if you open http://videos.mozilla.org/serv you are redirected to http://videos-origin.mozilla.org/serv/ this probably shouldn't be happening; people may not realise they have been shifted to -origin, and share the -origin url instead of the cdn one.
http://videos.mozilla.org/serv/ does not redirect http://videos.mozilla.org/serv (missing trailing slash) does. This is caused by the Apache DirectorySlash option, which redirects from pages missing the trailing slash to include it. It's on by default, for good reasons. The problem is that the CDN sends its requests to videos-origin.mozilla.org... so that's what our server responds with. The CDN doesn't know to translate the redirect in the response, so it just sends it along to the end user. There are several ways to fix this. I think what I'll do is tell the CDN to send requests with a Host header of 'videos-cdn.mozilla.net', and continue to let it pass back the response unmangled. Of course the request itself will still go to videos-origin.mozilla.org, only the Host header will change. I've added this to ServerAlias on the origin server, just waiting on puppet to propagate before changing the setting on the CDN.
Puppet propagated Apache reloaded CDN setting updated... waiting for propagation (up to 1 hr) I have also changed DNS for videos-cdn.mozilla.net, but that's for a different bug (Bug 665620). I have verified that the setting in that place is correct as well.
This is fixed.