Where to put SSL validation files when renewing SSL certificates

I need to update the SSL on my self hosted server, and need to do the usual putting a verfication file at the root of the accessible domain, but can’t find where to put the file for it on a running gitlab server, I know I can turn gitlab off and boot up apache/nginx instance and serve it that way, but its a running server and would prefer it to work without down time.

Thanks in advance.