VNFD Template Parameterization

Overview

Parameterization allows for the ability to use a single VNFD to be deployed multiple times with different values for the VDU parameters provided at deploy time. In contrast, a non-parameterized VNFD has static values for the parameters that might limit the number of concurrent VNFs that can be deployed using a single VNFD. For example, deploying an instance of a non-parameterized template that has fixed IP addresses specified for network interface a second time without deleting the first instance of VNF would lead to an error.

Non-parameterized VNFD template

Find below an example of a non-parameterized VNFD where the text italicized are the VDU parameters and text in bold are the values for those VDU parameters that get applied to the VDU when this template is deployed. The next section will illustrate how the below non-parameterized template can be parameterized and re-used for deploying multiple VNFs.

template_name: cirros_user_data

description: Cirros image

service_properties:

Id: cirros

vendor: ACME

version: 1

type:

- router

- firewall

vdus:

vdu1:

id: vdu1

vm_image: cirros-0.3.4-x86_64-uec

instance_type: m1.tiny

service_type: firewall

mgmt_driver: noop

user_data: |

#!/bin/sh

echo “my hostname is `hostname`” > /tmp/hostname

df -h > /home/cirros/diskinfo

user_data_format: RAW

network_interfaces:

management:

network: net_mgmt

management: True

addresses:

- 192.168.120.11

pkt_in:

network: net0

pkt_out:

network: net1

placement_policy:

availability_zone: nova

auto-scaling: noop

monitoring_policy: noop

failure_policy: noop

config:

param0: key0

param1: key1

Parameterized VNFD template

This section will walk through parameterizing the template in above section for re-use and allow for deploying multiple VNFs with the same template. (Note: All the parameters italicized in the above template could be parameterized to accept values at deploy time). For the current illustration purpose, we will assume that an end user would want to be able to supply different values for the parameters instance_type, user_data, user_data_format and management interface IP addresses during each deploy of the VNF.

The next step is to substitute the identified parameter values that will be provided at deploy time with { get_input: <param_name>}. For example, the instance_type: m1.tiny would now be replaced as: instance_type: {get_input: flavor}. The get_input is a reserved keyword in the template that indicates value will be supplied at deploy time for the parameter instance_type. The flavor is the variable that will hold the value for the parameter instance_type in a parameters value file that will be supplied at VNF deploy time.

The template in above section will look like below when parameterized for instance_type, user_data, user_data_format and management interface IP addresses.

template_name: cirros_user_data

description: Cirros image

service_properties:

Id: cirros

vendor: ACME

version: 1

type:

- router

- firewall

vdus:

vdu1:

id: vdu1

vm_image: cirros-0.3.4-x86_64-uec

instance_type: {get_input: flavor }

service_type: firewall

mgmt_driver: noop

user_data: {get_input: user_data_value}

user_data_format: {get_input: user_data_format_value}

network_interfaces:

management:

network: net_mgmt

management: True

addresses: { get_input: mgmt_ip}

pkt_in:

network: net0

pkt_out:

network: net1

placement_policy:

availability_zone: nova

auto-scaling: noop

monitoring_policy: noop

failure_policy: noop

config:

param0: key0

param1: key1

Parameter values file at VNF deploy

The below illustrates the parameters value file to be supplied containing the values to be substituted for the above parameterized template above during VNF deploy. Note that the structure of the parameters file follows closely the structure of the VNFD template. The section below the keyword ‘param’ contains the variables and their values that will be substituted in the VNFD template. Not specifying the keyword ‘param’ as illustrated below would result in VNF failing to deploy.

vdus:

vdu1:

param:

flavor: m1.tiny

mgmt_ip:

- 192.168.120.11

user_data_format_value: RAW

user_data_value: |

#!/bin/sh echo “my hostname is hostname” > /tmp/hostname df -h > /home/cirros/diskinfo

Key Summary

• Parameterize your VNFD if you want to re-use for multiple VNF deployments.

• Identify parameters that would need to be provided values at deploy time and substitute value in VNFD template with {get_input: <param_value_name>}, where ‘param_value_name’ is the name of the variable that holds the value in the parameters value file.

• Supply a parameters value file in yaml format each time during VNF deployment with different values for the parameters.

• NOTE:IP address values for network interfaces should be in the below format in the parameters values file:

  param_name_value:

  - xxx.xxx.xxx.xxx

• An example of a vnf-create python-tackerclient command specifying a parameterized template and parameter values file would like below:

  “tacker vnf-create –vnfd-name <vnfd_name> –param-file <param_yaml_file> <vnf_name>”

• Specifying a parameter values file during VNF creation is also supported in Horizon UI.

• Sample VNFD parameterized templates and parameter values files can be found at https://github.com/openstack/tacker/tree/master/samples.