Openstack Vendordata

To read more about Openstack Vendordata see upstream docs

Overview

It is a feature that provides way to pass vendor-specific data to the instances at boot-time. It can be accessed with one of the following ways:

Also, Vendordata sources can be specified with two ways:

StaticJSON collects data from a JSON file that exits locally and is suitable when data remains same for all instances. On the other hand DynamicJSON can collect data from external REST service and works well when that data does change for instances.

Vendordata in genestack

Genestack use Metadata Service to access Vendordata. It has StaticJSON enabled in nova.conf as default provider:

api:
  vendordata_providers: ['StaticJSON']
  vendordata_jsonfile_path: /etc/nova/vendor_data.json

You can override the default configmap /opt/genestack/base-kustomize/nova/base/static-vendordata-configmap to pass static vendor-data against vendor_data.json key, which is mounted at /etc/nova/vendor_data.json in metadata service resources.

For DynamicJSON you need to enable it amongst providers and have to specify dynamic target URL(s) in nova.conf as follows:

api:
  vendordata_providers: ['StaticJSON', 'DynamicJSON']
  vendordata_jsonfile_path: /etc/nova/vendor_data.json
  vendordata_dynamic_targets: ['target/url1', 'target/url2']

A POST request call will be made to these dynamic targets and you can expect the request body contains instance's context e.g. instance-id, image-id, hostname etc. These targets should return a valid JSON in response.

Cloud-init and Vendordata

Cloud-init instructions can be passed-in as string against key - cloud-init within Vendordata JSON as follows:

{
  "cloud-init": "#cloud-config\nruncmd:\n..."
}

See cloud-init docs for more details.