Chapter 2. Configuring the Compute service (nova)

As a cloud administrator, you use environment files to customize the Compute (nova) service. Puppet generates and stores this configuration in the /var/lib/config-data/puppet-generated/<nova_container>/etc/nova/nova.conf file. Use the following configuration methods to customize the Compute service configuration, in the following order of precedence:

  1. Heat parameters - as detailed in the Compute (nova) Parameters section in the Overcloud parameters guide. The following example uses heat parameters to set the default scheduler filters, and configure an NFS backend for the Compute service:

    parameter_defaults:
      NovaNfsEnabled: true
      NovaNfsOptions: "context=system_u:object_r:nfs_t:s0"
      NovaNfsShare: "192.0.2.254:/export/nova"
      NovaNfsVersion: "4.2"
      NovaSchedulerEnabledFilters:
        - AggregateInstanceExtraSpecsFilter
        - ComputeFilter
        - ComputeCapabilitiesFilter
        - ImagePropertiesFilter
  2. Puppet parameters - as defined in /etc/puppet/modules/nova/manifests/*:

    parameter_defaults:
      ComputeExtraConfig:
        nova::compute::force_raw_images: True
    Note

    Only use this method if an equivalent heat parameter does not exist.

  3. Manual hieradata overrides - for customizing parameters when no heat or Puppet parameter exists. For example, the following sets the timeout_nbd in the [DEFAULT] section on the Compute role:

    parameter_defaults:
      ComputeExtraConfig:
        nova::config::nova_config:
          DEFAULT/timeout_nbd:
            value: '20'
Warning

If a heat parameter exists, use it instead of the Puppet parameter. If a Puppet parameter exists, but not a heat parameter, use the Puppet parameter instead of the manual override method. Use the manual override method only if there is no equivalent heat or Puppet parameter.

Tip

Follow the guidance in Identifying parameters that you want to modify to determine if a heat or Puppet parameter is available for customizing a particular configuration.

For more information about how to configure overcloud services, see Heat parameters in the Installing and managing Red Hat OpenStack Platform with director guide.