openstack-ansible/doc/source/reference/inventory.rst

Generating the Inventory

The script that creates the inventory is located at playbooks/inventory/dynamic_inventory.py.

Executing the dynamic_inventory.py script

When running an Ansible command (such as ansible, ansible-playbook or openstack-ansible) Ansible executes the dynamic_inventory.py script and use its output as inventory.

Run the following command:

# from the playbooks directory
inventory/dynamic_inventory.py --config /etc/openstack_deploy/

This invocation is useful when testing changes to the dynamic inventory script.

Inputs

The dynamic_inventory.py takes the --config argument for the directory holding configuration from which to create the inventory. If not specified, the default is /etc/openstack_deploy/.

In addition to this argument, the base environment skeleton is provided in the playbooks/inventory/env.d directory of the OpenStack-Ansible codebase.

Should an env.d directory be found in the directory specified by --config, its contents will be added to the base environment, overriding any previous contents in the event of conflicts.

Note

In all versions prior to , this argument was --file.

The following file must be present in the configuration directory:

• openstack_user_config.yml

Additionally, the configuration or environment could be spread between two additional sub-directories:

• conf.d
• env.d (for environment customization)

The dynamic inventory script does the following:

• Generates the names of each container that runs a service
• Creates container and IP address mappings
• Assigns containers to physical hosts

As an example, consider the following excerpt from openstack_user_config.yml:

identity_hosts:

infra01:

ip: 10.0.0.10

infra02:

ip: 10.0.0.11

infra03:

ip: 10.0.0.12

The identity_hosts dictionary defines an Ansible inventory group named identity_hosts containing the three infra hosts. The configuration file playbooks/inventory/env.d/keystone.yml defines additional Ansible inventory groups for the containers that are deployed onto the three hosts named with the prefix infra.

Note that any services marked with is_metal: true will run on the allocated physical host and not in a container. For an example of is_metal: true being used refer to playbooks/inventory/env.d/cinder.yml in the container_skel section.

Outputs

Once executed, the script will output an openstack_inventory.json file into the directory specified with the --config argument. This is used as the source of truth for repeated runs.

Note

The openstack_inventory.json file is the source of truth for the environment. Deleting this in a production environment means that the UUID portion of container names will be regenerated, which then results in new containers being created. Containers generated under the previous version will no longer be recognized by Ansible, even if reachable via SSH.

The same JSON structure is printed to stdout, which is consumed by Ansible as the inventory for the playbooks.