Improve module documentation and doc cleanup.

This adds lots of config module documentation in a standard format.
It will greatly improve the content at readthedocs.
Additionally:
 * Add a 'doc' env to tox.ini
 * Changed default highlight language for sphinx conf from python to yaml
   most examples in documentation are yaml configs
 * Updated datasource examples to highlight sh code properly

1 files changed, 26 insertions, 0 deletions

diff --git a/cloudinit/config/cc_set_hostname.py b/cloudinit/config/cc_set_hostname.py
index f43d8d5a..c35cefee 100644
--- a/cloudinit/config/cc_set_hostname.py
+++ b/cloudinit/config/cc_set_hostname.py
@@ -18,6 +18,32 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+"""
+Set Hostname
+------------
+**Summary:** set hostname and fqdn
+
+This module handles setting the system hostname and fqdn. If
+``preserve_hostname`` is set, then the hostname will not be altered.
+
+A hostname and fqdn can be provided by specifying a full domain name under the
+``fqdn`` key. Alternatively, a hostname can be specified using the ``hostname``
+key, and the fqdn of the cloud wil be used. If a fqdn specified with the
+``hostname`` key, it will be handled properly, although it is better to use
+the ``fqdn`` config key. If both ``fqdn`` and ``hostname`` are set, ``fqdn``
+will be used.
+
+**Internal name:** per instance
+
+**Supported distros:** all
+
+**Config keys**::
+
+    perserve_hostname: <true/false>
+    fqdn: <fqdn>
+    hostname: <fqdn/hostname>
+"""
+
 from cloudinit import util