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Generating the Inventory¶
The script that creates the inventory is located at
inventory/dynamic_inventory.py
.
This section explains how ansible runs the inventory, and how you can run it manually to see its behavior.
Executing the dynamic_inventory.py script manually¶
When running an Ansible command (such as ansible
, ansible-playbook
or
openstack-ansible
) Ansible automatically executes the
dynamic_inventory.py
script
and use its output as inventory.
Run the following command:
# from the root folder of cloned OpenStack-Ansible repository
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
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 Ussuri, 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
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 inventory/env.d/cinder.yml
in the
container_skel
section.
For more details, see Configuring the inventory.
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.
Warning
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.
Checking inventory configuration for errors¶
Using the --check
flag when running dynamic_inventory.py
will run the
inventory build process and look for known errors, but not write any files to
disk.
If any groups defined in the openstack_user_config.yml
or conf.d
files
are not found in the environment, a warning will be raised.
This check does not do YAML syntax validation, though it will fail if there are unparseable errors.
Writing debug logs¶
The --debug/-d
parameter allows writing of a detailed log file for
debugging the inventory script’s behavior. The output is written to
inventory.log
in the current working directory.
The inventory.log
file is appended to, not overwritten.
Like --check
, this flag is not invoked when running from ansible.