6.14. Customizing Overcloud Pre-Configuration
The Overcloud uses Puppet for the core configuration of OpenStack components. The director provides a set of resources to provide custom configuration after the first boot completes and before the core configuration begins. These resources include:
- OS::TripleO::ControllerExtraConfigPre
- Additional configuration applied to Controller nodes before the core Puppet configuration.
- OS::TripleO::ComputeExtraConfigPre
- Additional configuration applied to Compute nodes before the core Puppet configuration.
- OS::TripleO::CephStorageExtraConfigPre
- Additional configuration applied to CephStorage nodes before the core Puppet configuration.
- OS::TripleO::NodeExtraConfig
- Additional configuration applied to all nodes roles before the core Puppet configuration.
In this example, you first create a basic heat template (
/home/stack/templates/nameserver.yaml) that runs a script to append each node's resolv.conf with a variable nameserver.
heat_template_version: 2014-10-16
description: >
Extra hostname configuration
parameters:
server:
type: string
nameserver_ip:
type: string
DeployIdentifier:
type: string
resources:
ExtraPreConfig:
type: OS::Heat::SoftwareConfig
properties:
group: script
config:
str_replace:
template: |
#!/bin/sh
echo "nameserver _NAMESERVER_IP_" >> /etc/resolv.conf
params:
_NAMESERVER_IP_: {get_param: nameserver_ip}
ExtraPreDeployment:
type: OS::Heat::SoftwareDeployment
properties:
config: {get_resource: ExtraPreConfig}
server: {get_param: server}
actions: ['CREATE','UPDATE']
input_values:
deploy_identifier: {get_param: DeployIdentifier}
outputs:
deploy_stdout:
description: Deployment reference, used to trigger pre-deploy on changes
value: {get_attr: [ExtraPreDeployment, deploy_stdout]}
In this example, the `resources` section contains the following:
- ExtraPreConfig
- This defines a software configuration. In this example, we define a Bash
scriptand Heat replaces_NAMESERVER_IP_with the value stored in thenameserver_ipparameter. - ExtraPreDeployments
- This executes a software configuration, which is the software configuration from the
ExtraPreConfigresource. Note the following:- The
serverparameter is provided by the parent template and is mandatory in templates for this hook. input_valuescontains a parameter calleddeploy_identifier, which stores theDeployIdentifierfrom the parent template. This parameter provides a timestamp to the resource for each deployment update. This ensures the resource reapplies on subsequent overcloud updates.
Next, create an environment file (
/home/stack/templates/pre_config.yaml) that registers your heat template as the OS::TripleO::NodeExtraConfig resource type.
resource_registry: OS::TripleO::NodeExtraConfig: /home/stack/templates/nameserver.yaml parameter_defaults: nameserver_ip: 192.168.1.1
To apply the configuration, add the environment file to the stack when creating or updating the Overcloud. For example:
$ openstack overcloud deploy --templates -e /home/stack/templates/pre_config.yaml
This applies the configuration to all nodes before the core configuration begins on either the initial Overcloud creation or subsequent updates.
Important
You can only register these resources to only one Heat template each. Subsequent usage overrides the heat template to use per resource.
