New data source for the Exoscale.com cloud platform

- dsidentify switches to the new Exoscale datasource on matching DMI name
- New Exoscale datasource added

Signed-off-by: Mathieu Corbin <mathieu.corbin@exoscale.ch>

2 files changed, 69 insertions, 0 deletions

diff --git a/doc/rtd/topics/datasources.rst b/doc/rtd/topics/datasources.rst
index 648c6068..2148cd5e 100644
--- a/doc/rtd/topics/datasources.rst
+++ b/doc/rtd/topics/datasources.rst
@@ -155,6 +155,7 @@ Follow for more information.
    datasources/configdrive.rst
    datasources/digitalocean.rst
    datasources/ec2.rst
+   datasources/exoscale.rst
    datasources/maas.rst
    datasources/nocloud.rst
    datasources/opennebula.rst
diff --git a/doc/rtd/topics/datasources/exoscale.rst b/doc/rtd/topics/datasources/exoscale.rst
new file mode 100644
index 00000000..27aec9cd
--- /dev/null
+++ b/doc/rtd/topics/datasources/exoscale.rst
@@ -0,0 +1,68 @@
+.. _datasource_exoscale:
+
+Exoscale
+========
+
+This datasource supports reading from the metadata server used on the
+`Exoscale platform <https://exoscale.com>`_.
+
+Use of the Exoscale datasource is recommended to benefit from new features of
+the Exoscale platform.
+
+The datasource relies on the availability of a compatible metadata server
+(``http://169.254.169.254`` is used by default) and its companion password
+server, reachable at the same address (by default on port 8080).
+
+Crawling of metadata
+--------------------
+
+The metadata service and password server are crawled slightly differently:
+
+ * The "metadata service" is crawled every boot.
+ * The password server is also crawled every boot (the Exoscale datasource
+   forces the password module to run with "frequency always").
+
+In the password server case, the following rules apply in order to enable the
+"restore instance password" functionality:
+
+ * If a password is returned by the password server, it is then marked "saved"
+   by the cloud-init datasource. Subsequent boots will skip setting the password
+   (the password server will return "saved_password").
+ * When the instance password is reset (via the Exoscale UI), the password
+   server will return the non-empty password at next boot, therefore causing
+   cloud-init to reset the instance's password.
+
+Configuration
+-------------
+
+Users of this datasource are discouraged from changing the default settings
+unless instructed to by Exoscale support.
+
+The following settings are available and can be set for the datasource in system
+configuration (in `/etc/cloud/cloud.cfg.d/`).
+
+The settings available are:
+
+ * **metadata_url**: The URL for the metadata service (defaults to
+   ``http://169.254.169.254``)
+ * **api_version**: The API version path on which to query the instance metadata
+   (defaults to ``1.0``)
+ * **password_server_port**: The port (on the metadata server) on which the
+   password server listens (defaults to ``8080``).
+ * **timeout**: the timeout value provided to urlopen for each individual http
+   request. (defaults to ``10``)
+ * **retries**: The number of retries that should be done for an http request
+   (defaults to ``6``)
+
+
+An example configuration with the default values is provided below:
+
+.. sourcecode:: yaml
+
+   datasource:
+     Exoscale:
+       metadata_url: "http://169.254.169.254"
+       api_version: "1.0"
+       password_server_port: 8080
+       timeout: 10
+       retries: 6