VNF Descriptor Template Guide¶
Overview¶
This document explains VNFD template structure and its various fields based on TOSCA standards V1.0 CSD 03.
The behavioural and deployment information of a VNF in Tacker is defined in a template known as VNF Descriptor (VNFD). The template is based on TOSCA standards and is written in YAML. It is on-boarded in a VNF catalog.
Each VNFD template will have below fields:
tosca_definitions_version:
This defines the TOSCA definition version on which the template is based.
The current version being tosca_simple_profile_for_nfv_1_0_0.
tosca_default_namespace:
This is optional. It mentions default namespace which includes schema,
types version etc.
description:
A short description about the template.
metadata:
template_name: A name to be given to the template.
topology_template:
Describes the topology of the VNF under node_template field.
node_template:
Describes node types of a VNF.
VDU:
Describes properties and capabilities of Virtual Deployment
Unit.
CP:
Describes properties and capabilities of Connection Point.
VL:
Describes properties and capabilities of Virtual Link.
For examples, please refer sample VNFD templates available at GitHub.
Node types¶
A VNF includes VDU/s, connection point/s and virtual link/s. Hence a valid VNFD must have these 3 components. Each component is referred as a node and can have certain type, capabilities, properties, attributes and requirements. These components are described under node_templates in the VNFD template. node_templates is a child of topology_template.
VDU¶
Virtual Deployment Unit is a basic part of VNF. It is the VM that hosts the network function.
| type: | tosca.nodes.nfv.VDU.Tacker |
|---|---|
| properties: | Describes the properties like image to be used in VDU, availability zone in which VDU is to be spawned, management driver to be used to manage the VDU, flavor describing physical properties for the VDU to be spawned, monitoring policies for the VDU, providing user data in form of custom commands to the VDU. A complete list of VDU properties currently supported by Tacker are listed here under properties section of tosca.nodes.nfv.VDU.Tacker field |
Specifying VDU properties¶
A very simple VDU with 10 GB disk, 2 GB RAM, 2 CPUs, cirros image and in nova availability zone can be described as:
topology_template:
node_templates:
VDU1:
type: tosca.nodes.nfv.VDU.Tacker
properties:
image: cirros-0.3.4-x86_64-uec
availability_zone: nova
capabilities:
nfv_compute:
properties:
disk_size: 10 GB
mem_size: 2048 MB
num_cpus: 2
Using Nova flavors for VDU¶
OpenStack specific flavors can also be used to describe VDU configuration.
topology_template:
node_templates:
VDU1:
type: tosca.nodes.nfv.VDU.Tacker
properties:
image: cirros-0.3.4-x86_64-uec
flavor: m1.tiny
availability_zone: nova
However, when both nfv_compute properties and flavor are mentioned in a VNFD, flavor setting will take precedence.
Monitoring the VDU¶
A VDU can be monitored by pinging it on port 22 for 3 times at an interval of 2 seconds every 20 seconds. Number of retries be 6 and timeout of 2 seconds. It can be re-spawned in case ping fails. This is described under monitoring_policy.
..
VDU1:
type: tosca.nodes.nfv.VDU.Tacker
properties:
monitoring_policy:
name: ping
parameters:
monitoring_delay: 20
count: 3
interval: 2
timeout: 2
actions:
failure: respawn
retry: 6
port: 22
Providing user data¶
Custom commands to be run on VDU once it is spawned can be specified in a VNFD template as user data.
..
VDU1:
type: tosca.nodes.nfv.VDU.Tacker
properties:
user_data_format: RAW
user_data: |
#!/bin/sh
echo "Adding this line to demofile" > /tmp/demofile
Configuring a VDU¶
A VDU can be configured as a specific Network Function under config section in VNFD template. A sample template configuring a VDU as a firewall can be viewed in a sample file.
Specifying external image¶
| artifacts: | To specify an image via a file or an external link |
|---|
An image URL can be specified as artifacts. Tacker will specify the image location in HOT (Heat Template) and pass it to heat-api. Heat will then spawn the VDU with that image.
..
