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Hi,

Thanks for the answers. I’ve added a 4th option and the note to the Quotas.
https://wiki.openstack.org/wiki/Keystone_edge_architectures

Br,
Gerg0

From: Waines, Greg [mailto:Greg.Waines at windriver.com]
Sent: Friday, June 8, 2018 2:31 PM
To: Csatari, Gergely (Nokia - HU/Budapest) <gergely.csatari at nokia.com>; edge-computing at lists.openstack.org
Subject: Re: [Edge-computing] Keystone Edge Architectures

Responses in-lined below,
Greg.

From: "Csatari, Gergely (Nokia - HU/Budapest)" <gergely.csatari at nokia.com<mailto:gergely.csatari at nokia.com>>
Date: Friday, June 8, 2018 at 5:23 AM
To: Greg Waines <Greg.Waines at windriver.com<mailto:Greg.Waines at windriver.com>>, "edge-computing at lists.openstack.org<mailto:edge-computing at lists.openstack.org>" <edge-computing at lists.openstack.org<mailto:edge-computing at lists.openstack.org>>
Subject: RE: [Edge-computing] Keystone Edge Architectures

Hi,

Thanks for the answer.

According to my understanding this is what we tried to describe in the first option.
[Greg]
Ok ... maybe this is me not understanding what ‘federated’ keystone is.
My understanding of federated keystone ( please correct me if I am wrong ):

  *   All clouds run a Keystone Instance (service provider)
  *   But all Keystone Instances leverage the same remote IdentityProvider as the backend for User Authentication
     *   i.e. there is a single remote IdentityProvider with all the user credentials
  *   The Keystone Instances in each cloud must have the MAPPINGs between IdentityProvider user & SAML Assertions
- to – Keystone Project/User/Token/etc.

So is the “API Synchronization” that you mention in this first option, referring to the synchronization of these MAPPINGs ?



We are NOT using keystone federation in StarlingX.

Maybe what we are doing in StarlingX is a fourth option.
Similar to Option 2 – “Keystone database replication” .... but using an “API-based synchronization” and Fernet Key Synchronization to enable use of Tokens across all clouds.

e.g.

Option 4 – Keystone API Synchronization & Fernet Key Synchronization

  *   Every Edge Cloud instance runs its own keystone instance,
  *   Keystone resources are replicated from central site to edge clouds using API-based Synchronization,
     *   i.e. projects, users, groups, domains, ...
  *   Also supporting Fernet Key synchronization and management across Edge Clouds in order to enable Tokens created at any
Edge / Central cloud being able to be used (and authenticated) in any other clouds.


I’ve also added the list of synched data to the wiki: https://wiki.openstack.org/wiki/Keystone_edge_architectures#Replicated_data
[Greg]
And you probably want to put an asterisk (*) by the Quotas items, as similar to Kingbird, we dynamically manage quotas across the Edge Clouds in order to provide Quotas at the Distributed Cloud Level.  I.e. a project that has a quota of 10 instances, can only create 10 instances across ALL Edge Clouds; NOT 10 instances per Edge Cloud.


Is the replication service part of the open sourced StarlingX?
[Greg] Yes.



Thanks,
Gerg0

From: Waines, Greg [mailto:Greg.Waines at windriver.com]
Sent: Thursday, June 7, 2018 1:37 PM
To: Csatari, Gergely (Nokia - HU/Budapest) <gergely.csatari at nokia.com<mailto:gergely.csatari at nokia.com>>; edge-computing at lists.openstack.org<mailto:edge-computing at lists.openstack.org>
Subject: Re: [Edge-computing] Keystone Edge Architectures

