I have multiple web applications running with different keytabs and gssproxy. I use gssproxy's sockets to differentiate between them. For that, I need to pass the GSSPROXY_SOCKET environment variable to mod_auth_gssapi, and I can't find a way to do it. I've tried:

• setting one in /etc/systemd/system/httpd.service.d/, that works fine but I can't differentiate between the web apps running in the same apache
• using SetEnv, which is documented not to work, and indeed it doesn't
• using SetEnvIf, it doesn't work either (I tried SetEnvIf Host app.example.com GSSPROXY_SOCKET=/var/lib/gssproxy/app.sock)
• using RewriteRule, and it doesn't work either. I tried RewriteCond %{HTTP_HOST} app.example.com \n RewriteRule .* - [E=GSSPROXY_SOCKET:/var/lib/gssproxy/app.sock]. I did check with increased logging that the rule was matching on the request.

Is there a way to pass an environment variable to mod_auth_gssapi, that is dependent on the virtualhost or even the request path? If so, it would be great if it could be added to the docs (here and/or in gssproxy's Apache doc). Thanks!