CDN edge groups are groups of edge servers – your own, and those you subscribe to from the CDN marketplace. They are usually grouped by location, so they represent a pool of servers for a given geographical area. Once you have created an edge group containing edge servers in specific locations, you can then assign the group (or groups) to a specific CDN resource. You need to associate CDN Edge groups with buckets to make them available for users.
PLEASE NOTE: Starting from the OnApp Cloud v3.0, CDN is enabled automatically after adding the first DNS record or CDN resource.