respond with any input, and we will be having another 
Hierarchical Multitenancy Meeting on Friday at 1600 UTC to discuss.

Vish

On Jan 28, 2014, at 10:35 AM, Vishvananda Ishaya <vishvana...@gmail.com> wrote:

> Hi Everyone,
> 
> I apologize for the obtuse title, but there isn't a better succinct term to 
> describe what is needed. OpenStack has no support for multiple owners of 
> objects. This means that a variety of private cloud use cases are simply not 
> supported. Specifically, objects in the system can only be managed on the 
> tenant level or globally.
> 
> The key use case here is to delegate administration rights for a group of 
> tenants to a specific user/role. There is something in Keystone called a 
> "domain" which supports part of this functionality, but without support from 
> all of the projects, this concept is pretty useless.
> 
> In IRC today I had a brief discussion about how we could address this. I have 
> put some details and a straw man up here:
> 
> https://wiki.openstack.org/wiki/HierarchicalMultitenancy
> 
> I would like to discuss this strawman and organize a group of people to get 
> actual work done by having an irc meeting this Friday at 1600UTC. I know this 
> time is probably a bit tough for Europe, so if we decide we need a regular 
> meeting to discuss progress then we can vote on a better time for this 
> meeting.
> 
> https://wiki.openstack.org/wiki/Meetings#Hierarchical_Multitenancy_Meeting
> 
> Please note that this is going to be an active team that produces code. We 
> will *NOT* spend a lot of time debating approaches, and instead focus on 
> making something that works and learning as we go. The output of this team 
> will be a MultiTenant devstack install that actually works, so that we can 
> ensure the features we are adding to each project work together.
> 
> Vish


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