Flexible Topologies
Blueprint: https://github.com/apache/trafficcontrol/blob/master/blueprints/flexible-topologies.md
Today, a Traffic Control CDN is limited to 2 tiers -- EDGE and MID -- with the option to skip the MID tier for certain Delivery Service types (e.g. HTTP_LIVE and HTTP_NO_CACHE). In addition, a CDN is limited to one global parent hierarchy, which is defined via the parent_cachegroup and secondary_parent_cachegroup fields of cachegroups. Both of these problems limit a CDN's ability to scale with increased demand and changing usage patterns, and providing the ability to add more tiers to a CDN helps it keep up with that growth. A Topology that works well for one set of Delivery Services might not be ideal for a different set of Delivery Services, and a CDN needs the flexibility to provide the best Topology for any given Delivery Service -- with any number of tiers and custom caching hierarchies.
This encompasses the issues to accomplish Self Service Change Integrity, i.e. snapshot-queue automation.
See https://cwiki.apache.org/confluence/display/TC/Self+Service+Change+Integrity
The proposed access control model concept is constructed of two dimensions: Permissions (roles/capabilities) and Scope (tenancy).
More detailed explanation found here:
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=68715910