Configuring a reverse proxy with ArcGIS Enterprise: same url for Portal and Server supported?

[Jay_Gregory]

I have inherited an ArcGIS Enterprise 10.9 instance - it has been configured with a reverse proxy instead of ArcGIS WebAdaptor.  Both the Portal AND Server have been placed under the same URL - https://arcgis.mydomain.com/arcgis.

So for example going to Portal homepage is https://arcgis.mydomain.com/arcgis/home and going to Server REST endpoint is https://arcgis.mydomain.com/arcgis/rest/services.  

I know this URL structure (using the same context for Portal and Server) is not supported using WebAdaptor, but I have not been able to figure out if its supported with a reverse proxy.  I have poked around a little and haven't noticed any big issues and nothing seems broken but the site isn't heavily utilized yet either.  

My questions are:

1. Is this setup valid / supported?

2. If not, what potential issues can it cause.  i.e. where can I look for and validate problems. 

3. If so, what other Enterprise related configurations are necessary - WebContextURL settings and the like?

Thx

[Scott_Tansley]

have you had a good read of this:

Integrate your portal with a reverse proxy or load balancer—Portal for ArcGIS | Documentation for Ar...

and

Configure a reverse proxy server with ArcGIS Server—ArcGIS Server | Documentation for ArcGIS Enterpr...

The rules seem to depend on which Reverse Proxy you're using and it's capability.  You haven't mentioned which proxy so it's hard to be a bit more specific.  If this was a manual build of Enterprise, rather than from a builder, then I'd consider trying to push Web Adaptors in if you haven't created content.  It's a cleaner build and eminently more supportable (simple) in my opinion.

[Jay_Gregory]

Thanks - I had read through but since I'm not a load balancer expert I might have not read as thoroughly 🙂

So the only mention I could find is in the Portal section: 

"When not using the ArcGIS Web Adaptor, the default context (/arcgis) must be used for the site. When integrating multiple Portal for ArcGIS and ArcGIS Server sites on the same layer 3/4 load balancer, a unique DNS record should be used for each site and Server Name Identification (SNI) used to route traffic to the appropriate back-end targets."

So what I can take away from this is if we're using a layer 7 load balancer, using the same context is supported - it is not supported with a layer 3/4 load balancer.  Still don't quite understand the implications but good to know.  Wish this was stated more explicitly somewhere, and cross referenced in the Server section as well.  

I agree with WebAdaptor - I'm am much more comfortable in that environment, especially with HA or multi-node sites.  Unfortunately at this point it is out of my control somewhat - we're using AWS and I think a ALB is easier for IT to maintain than Apache w/ 3rd part (i.e. esri) app installed.