[Edge-computing] [edge][glance][mixmatch]: Wiki of the possible architectures for image synchronisation
Greg.Waines at windriver.com
Thu Jun 7 12:23:44 UTC 2018
I had some additional questions/comments on the Image Synchronization Options ( https://wiki.openstack.org/wiki/Image_handling_in_edge_environment ):
One Glance with multiple backends
· In this scenario, are all Edge Clouds simply configured with the one central glance for its GLANCE ENDPOINT ?
o i.e. GLANCE is a typical shared service in a multi-region environment ?
· If so,
how does this OPTION support the requirement for Edge Cloud Operation when disconnected from Central Location ?
Several Glances with an independent synchronization service (PUSH)
· I refer to this as the PUSH model
· I don’t believe you have to ( or necessarily should) rely on the backend to do the synchronization of the images
o i.e. the ‘Synch Service’ could do this strictly through Glance REST APIs
(making it independent of the particular Glance backend ... and allowing the Glance Backends at Central and Edge sites to actually be different)
· I think the ‘Synch Service’ MUST be able to support ‘selective/multicast’ distribution of Images from Central to Edge for Image Synchronization
o i.e. you don’t want Central Site pushing ALL images to ALL Edge Sites ... especially for the small Edge Sites
· Not sure ... but I didn’t think this was the model being used in mixmatch ... thought mixmatch was more the PULL model (below)
One Glance and multiple Glance API Servers (PULL)
· I refer to this as the PULL model
· This is the current model supported in StarlingX’s Distributed Cloud sub-project
o We run glance-api on all Edge Clouds ... that talk to glance-registry on the Central Cloud, and
o We have glance-api setup for caching such that only the first access to an particular image incurs the latency of the image transfer from Central to Edge
· this PULL model affectively implements the location aware synchronization you talk about below, (i.e. synchronise images only to those cloud instances where they are needed)?
In StarlingX Distributed Cloud,
We plan on supporting both the PUSH and PULL model ... suspect there are use cases for both.
From: "Csatari, Gergely (Nokia - HU/Budapest)" <gergely.csatari at nokia.com>
Date: Thursday, June 7, 2018 at 6:49 AM
To: "openstack-dev at lists.openstack.org" <openstack-dev at lists.openstack.org>, "edge-computing at lists.openstack.org" <edge-computing at lists.openstack.org>
Subject: Re: [Edge-computing] [edge][glance][mixmatch]: Wiki of the possible architectures for image synchronisation
I did some work ont he figures and realised, that I have some questions related to the alternative options:
Multiple backends option:
- What is the API between Glance and the Glance backends?
- How is it possible to implement location aware synchronisation (synchronise images only to those cloud instances where they are needed)?
- Is it possible to have different OpenStack versions in the different cloud instances?
- Can a cloud instance use the locally synchronised images in case of a network connection break?
- Is it possible to implement this without storing database credentials ont he edge cloud instances?
Independent synchronisation service:
- If I understood [1<https://mixmatch.readthedocs.io/en/latest/>] correctly mixmatch can help Nova to attach a remote volume, but it will not help in synchronizing the images. is this true?
As I promised in the Edge Compute Group call I plan to organize an IRC review meeting to check the wiki. Please indicate your availability in [2<https://doodle.com/poll/bddg65vyh4qwxpk5>].
From: Csatari, Gergely (Nokia - HU/Budapest)
Sent: Wednesday, May 23, 2018 8:59 PM
To: OpenStack Development Mailing List (not for usage questions) <openstack-dev at lists.openstack.org>; edge-computing at lists.openstack.org
Subject: [edge][glance]: Wiki of the possible architectures for image synchronisation
Here I send the wiki page [1<https://wiki.openstack.org/wiki/Image_handling_in_edge_environment>] where I summarize what I understood from the Forum session about image synchronisation in edge environment , .
Please check and correct/comment.
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