Hey Gergely,

Wrt High-Level journaling/synchronization ... I really mean

  *   We are NOT doing some low-level semantic-unaware DB synchronization,
  *   Instead we are doing a more high level, semantic-aware replication of Keystone Resources from the Central Site to ALL the Edge Clouds
     *   we are generally replicating REST API commands for creating/modifying/deleting Keystone Resources between Central Site and ALL the Edge Clouds
        *   although more sophisticated than that, as it supports retries on failures and audits of resources to handle scenarios where Edge Clouds are
disconnected during changes to the Central Site, etc.
     *   the Keystone Resources we are currently synchronizing are: Users, Projects, Roles and Assignments
        *   ... should be doing Groups and Domains as well ... but currently don’t leverage User Groups and only have default Domain in StarlingX
        *   and, will also synchronize Fernet keys so that tokens created on any cloud can be used/validated on any cloud.
  *   This is built on a common synchronization framework for providing common utilities / mechanisms for broadcast of messages to all Edge Clouds, retries, audits, etc
     *   E.g.  we use this framework for also synchronizing
        *   Nova’s – flavors, flavor extra-specs, keypairs, quotas
        *   Neutron’s – security groups, security group rules
        *   Cinder’s - quotas

Greg.


From: "Csatari, Gergely (Nokia - HU/Budapest)" <gergely.csatari at nokia.com<mailto:gergely.csatari at nokia.com>>
Date: Thursday, June 7, 2018 at 4:15 AM
To: Greg Waines <Greg.Waines at windriver.com<mailto:Greg.Waines at windriver.com>>, "edge-computing at lists.openstack.org<mailto:edge-computing at lists.openstack.org>" <edge-computing at lists.openstack.org<mailto:edge-computing at lists.openstack.org>>
Subject: RE: [Edge-computing] Keystone Edge Architectures

Hi,

What do you mean by high level journaling / syncrronsation?

For me one of the basic differences between option 1 and 2 is the understanding of the data semantics during the synchronisaiton in case of option 1 and synchronising blobs of data in case of option 2.

Can you share what data do you synchronise between the Keystone instances? This is also a piece of information what we are looking for.

Thanks,
Gerg0

From: Waines, Greg [mailto:Greg.Waines at windriver.com]
Sent: Wednesday, June 6, 2018 3:44 PM
To: edge-computing at lists.openstack.org<mailto:edge-computing at lists.openstack.org>
Subject: [Edge-computing] Keystone Edge Architectures

Hey ... just taking a look at the options in https://wiki.openstack.org/wiki/Keystone_edge_architectures .

For the first option, i.e. ‘Several keystone instances with federation with API synchronsation’

  *   I am assuming that the Keystone Instance at each Edge Cloud Instance is communicating with a non-local central Identity Provider
  *   If this is the case, the concern list above related to operability with no connectivity
     *   i.e. “There may be significant times with no connectivity and all functions (e.g. autoscaling) must continue to function”

In the ‘Distributed Cloud’ sub-project of the StarlingX project
( i.e. see summit presentation @ https://www.openstack.org/videos/vancouver-2018/edge-computing-operations-day-1-deployment-and-day-2-management )

  *   our initial keystone approach is simply the standard multi-region centralized shared keystone,
so no scalability and no autonomy for edge clouds on loss of connectivity,
  *
  *   BUT we are currently taking more of the ‘second option’ approach (i.e. ‘Keystone database replication’) ... with some additions
i.e.
     *   Every Edge Cloud instance runs its own keystone instance,
     *   Keystone resources are replicated from central site to edge clouds using our distribute-cloud-replication-framework,
        *   i.e. projects, users, groups, domains, roles, ...
        *   ( i.e. not a low-level DB synchronization ... more a high-level journaling / synchronization of resources )
     *   AND
     *   Also supporting Fernet Key synchronization and management across Edge Clouds in order to enable Tokens created at any
Edge / Central cloud being able to be used (and authenticated) in any other clouds.
        *   Required for some distributed services scenarios,
e.g. glance-api  pulling from a remote glance-registry, etc.     (likely for future scenarios we don’t currently understand).

Comments ?

Greg.
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