Add docs about --server (#5713)

* Add docs about --server

* address review comments

* mention server in Docker docs

* correct server URL

* Use prod ACMEv2 example

docs/install.rst

@@ -142,8 +142,11 @@ validation over DNS for popular providers. To use one, just replace
 want to use. For example, to use Certbot's plugin for Amazon Route 53,
 you'd use ``certbot/dns-route53``. You may also need to add flags to
 Certbot and/or mount additional directories to provide access to your
-DNS API credentials. See the :ref:`DNS plugin documentation
-<dns_plugins>`  for more info.
+DNS API credentials as specified in the :ref:`DNS plugin documentation
+<dns_plugins>`. If you would like to obtain a wildcard certificate from
+Let's Encrypt's ACMEv2 server, you'll need to include ``--server
+https://acme-v02.api.letsencrypt.org/directory`` on the command line as
+well.
 
 For more information about the layout
 of the ``/etc/letsencrypt`` directory, see :ref:`where-certs`.

docs/using.rst

@@ -837,6 +837,27 @@ Example usage for DNS-01 (Cloudflare API v4) (for example purposes only, do not
 
 .. _lock-files:
 
+Changing the ACME Server
+========================
+
+By default, Certbot uses Let's Encrypt's initial production server at
+https://acme-v01.api.letsencrypt.org/. You can tell Certbot to use a
+different CA by providing ``--server`` on the command line or in a
+:ref:`configuration file <config-file>` with the URL of the server's
+ACME directory. For example, if you would like to use Let's Encrypt's
+new ACMEv2 server, you would add ``--server
+https://acme-v02.api.letsencrypt.org/directory`` to the command line.
+Certbot will automatically select which version of the ACME protocol to
+use based on the contents served at the provided URL.
+
+If you use ``--server`` to specify an ACME CA that implements a newer
+version of the spec, you may be able to obtain a certificate for a
+wildcard domain. Some CAs (such as Let's Encrypt) require that domain
+validation for wildcard domains must be done through modifications to
+DNS records which means that the dns-01_ challenge type must be used. To
+see a list of Certbot plugins that support this challenge type and how
+to use them, see plugins_.
+
 Lock Files
 ==========