Dependency cycle between certbot and nginx is not obvious.

[MSavoritias <email@msavoritias.me>]

Hey,


I spent the better part of the day today trying to debug an error that 
was happening while deploying a server with two server names in the 
nginx field.

My config was:

      (service certbot-service-type
           (certbot-configuration
            (certificates
         (list
          (certificate-configuration
           ;; The first domain provided will be the subject CN of the 
certificate, and all domains will be Subject Alternative Names on the 
certificate.
           (domains '("joinxmpp.org" "www.joinxmpp.org")))))))
      (service nginx-service-type
           (nginx-configuration
            (server-blocks
         (list (nginx-server-configuration
                (server-name '("joinxmpp.org www.joinxmpp.org"))
                (ssl-certificate "/etc/certs/joinxmpp.org/fullchain.pem")
                (ssl-certificate-key "/etc/certs/joinxmpp.org/privkey.pem")
                (locations
             (list
              (nginx-location-configuration
               (uri "/support")
               (body '("return 302 
\"https://chat.joinjabber.org/#/guest?join=support\";")))))))))))


turns out that this cant be deployed at once on the server. although it 
is correct. The reason is that certbot/letsencrypt will complain with 
the message:

Hint: The Certificate Authority failed to download the temporary 
challenge files created by Certbot. Ensure that the listed domains serve 
their content from the provided --webroot-path/-w and that files created 
there can be downloaded from the internet.


Mind you this error appeared on only one of the domains not both.

This was solved by running the system once with certbot. Then rebooting 
with the nginx service. That idea appear to me after i found a mailing 
list thread from 5 years ago saying that there is a dependency cycle 
between nginx and certbot and they cant run at the same time the first time.


The reason I am sending an email is because I am not sure if this is 
something that could be fixed somehow, or if this is unavoidable and i 
should just send a patch revising the docs slightly to suggest that if 
an nginx service is used with multiple domains in the server name, you 
should start the system once with certbot and then reboot with nginx.


MSavoritias