Configuring the inventory¶

In this chapter, you can find the information on how to configure the openstack-ansible dynamic inventory to your needs.

Introduction¶

Common OpenStack services and their configuration are defined by OpenStack-Ansible in the /etc/openstack_deploy/openstack_user_config.yml settings file.

Additional services should be defined with a YAML file in /etc/openstack_deploy/conf.d, in order to manage file size.

The /etc/openstack_deploy/env.d directory sources all YAML files into the deployed environment, allowing a deployer to define additional group mappings. This directory is used to extend the environment skeleton, or modify the defaults defined in the inventory/env.d directory.

To understand how the dynamic inventory works, see Understanding the inventory.

Warning

Never edit or delete the files /etc/openstack_deploy/openstack_inventory.json or /etc/openstack_deploy/openstack_hostnames_ips.yml. This can lead to file corruptions, and problems with the inventory: hosts and container could disappear and new ones would appear, breaking your existing deployment.

Configuration constraints¶

Group memberships¶

When adding groups, keep the following in mind:

A group can contain hosts
A group can contain child groups

However, groups cannot contain child groups and hosts.

The lxc_hosts Group¶

When the dynamic inventory script creates a container name, the host on which the container resides is added to the lxc_hosts inventory group.

Using this name for a group in the configuration will result in a runtime error.

Deploying directly on hosts¶

To deploy a component directly on the host instead of within a container, set the is_metal property to true for the container group in the container_skel section in the appropriate file.

The use of container_vars and mapping from container groups to host groups is the same for a service deployed directly onto the host.

Note

The cinder-volume component is deployed directly on the host by default. See the env.d/cinder.yml file for this example.

Example: Running galera on dedicated hosts¶

For example, to run Galera directly on dedicated hosts, you would perform the following steps:

Modify the container_skel section of the env.d/galera.yml file. For example:

container_skel:
  galera_container:
    belongs_to:
      - db_containers
    contains:
      - galera
    properties:
      is_metal: true

Note

To deploy within containers on these dedicated hosts, omit the is_metal: true property.

Assign the db_containers container group (from the preceding step) to a host group by providing a physical_skel section for the host group in a new or existing file, such as env.d/galera.yml. For example:
```
physical_skel:
  db_containers:
    belongs_to:
      - all_containers
  db_hosts:
    belongs_to:
      - hosts
```
Define the host group (db_hosts) in a conf.d/ file (such as galera.yml). For example:
```
db_hosts:
  db-host1:
    ip: 172.39.123.11
  db-host2:
    ip: 172.39.123.12
  db-host3:
    ip: 172.39.123.13
```
Note

Each of the custom group names in this example (db_containers and db_hosts) are arbitrary. Choose your own group names, but ensure the references are consistent among all relevant files.

Deploying 0 (or more than one) of component type per host¶

When OpenStack-Ansible generates its dynamic inventory, the affinity setting determines how many containers of a similar type are deployed on a single physical host.

Using shared-infra_hosts as an example, consider this openstack_user_config.yml configuration:

shared-infra_hosts:
  infra1:
    ip: 172.29.236.101
  infra2:
    ip: 172.29.236.102
  infra3:
    ip: 172.29.236.103

Three hosts are assigned to the shared-infra_hosts group, OpenStack-Ansible ensures that each host runs a single database container, a single Memcached container, and a single RabbitMQ container. Each host has an affinity of 1 by default, which means that each host runs one of each container type.

If you are deploying a stand-alone Object Storage (swift) environment, you can skip the deployment of RabbitMQ. If you use this configuration, your openstack_user_config.yml file would look as follows:

shared-infra_hosts:
  infra1:
    affinity:
      rabbit_mq_container: 0
    ip: 172.29.236.101
  infra2:
    affinity:
      rabbit_mq_container: 0
    ip: 172.29.236.102
  infra3:
    affinity:
      rabbit_mq_container: 0
    ip: 172.29.236.103

This configuration deploys a Memcached container and a database container on each host, but no RabbitMQ containers.

Omit a service or component from the deployment¶

To omit a component from a deployment, you can use one of several options:

Remove the physical_skel link between the container group and the host group by deleting the related file located in the env.d/ directory.
Do not run the playbook that installs the component. Unless you specify the component to run directly on a host by using the is_metal property, a container is created for this component.
Adjust the Deploying 0 (or more than one) of component type per host to 0 for the host group. Similar to the second option listed here, Unless you specify the component to run directly on a host by using the is_metal property, a container is created for this component.