VDU1:
type: tosca.nodes.nfv.VDU.Tacker
artifacts:
VNFImage:
type: tosca.artifacts.Deployment.Image.VM
file: http://download.cirros-cloud.net/0.3.4/ \
cirros-0.3.4-x86_64-uec.tar.gz
VDU Capabilities¶
Computational properties of a VDU are described as its capabilities. Allocated RAM size, allocated disk size, memory page size, number of CPUs, number of cores per CPU, number of threads per core can be specified.
A VDU with 10 GB disk, 2 GB RAM, 2 CPUs, 4 KB of memory page and dedicated CPU can be specified as below. Thread and core counts can be specified as shown.
..
VDU1:
type: tosca.nodes.nfv.VDU.Tacker
capabilities:
nfv_compute:
properties:
disk_size: 10 GB
mem_size: 2048 MB
num_cpus: 2
mem_page_size: small
cpu_allocation:
cpu_affinity: dedicated
thread_count: 4
core_count: 2
| capabilities: |
|---|
| Name | Type | Constraints | Description |
| nfv_compute | Compute. Container. Architecture | None | Describes the configurat ion of the VM on which the VDU resides |
Compute Container Architecture¶
| type: | tosca.capabilities.Compute.Container.Architecture |
|---|---|
| properties: |
| Name | Required | Type | Constraints | Description |
mem_page_size
|
No | String | One of below
|
Indicates page size of the VM
|
| cpu_allocation | No | CPUAllo- cation | CPU allocation requirement like dedicated CPUs, socket/thread count | |
| numa_node_count | No | Integer | Symmetric count of NUMA nodes to expose to VM. vCPU and Memory is split equally across this number of NUMA | |
| numa_nodes | No | Map of NUMA | Symmetric numa_node_count should not be specified | Asymmetric allocation of vCPU and memory across the specified NUMA nodes |
CPUAllocation¶
This describes the granular CPU allocation requirements for VDUs.
| type: | tosca.datatypes.compute.Container.Architecture.CPUAllocation |
|---|---|
| properties: |
| Name | Type | Constraints | Description |
| cpu_affinity | String | One of
|
Describes whether vCPU need to be pinned to dedicated CPU core or shared dynamically |
| thread_allocation | String | One of
|
Describes thread allocation requirement |
| socket_count | Integer | None | Number of CPU sockets |
| core_count | Integer | None | Number of cores per socket |
| thread_count | Integer | None | Number of threads per core |
NUMA architecture¶
Following code snippet describes symmetric NUMA topology requirements for VDUs.
..
VDU1:
capabilities:
nfv_compute:
properties:
numa_node_count: 2
numa_nodes: 3
For asymmetric NUMA architecture:
..
VDU1:
capabilities:
nfv_compute:
properties:
mem_size: 4096 MB
num_cpus: 4
numa_nodes:
node0:
id: 0
vcpus: [0,1]
mem_size: 1024 MB
node1:
id: 1
vcpus: [2,3]
mem_size: 3072 MB
| type: | tosca.datatypes.compute.Container.Architecture.NUMA |
|---|---|
| properties: |
| Name | Type | Constraints | Description |
| id | Integer | >= 0 | CPU socket identifier |
| vcpus | Map of integers | None | List of specific host cpu numbers within a NUMA socket complex |
| mem_size | scalar- unit.size | >= 0MB | Size of memory allocated from this NUMA memory bank |
Connection Points¶
Connection point is used to connect the internal virtual link or outside virtual link. It may be a virtual NIC or a SR-IOV NIC. Each connection point has to bind to a VDU. A CP always requires a virtual link and a virtual binding associated with it.
A code snippet for virtual NIC (Connection Point) without anti-spoof protection and are accessible by the user. CP1 and CP2 are connected to VDU1 in this order. Also CP1/CP2 are connected to VL1/VL2 respectively.
..
topology_template:
node_templates:
VDU1:
..
CP1:
type: tosca.nodes.nfv.CP.Tacker
properties:
mac_address: fa:40:08:a0:de:0a
ip_address: 10.10.1.12
type: vnic
anti_spoofing_protection: false
management: true
order: 0
security_groups:
- secgroup1
- secgroup2
requirements:
- virtualLink:
node: VL1
- virtualBinding:
node: VDU1
CP2:
type: tosca.nodes.nfv.CP.Tacker
properties:
type: vnic
anti_spoofing_protection: false
management: true
order: 1
requirements:
- virtualLink:
node: VL2
- virtualBinding:
node: VDU1
VL1:
..
