doc: Add config info to ec2, openstack and cloudstack datasource docs

Also document instance-data.json on the top-level datasource topic page.

1 files changed, 20 insertions, 6 deletions

diff --git a/doc/rtd/topics/datasources/cloudstack.rst b/doc/rtd/topics/datasources/cloudstack.rst
index 225093a1..a3101ed7 100644
--- a/doc/rtd/topics/datasources/cloudstack.rst
+++ b/doc/rtd/topics/datasources/cloudstack.rst
@@ -4,7 +4,9 @@ CloudStack
 ==========
 
 `Apache CloudStack`_ expose user-data, meta-data, user password and account
-sshkey thru the Virtual-Router. For more details on meta-data and user-data,
+sshkey thru the Virtual-Router. The datasource obtains the VR address via
+dhcp lease information given to the instance.
+For more details on meta-data and user-data,
 refer the `CloudStack Administrator Guide`_. 
 
 URLs to access user-data and meta-data from the Virtual Machine. Here 10.1.1.1
@@ -18,14 +20,26 @@ is the Virtual Router IP:
 
 Configuration
 -------------
+The following configuration can be set for the datasource in system
+configuration (in `/etc/cloud/cloud.cfg` or `/etc/cloud/cloud.cfg.d/`).
 
-Apache CloudStack datasource can be configured as follows:
+The settings that may be configured are:
 
-.. code:: yaml
+ * **max_wait**:  the maximum amount of clock time in seconds that should be
+   spent searching metadata_urls.  A value less than zero will result in only
+   one request being made, to the first in the list. (default: 120)
+ * **timeout**: the timeout value provided to urlopen for each individual http
+   request.  This is used both when selecting a metadata_url and when crawling
+   the metadata service. (default: 50)
 
-    datasource:
-      CloudStack: {}
-      None: {}
+An example configuration with the default values is provided below:
+
+.. sourcecode:: yaml
+
+  datasource:
+   CloudStack:
+    max_wait: 120
+    timeout: 50
     datasource_list:
       - CloudStack