Datasource creation

There are multiple ways to provide user data, metadata, and vendor data, and each cloud solution prefers its own way. A datasource abstract base class defines a single interface to interact with the different clouds. Each cloud implementation must inherit from this base class to use this shared functionality and interface. See cloud-init/sources/__init__.py to see this class.

If you are interested in adding a new datasource for your cloud platform you will need to do all of the following:

Identify a mechanism for positive identification of the platform

It is good practice for a cloud platform to positively identify itself to the guest. This allows the guest to make educated decisions based on the platform on which it is running. On the x86 and arm64 architectures, many clouds identify themselves through DMI data. For example, Oracle’s public cloud provides the string 'OracleCloud.com' in the DMI chassis-asset field.

Cloud-init-enabled images produce a log file with details about the platform. Reading through this log in /run/cloud-init/ds-identify.log may provide the information needed to uniquely identify the platform. If the log is not present, you can generate it by running from source ./tools/ds-identify or the installed location /usr/lib/cloud-init/ds-identify.

The mechanism used to identify the platform will be required for the ds-identify and datasource module sections below.

Add datasource module cloudinit/sources/DataSource<CloudPlatform>.py

We suggest you start by copying one of the simpler datasources such as DataSourceHetzner.

Add tests for datasource module

Add a new file with some tests for the module to cloudinit/sources/test_<yourplatform>.py. For example, see cloudinit/sources/tests/test_oracle.py

Update ds-identify

In systemd systems, ds-identify is used to detect which datasource should be enabled, or if cloud-init should run at all. You’ll need to make changes to tools/ds-identify.

Add tests for ds-identify

Add relevant tests in a new class to tests/unittests/test_ds_identify.py. You can use TestOracle as an example.

Add your datasource name to the built-in list of datasources

Add your datasource module name to the end of the datasource_list entry in cloudinit/settings.py.

Add your cloud platform to apport collection prompts

Update the list of cloud platforms in cloudinit/apport.py. This list will be provided to the user who invokes ubuntu-bug cloud-init.

Enable datasource by default in Ubuntu packaging branches

Ubuntu packaging branches contain a template file, debian/cloud-init.templates, which ultimately sets the default datasource_list when installed via package. This file needs updating when the commit gets into a package.

Add documentation for your datasource

You should add a new file in doc/datasources/<cloudplatform>.rst.