Chapter 8. Working with custom roles and services

Red Hat OpenStack Platform usually consists of nodes in pre-defined roles, for example, nodes in Controller roles, Compute roles, and different storage role types. Each of these default roles contains a set of services that you define in the core heat template collection. However, the all-in-one Red Hat OpenStack Platform installation runs on a single node that contains all of the OpenStack services. The Standalone.yaml role file in the /usr/share/openstack-tripleo-heat-templates/roles directory is the configuration file that contains all of the services in the all-in-one installation. You can duplicate and modify the Standalone.yaml role file to enable and disable services in your installation.

The Standalone.yaml file contains a list of services in a role Standalone. Use the following example to understand the syntax of this file:

- name: Standalone
  description: |
    A standalone role that includes a minimal set of services. Use this role for testing in a single node configuration with the 'openstack tripleo deploy --standalone' command, or with the 'openstack overcloud deploy' command.
  CountDefault: 1
  tags:
    - primary
    - controller
  disable_constraints: True
  ServicesDefault:
    - OS::TripleO::Services::Aide
    - OS::TripleO::Services::AodhApi
    - OS::TripleO::Services::AodhEvaluator
    ...
    - OS::TripleO::Services::Tuned
    - OS::TripleO::Services::Vpp
    - OS::TripleO::Services::Zaqar

Include this role file in the deployment command to configure your stack with the Standalone role that contains the services that you include in the ServicesDefault: section of the role file:

[stack@all-in-one]$ sudo openstack tripleo deploy --templates -r /usr/share/openstack-tripleo-heat-templates/roles/Standalone.yaml

However, in a production, multi-node Red Hat OpenStack Platform environment, you assign each node with a role that contains a portion of the OpenStack services, rather than including all services on a single node. For example, the default Controller role includes administration, networking, and high availability services, and the default Compute role includes computing services. The default role file in a multi-node environment is the /usr/share/openstack-tripleo-heat-templates/roles_data.yaml file. This file defines the following role types:

Use the following example to understand role syntax in a multi-node environment:

- name: Controller
  description: |
    Controller role that contains all of the services for database, messaging and network functions.
  ServicesDefault:
    - OS::TripleO::Services::AuditD
    - OS::TripleO::Services::CACerts
    - OS::TripleO::Services::CephClient
    ...
- name: Compute
  description: |
    Basic Compute Node role
  ServicesDefault:
    - OS::TripleO::Services::AuditD
    - OS::TripleO::Services::CACerts
    - OS::TripleO::Services::CephClient
    ...

You must include the role file each time you run the deployment command. You can use the -r argument in the deployment command to override this file and use a custom role file:

[stack@all-in-one]$ sudo openstack tripleo deploy --templates -r ~/templates/roles_data-custom.yaml