VL2:
..
| type: | tosca.nodes.nfv.CP.Tacker |
|---|---|
| properties: |
| Name | Required | Type | Constraints | Description |
| type | No | String | One of
|
Specifies the type of CP |
| anti_spoofing_protection | No | Boolean | None | Indicates whether anti_spoof rule is enabled for the VNF or not. Applicable only when CP type is virtual NIC |
| management | No | Boolean | None | Specifies whether the CP is accessible by the user or not |
| order | No | Integer | >= 0 | Uniquely numbered order of CP within a VDU. Must be provided when binding more than one CP to a VDU and ordering is required. |
| security_groups | No | List | None | List of security groups to be associated with the CP |
| mac_address | No | String | None | The MAC address |
| ip _address | No | String | None | The IP address |
| requirements: |
|---|
| Name | Capability | Relationship | Description |
| virtualLink | nfv.VirtualLinkable | nfv.VirtualLinksTo | States the VL node to connect to |
| virtualbinding | nfv.VirtualBindable | nfv.VirtualBindsTo | States the VDU node to connect to |
Virtual Links¶
Virtual link provides connectivity between VDUs. It represents the logical virtual link entity.
An example of a virtual link whose vendor is Acme and is attached to network net-01 is as shown below.
..
topology_template:
node_templates:
VDU1:
..
CP1:
..
VL1:
type: tosca.nodes.nfv.VL
properties:
vendor: Acme
network_name: net-01
| type: | tosca.nodes.nfv.VL |
|---|---|
| properties: |
| Name | Required | Type | Constraints | Description |
| vendor | Yes | String | None | Vendor generating this VL |
| network_name | Yes | String | None | Name of the network to which VL is to be attached |
Multiple nodes¶
Multiple node types can be defined in a VNFD.
..
topology_template:
node_templates:
VDU1:
..
VDU2:
..
CP1:
..
CP2:
..
VL1:
..
VL2:
..
Summary¶
To summarize VNFD is written in YAML and describes a VNF topology. It has three node types, each with different capabilities and requirements. Below is a template which mentions all node types with all available options.
tosca_definitions_version: tosca_simple_profile_for_nfv_1_0_0
description: Sample VNFD template mentioning possible values for each node.
metadata:
template_name: sample-tosca-vnfd-template-guide
topology_template:
node_templates:
VDU:
type: tosca.nodes.nfv.VDU.Tacker
capabilities:
nfv_compute:
properties:
mem_page_size: [small, large, any, custom]
cpu_allocation:
cpu_affinity: [shared, dedicated]
thread_allocation: [avoid, separate, isolate, prefer]
socket_count: any integer
core_count: any integer
thread_count: any integer
numa_node_count: any integer
numa_nodes:
node0: [ id: >=0, vcpus: [host CPU numbers], mem_size: >= 0MB]
properties:
image: Image to be used in VM
flavor: Nova supported flavors
availability_zone: available availability zone
mem_size: in MB
disk_size: in GB
num_cpus: any integer
metadata:
entry_schema:
config_drive: [true, false]
monitoring_policy:
name: [ping, noop, http-ping]
parameters:
monitoring_delay: delay time
count: any integer
interval: time to wait between monitoring
timeout: monitoring timeout time
actions:
[failure: respawn, failure: terminate, failure: log]
retry: Number of retries
port: specific port number if any
config: Configuring the VDU as per the network function requirements
mgmt_driver: [default=noop]
service_type: type of network service to be done by VDU
user_data: custom commands to be executed on VDU
user_data_format: format of the commands
key_name: user key
artifacts:
VNFImage:
type: tosca.artifacts.Deployment.Image.VM
file: file to be used for image
CP:
type: tosca.nodes.nfv.CP.Tacker
properties:
management: [true, false]
anti_spoofing_protection: [true, false]
type: [ sriov, vnic ]
order: order of CP within a VDU
security_groups: list of security groups
requirements:
- virtualLink:
node: VL to link to
- virtualBinding:
node: VDU to bind to
VL:
type: tosca.nodes.nfv.VL
properties:
network_name: name of network to attach to
vendor: Acme