Chapter 3. Parameters

Each Heat template in the director’s template collection contains a parameters section. This section defines all parameters specific to a particular overcloud service. This includes the following:

  • overcloud.j2.yaml - Default base parameters
  • roles_data.yaml - Default parameters for composable roles
  • puppet/services/*.yaml - Default parameters for specific services

You can modify the values for these parameters using the following method:

  1. Create an environment file for your custom parameters.
  2. Include your custom parameters in the parameter_defaults section of the environment file.
  3. Include the environment file with the openstack overcloud deploy command.

The next few sections contain examples to demonstrate how to configure specific parameters for services in the puppet/services directory.

3.1. Example 1: Configuring the Timezone

The Heat template for setting the timezone (puppet/services/time/timezone.yaml) contains a TimeZone parameter. If you leave the TimeZone parameter blank, the overcloud sets the time to UTC as a default. The director recognizes the standard timezone names defined in the timezone database /usr/share/zoneinfo/. For example, if you wanted to set your time zone to Japan, you would examine the contents of /usr/share/zoneinfo to locate a suitable entry:

$ ls /usr/share/zoneinfo/
Africa      Asia       Canada   Cuba   EST      GB       GMT-0      HST      iso3166.tab  Kwajalein  MST      NZ-CHAT   posix       right      Turkey     UTC       Zulu
America     Atlantic   CET      EET    EST5EDT  GB-Eire  GMT+0      Iceland  Israel       Libya      MST7MDT  Pacific   posixrules  ROC        UCT        WET
Antarctica  Australia  Chile    Egypt  Etc      GMT      Greenwich  Indian   Jamaica      MET        Navajo   Poland    PRC         ROK        Universal  W-SU
Arctic      Brazil     CST6CDT  Eire   Europe   GMT0     Hongkong   Iran     Japan        Mexico     NZ       Portugal  PST8PDT     Singapore  US         zone.tab

The output listed above includes time zone files, and directories containing additional time zone files. For example, Japan is an individual time zone file in this result, but Africa is a directory containing additional time zone files:

$ ls /usr/share/zoneinfo/Africa/
Abidjan      Algiers  Bamako  Bissau       Bujumbura   Ceuta    Dar_es_Salaam  El_Aaiun  Harare        Kampala   Kinshasa    Lome        Lusaka  Maseru     Monrovia  Niamey       Porto-Novo  Tripoli
Accra        Asmara   Bangui  Blantyre     Cairo       Conakry  Djibouti       Freetown  Johannesburg  Khartoum  Lagos       Luanda      Malabo  Mbabane    Nairobi   Nouakchott   Sao_Tome    Tunis
Addis_Ababa  Asmera   Banjul  Brazzaville  Casablanca  Dakar    Douala         Gaborone  Juba          Kigali    Libreville  Lubumbashi  Maputo  Mogadishu  Ndjamena  Ouagadougou  Timbuktu    Windhoek

Add the entry in an environment file to set your timezone to Japan:

parameter_defaults:
  TimeZone: 'Japan'

3.2. Example 2: Enabling Networking Distributed Virtual Routing (DVR)

The Heat template for the OpenStack Networking (neutron) API (puppet/services/neutron-api.yaml) contains a parameter to enable and disable Distributed Virtual Routing (DVR). The default for the parameter is false. However, you can enable it using the following in an environment file:

parameter_defaults:
  NeutronEnableDVR: true

3.3. Example 3: Configuring RabbitMQ File Descriptor Limit

For certain configurations, you might need to increase the file descriptor limit for the RabbitMQ server. The puppet/services/rabbitmq.yaml Heat template allows you to set the RabbitFDLimit parameter to the limit you require. Add the following to an environment file.

parameter_defaults:
  RabbitFDLimit: 65536

3.4. Example 4: Enabling and Disabling Parameters

In some case, you might need to initially set a parameters during a deployment, then disable the parameter for a future deployment operation, such as updates or scaling operations. For example, to include a custom RPM during the overcloud creation, you would include the following:

parameter_defaults:
  DeployArtifactURLs: ["http://www.example.com/myfile.rpm"]

If you need to disable this parameter from a future deployment, it is not enough to remove the parameter. Instead, you set the parameter to an empty value:

parameter_defaults:
  DeployArtifactURLs: []

This ensures the parameter is no longer set for subsequent deployments operations.

3.5. Identifying Parameters to Modify

Red Hat OpenStack Platform director provides many parameters for configuration. In some cases, you might experience difficulty identifying a certain option to configure and the corresponding director parameter. If there is an option you want to configure through the director, use the following workflow to identify and map the option to a specific overcloud parameter:

  1. Identify the option you aim to configure. Make a note of the service that uses the option.
  2. Check the corresponding Puppet module for this option. The Puppet modules for Red Hat OpenStack Platform are located under /etc/puppet/modules on the director node. Each module corresponds to a particular service. For example, the keystone module corresponds to the OpenStack Identity (keystone).

    • If the Puppet module contains a variable that controls the chosen option, move to the next step.
    • If the Puppet module does not contain a variable that controls the chosen option, then no hieradata exists for this option. If possible, you can set the option manually after the overcloud completes deployment.
  3. Check the director’s core Heat template collection for the Puppet variable in the form of hieradata. The templates in puppet/services/* usually correspond to the Puppet modules of the same services. For example, the puppet/services/keystone.yaml template provides hieradata to the keystone module.

    • If the Heat template sets hieradata for the Puppet variable, the template should also disclose the director-based parameter to modify.
    • If the Heat template does not set hieradata for the Puppet variable, use the configuration hooks to pass the hieradata using an environment file. See Section 4.5, “Puppet: Customizing Hieradata for Roles” for more information on customizing hieradata.

Workflow Example

You might aim to change the notification format for OpenStack Identity (keystone). Using the workflow, you would:

  1. Identify the OpenStack parameter to configure (notification_format).
  2. Search the keystone Puppet module for the notification_format setting. For example:

    $ grep notification_format /etc/puppet/modules/keystone/manifests/*

    In this case, the keystone module manages this option using the keystone::notification_format variable.

  3. Search the keystone service template for this variable. For example:

    $ grep "keystone::notification_format" /usr/share/openstack-tripleo-heat-templates/puppet/services/keystone.yaml

    The output shows the director using the KeystoneNotificationFormat parameter to set the keystone::notification_format hieradata.

The following table shows the eventual mapping:

Director ParameterPuppet HieradataOpenStack Identity (keystone) option

KeystoneNotificationFormat

keystone::notification_format

notification_format

This means setting the KeystoneNotificationFormat in an overcloud’s environment file would set the notification_format option in the keystone.conf file during the overcloud’s configuration.