6.15. Customizing Overcloud Post-Configuration
A situation might occur where you have completed the creation of your Overcloud but want to add additional configuration, either on initial creation or on a subsequent update of the Overcloud. In this case, you use the
OS::TripleO::NodeExtraConfigPost resource to apply configuration using the standard OS::Heat::SoftwareConfig types. This applies additional configuration after the main Overcloud configuration completes.
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:
servers:
type: json
nameserver_ip:
type: string
DeployIdentifier:
type: string
resources:
ExtraConfig:
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}
ExtraDeployments:
type: OS::Heat::SoftwareDeployments
properties:
config: {get_resource: ExtraConfig}
servers: {get_param: servers}
actions: ['CREATE','UPDATE']
input_values:
deploy_identifier: {get_param: DeployIdentifier}
In this example, the `resources` section contains the following:
- ExtraConfig
- This defines a software configuration. In this example, we define a Bash
scriptand Heat replaces_NAMESERVER_IP_with the value stored in thenameserver_ipparameter. - ExtraDeployments
- This executes a software configuration, which is the software configuration from the
ExtraConfigresource. Note the following:- The
serversparameter 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/post_config.yaml) that registers your heat template as the OS::TripleO::NodeExtraConfigPost: resource type.
resource_registry: OS::TripleO::NodeExtraConfigPost: /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/post_config.yaml
This applies the configuration to all nodes after the core configuration completes on either initial Overcloud creation or subsequent updates.
Important
You can only register the
OS::TripleO::NodeExtraConfigPost to only one heat template. Subsequent usage overrides the heat template to use.
