Glance Caching Enhancements for Edge Cloud

Enhance Glance API Caching such that

a) Update Glance API to interwork with remote Glance Storage-Backends (i.e. specifically Glance Storage-backends configured on another OpenStack cloud/region ... e.g. a Central Cloud's Glance), and to support Glance API Caching when interworking with these remote Glance Storage-Backends

b) Enable the Edge Cloud Glance API Caching to support the ability to locally use those cached images (e.g. nova boot ...) even when network connectivity is lost to the Central Cloud Glance Service
               · i.e. image meta-data is required in order to service a ‘nova boot ...’, and
                               today image meta-data is NOT cached by Glance API Caching.

The proposed solution should generically work between any two Glance Services.
e.g.
               · in a Multi-Region Environment,
               · in a StarlingX Distributed Cloud,
               · etc.

The proposed solution need only deal with the Edge Cloud Glance talking to a single Central Cloud Glance.

NOTE: These potential Glance Caching enhancements were discussed at the edge-computing PTG Meetings in Denver.

NOTE: A specification WILL be written in the next week to detail high-level design approach.