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 file /etc/openstack_deploy/openstack_inventory.json. This can lead to problems with the inventory: existng hosts and containers will be unmanaged and new ones will be generated instead, 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.

You can also use the no_containers option to specify a host that will have all services deployed on metal inside of it.

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 all controllers on metal¶

For example, if you’d like to run all your controllers on metal, you would have the following inside your openstack_user_config.yml.

infra_hosts:
  infra1:
    ip: 172.39.123.11
    no_containers: true
  infra2:
    ip: 172.39.123.12
    no_containers: true
  infra3:
    ip: 172.39.123.13
    no_containers: true

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.

Adding virtual nest groups¶

If you want to create a custom group for arbitrary grouping of hosts and containers within these hosts but skip the generation of any new containers, you should use is_nest property under container_skel and skip defining belongs_to structure. is_nest property will add host-containers as children to such a group.

Example: Defining Availability Zones¶

A good example of how is_nest property can be used is describing Availability Zones. As when operating multiple AZs it’s handy to define AZ-specific variables, like AZ name, for all hosts in this AZ. And leveraging group_vars is best way of ensuring that all hosts that belong to same AZ have same configuration applied.

Let’s assume you have 3 controllers and each of them is placed in different Availability Zones. There is also a compute node in each Availability Zone. And we want each host or container that is placed physically in a specific AZ be part of it’s own group (ie azN_all)

In order to achieve that we need:

Define host groups in conf.d or openstack_user_config.yml to assign hosts accordingly to their Availability Zones:

az1-infra_hosts: &infra_az1
  az1-infra1:
    ip: 172.39.123.11

az2-infra_hosts: &infra_az2
  az2-infra2:
    ip: 172.39.123.12

az3-infra_hosts: &infra_az3
  az3-infra3:
    ip: 172.39.123.13

shared-infra_hosts: &controllers
  <<: *infra_az1
  <<: *infra_az2
  <<: *infra_az3

az1-compute_hosts: &computes_az1
  az1-compute01:
    ip: 172.39.123.100

az2-compute_hosts: &computes_az2
  az2-compute01:
    ip: 172.39.123.150

az3-compute_hosts: &computes_az3
  az3-compute01:
    ip: 172.39.123.200

compute_hosts:
  <<: *computes_az1
  <<: *computes_az2
  <<: *computes_az3

az1_hosts:
  <<: *computes_az1
  <<: *infra_az1

az2_hosts:
  <<: *computes_az2
  <<: *infra_az2

az3_hosts:
  <<: *computes_az3
  <<: *infra_az3

Create env.d/az.yml file that will leverage is_nest property and allow all infra containers to be part of the AZ group as well

component_skel:
  az1_containers:
    belongs_to:
      - az1_all
  az1_hosts:
    belongs_to:
      - az1_all

  az2_containers:
    belongs_to:
      - az2_all
  az2_hosts:
    belongs_to:
      - az2_all

  az3_containers:
    belongs_to:
      - az3_all
  az3_hosts:
    belongs_to:
      - az3_all

container_skel:
  az1_containers:
    properties:
      is_nest: True
  az2_containers:
    properties:
      is_nest: True
  az3_containers:
    properties:
      is_nest: True

Now you can leverage group_vars file to apply a variable to all containers and bare metal hosts in AZ. For example /etc/openstack_deploy/group_vars/az1_all.yml:
```
---
az_name: az1
cinder_storage_availability_zone: "{{ az_name }}"
```

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 Adding virtual nest groups 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.

Configuring the inventory