As it stands now, parent.config could sort of handle that. If a host has no parents or has an origin, it will set it up like a mid. If not, it's going to get the edge cache treatment and parents will be listed for each DS based on the parent cachegroups assigned.
That said, remap.config still functions on "I'm an edge, I'm a mid." So there's still work to be done to get us there 100%. FYI I just tested this against prod database and across the board it did exactly as expected. In a standard two-tier environment the parent.configs were identical to the normal method, and in a single-tier environment the parent.config went from incorrect and unable to handle MSO to correct. This was tested on all edge types, mids, and single tier mids across all our CDNs. The only differences were in header timestamps unless otherwise expected. Derek On 10/3/18, 2:14 PM, "Robert Butts" <[email protected]> wrote: Just out of curiosity, how difficult would it be to similarly support an arbitrary number of tiers, by similarly checking if the parent _isn't_ an origin and doing the reverse? (I'm aware of the hackish and perilous ways TC can go edge-to-edge, I'm wondering about formalized and safe support.) On Wed, Oct 3, 2018 at 11:54 AM Steve Malenfant <[email protected]> wrote: > I haven't tried but I'm +1 for this. > > On Wed, Oct 3, 2018 at 12:59 PM Gelinas, Derek <[email protected]> > wrote: > > > https://github.com/apache/trafficcontrol/pull/2904 > > > > On 10/3/18, 12:25 PM, "Dewayne Richardson" <[email protected]> wrote: > > > > Stating the obvious for posterity, but what is the PR link? > > > > > > -Dew > > > > On Wed, Oct 3, 2018 at 8:47 AM Gelinas, Derek < > > [email protected]> > > wrote: > > > > > All, > > > > > > I’ve put a PR together to add support for single-layer CDNs. > > Currently, > > > edge and mid cache roles are basically hardwired into the code, so > > that > > > when a parent.config file is generated, the rules for edges and > mids > > are > > > always the same. This is fine if you are only using edges and > mids, > > but > > > not so much if you’ve got edges only. MSO is completely > unsupported > > in a > > > config like this, and the parent.config looks like an edge config, > > with > > > each remap listed without parents. This is incorrect. > > > > > > What my PR does is actually very simple. Rather than look at the > > cache > > > type at the various stages of the parent config generation, we look > > at the > > > parent cachegroup types. If both parent cachegroups are either ORG > > type or > > > unassigned, then $is_top_level is set to 1 (default is 0) and the > > variable > > > is passed to the various subroutines that parent_dot_config uses to > > > generate data. These subroutines have been exclusive to > > parent_dot_config > > > since the scope change a while back, so this change does not affect > > any > > > other subs. From there, all decisions about generating > > configuration data > > > are based on whether or not the cache is a top level cache. > > > > > > With this addition we will be able to properly generate parent > > configs for > > > edge-only CDNs, as well as support multisite. A PR is in place > > marked as > > > do not merge to allow review. I intend to add some documentation > > changes > > > and do some heavy testing before I will pursue merging. > > > > > > Derek > > > > > > > > > > > > > > > >
