The active proxy is configured via three CNAMEs: url-downloader.eqiad.wikimedia.org and url-downloader.codfw.wikimedia.org to target a specific site and url-downloader.wikimedia.org (which points to eqiad)

To test changes to the URL downloaders on a subset of hosts it would be great to have new CNAME url-downloader-[eqiad|codfw]-next.w.o which can be used to test changes new URL downloaders: In the standard case it would simply point to the current active hosts and some test production hosts and select k8s deployments like mwdebug could use it instead of the regular URL downloader CNAME, but when something needs to be tested we could simply point the -next CNAMEs to the new host.