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OpenStack-Ansible Inventory

OpenStack-Ansible uses an included script to generate the inventory of hosts and containers within the environment. This script is called by Ansible through its dynamic inventory functionality.

Generating the Inventory

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


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

The command can also be run manually as follows:

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

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


The dynamic_inventory.py script takes a single argument, --config. If not specified, the default is /etc/openstack_deploy/.


In all versions prior to Mitaka, 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 directories:

  • conf.d
  • env.d

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:


The identity_hosts dictionary defines an Ansible inventory group named identity_hosts containing the three infra hosts. The configuration file etc/openstack_deploy/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 etc/openstack_deploy/env.d/cinder.yml in the container_skel section.


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.


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.

Inspecting and Managing the Inventory

The file scripts/inventory-manage.py is used to produce human readable output based on the /etc/openstack_deploy/openstack_inventory.json file.

The same script can be used to safely remove hosts from the inventory.

Viewing the Inventory

The /etc/openstack_deploy/openstack_inventory.json file is read by default. An alternative file can be specified with --file.

A list of all hosts can be seen with the --list-host/-l argument

To see a listing of hosts and containers by their group, use --list-groups/-g.

To see all of the containers, use --list-containers/-G.

Removing a Host

A host can be removed with the --remove-item/-r parameter.

Use the host’s name as an argument.

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