.. _datasource_gce:

Google Compute Engine
=====================

The GCE datasource gets its data from the internal compute metadata server.
Metadata can be queried at the URL
'``http://metadata.google.internal/computeMetadata/v1/``'
from within an instance.  For more information see the `GCE metadata docs`_.

Currently the default project and instance level metadatakeys keys
``project/attributes/sshKeys`` and ``instance/attributes/ssh-keys`` are merged
to provide ``public-keys``.

``user-data`` and ``user-data-encoding`` can be provided to cloud-init by
setting those custom metadata keys for an *instance*.

Configuration
-------------
The following configuration can be set for the datasource in system
configuration (in `/etc/cloud/cloud.cfg` or `/etc/cloud/cloud.cfg.d/`).

The settings that may be configured are:

 * **retries**: The number of retries that should be done for an http request.
   This value is used only after metadata_url is selected. (default: 5)
 * **sec_between_retries**: The amount of wait time between the retries when
   crawling the metadata service.  (default: 1)


An example configuration with the default values is provided below:

.. sourcecode:: yaml

  datasource:
    GCE:
      retries: 5
      sec_between_retries: 1

.. _GCE metadata docs: https://cloud.google.com/compute/docs/storing-retrieving-metadata#querying

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