use_backend registry if { hdr_end(host) -i remote.repository.com } { path_beg /v2 }
use_backend registry_auth if { hdr_end(host) -i remote.repository.com } { path_beg /auth }
...
backend registry server registry 127.0.0.1:5000
backend registry_auth server registry_auth 127.0.0.1:5001