Automatic openstack resource creation based on VNFD template

Automatic openstack resource creation based on VNFD template

Creating the custom openstack resources like flavors/networks/image is one of the requirement from the VNF vendors. This blueprint proposes to add the support for automatic resource creation while onboarding the VNFD/ creating the VNF in tacker.

Problem description

With the current version of tacker, telco operators have to create the openstack resources before creating VNF. And VNF vendors cannot add the VDU details in the VNFD. For example VNF vendors cannot specify:

1)The VM details of the VDU like cpu, memory and disk etc., 2)The network details for the VDU like cidr, network_type etc., 3)The image details which is not present in glance.

Proposed Change

Introducing new host properties in VNFD template will give an initial pointer to provide the solution for the tacker. This spec will address the automatic creation of flavor, network and image.

Automatic Flavor Creation

Template Changes

           type: tosca.nodes.Compute
                       num_cpus: 2
                       disk_size: 10 GB
                       mem_size: 512 MB

When the user give host properties, Tacker will create a new flavor with those details by adding those details in heat template. Tacker will handle three minimum host properties like ‘disk_size’ and ‘num_cpus’ and ‘mem_size’. To refer the other properties, refer [1].

Tacker will fetch the properties from TOSCA template and add them to HOT as below:

heat_template_version: 2015-04-30
         type: OS::Nova::Flavor
             disk: 10
             ram: 512
             vcpus: 2

As ‘vcpus’ and ‘ram’ are required parameters in HOT, so if the template doesn’t have those details, Tacker will provide default values(vcpus=1 and ram=512).

Automatic Image Creation

Template Changes

      type: tosca.artifacts.Deployment.Image.VM
      file: http://URL/vRouterVNF.qcow2

In the modified template, users can either specify the URL for the VM image or glance image name in file type. Tacker will create the image if URL is specified in the file parameter.

In this case, we can have three options to automatically create and upload the image:

1). Specify the image URI in the template and no parameterization

If we choose this option, we can’t parameterize the vm_image. And tackers upload the image while onboarding the VNFD using glance client. It is one step process. With this option, we have to maintain the state of the VNFD based on image creation.

2). Provide the image in CSAR Zip.

Using this option, we have to ship the bundle with image needed for that VNFD. So Tacker will upload the image at onboarding time. With this option, we have to maintain the state of the VNFD based on image creation.

3). Provide parameterization and upload images at the time of VNF creation.

Here we can parameterize the vm_image attribute. With this option Tacker will upload the image into glance at VNF deployment time using HOT template.

Let’s take an example of how TOSCA image artifact can be converted to HOT image resource.


    type: tosca.artifacts.Deployment.Image.VM.qcow2
    file: http://filer/vnfimages/vrouter.qcow2


  type: OS::Glance::Image
    container_format: bare
    disk_format: qcow2
    location: http://filer/vnfimages/vrouter.qcow2

We can remove statefulness of VNFD with this option.

In this spec, we prefer the third option.

Automatic Network Creation

Template Changes

    type: tosca.nodes.nfv.VL.ELAN
    network_name: net_internal_dp
    ip_version: 4
    cidr: ''
    start_ip: ''
    end_ip: ''
    gateway_ip: ''

In this modified template, users can specify the CIDR of the network, they want to deploy VNF. If the user specify the CIDR and not the network_id, tacker will automatically create network and corresponding subnet. Refer [2] for the properties the tacker will support in network_interfaces. For the networks, tacker will create the network resources at VNF creation time using heat code. So we are not storing the network details as network resources are associated with heat stack details.

Let’s see how the above TOSCA template can be converted to HOT network resource.

        type: OS::Neutron::Net
          name: net_internal_dp

        type: OS::Neutron::Subnet
          network_id: { get_resource: private_net }
          allocation_pools: [{"end": "", "start": ""}]

Data model impact

Flavors, networks and images will be created while deploying VNF, and will be removed automatically by heat at the deletion VNF. So there won’t be any change in data model.

REST API impact


Other end user impact

User can use TOSCA templates in addition to Tacker defined templates after this spec.

Note: Auto image upload is not suitable for VNFs that would get instantiated multiple times. It will cause the same glance image to be uploaded multiple times.



Primary assignee:

  • Bharath Thiruveedula (bharath-ves)
Other contributors:

Work Items

  • Modify the calls of VNF create, so that VNF operations will be handled by plugin.




This Blueprint provides unit test cases for each of the deliverables.

Documentation Impact

devref will be modified by providing the instructions on how to adapt the new template changes.

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