Hello All,
I’ve been working on adding support for configurable per-CDN and
per-DeliveryService routing names [1] (what are currently hardcoded/defaulted
to ‘edge’ and ‘tr’ for DNS and HTTP Delivery Services, respectively), and I
have a few things to propose.
1. Add a column to the CDN table for the DNS and HTTP routing names.
I’ve currently been working off the assumption that per-CDN routing names would
be configurable by adding ‘http.routing.name’ and ‘dns.routing.name’ parameters
to a profile of type TR_PROFILE using the ‘CRConfig.json’ config file. To me
this seems like bad UX because the user has to click through multiple steps and
fill in multiple fields in the UI just to change the CDN’s routing names. It
also requires joining a few different tables in the DB just to find the
parameters per-CDN. For that reason, I think it would be better if
‘dns_routing_name’ and ‘http_routing_name’ were added as columns of the ‘cdn’
table, and changing them via the UI would follow the same process as choosing
the CDN’s domain name. Because the routing names would be the CDN-wide
defaults, the ‘Edit CDN’ window feels like the most natural place to put it.
1. Values for per-DeliveryService routing names could live in one of a
couple different areas:
* New columns in the delivery_service table
* Parameters in a DS Profile
As the developer, my vote would be for Option A because it seems like it would
lead to cleaner code in Traffic Ops because the routing names would be
readily-available when handling a DeliveryService. You wouldn’t have to also
fetch its profile then dig through it to find the routing names. A downside
could be that adding columns to an already-overcrowded table isn’t ideal.
Option B is less appealing to me but might have some advantages such as keeping
the number of columns down in the DeliveryService table. However, DS Profiles
currently seem to be geared more towards the Multi-site Origin feature in
generating specific ATS configuration (parent.config) and less towards a “junk
drawer for optional config”. As the routing names would affect the entire DS
and multiple config files, it doesn’t seem right to have it as a profile
parameter using ‘CRConfig.json’ as the config file. I wasn’t around when DS
Profiles were introduced, so if you are more familiar with their purpose/origin
and think this is a good fit for them, I’d like to hear your advice.
1. If per-DeliveryService routing names are not set explicitly for a DS
(i.e. the column is null), then the DS will use the per-CDN routing names as a
default. If the per-CDN routing names are unset, they will default to the
current values of ‘edge’ and ‘tr’. So the lookup hierarchy would be
DS.routing_names -> CDN.routing_names -> default ‘edge/tr’.
I’d like to know what you think of these proposals, and any advice/feedback is
welcome.
Best regards,
Rawlin
[1] https://issues.apache.org/jira/browse/TC-287
