Homing Specification Guide

This document describes the Homing Template format, used by the Homing service. It is a work in progress and subject to frequent revision.

Template Structure

Homing templates are defined in YAML and follow the structure outlined below.

homing_template_version: 2017-10-10
parameters:
  PARAMETER_DICT
locations:
  LOCATION_DICT
demands:
  DEMAND_DICT
constraints:
  CONSTRAINT_DICT
reservations:
  RESERVATION_DICT
optimization:
  OPTIMIZATION
  • homing_template_version: This key with value 2017-10-10 (or a later date) indicates that the YAML document is a Homing template of the specified version.

  • parameters: This section allows for specifying input parameters that have to be provided when instantiating the homing template. Typically, this section is used for providing runtime parameters (like SLA thresholds), which in turn is used in the existing homing policies. The section is optional and can be omitted when no input is required.

  • locations: This section contains the declaration of geographic locations. This section is optional and can be omitted when no input is required.

  • demands: This section contains the declaration of demands. This section with at least one demand should be defined in any Homing template, or the template would not really do anything when being instantiated.

  • constraints: This section contains the declaration of constraints. The section is optional and can be omitted when no input is required.

  • reservations: This section contains the declaration of required reservations. This section is optional and can be omitted when reservations are not required.

  • optimization: This section allows the declaration of an optimization. This section is optional and can be omitted when no input is required.

Homing Template Version

The value of homing_template_version tells HAS not only the format of the template but also features that will be validated and supported. Only one value is supported: 2017-10-10 in the initial release of HAS.

homing_template_version: 2017-10-10

Parameters

The parameters section allows for specifying input parameters that have to be provided when instantiating the template. Such parameters are typically used for providing runtime inputs (like SLA thresholds), which in turn is used in the existing homing policies. This also helps build reusable homing constraints where these parameters can be embedded design time, and it corresponding values can be supplied during runtime.

Each parameter is specified with the name followed by its value. Values can be strings, lists, or dictionaries.

Example

In this example, provider_name is a string and service_info is a dictionary containing both a string and a list (keyed by base_url and nod_config, respectively).

parameters:
  provider_name: multicloud
  service_info:
    base_url: http://serviceprovider.sdngc.com/
    nod_config:
    - http://nod/config_a.yaml
    - http://nod/config_b.yaml
    - http://nod/config_c.yaml
    - http://nod/config_d.yaml

A parameter can be referenced in place of any value. See the Intrinsic Functions section for more details.

Locations

One or more locations may be declared. A location may be referenced by one or more constraints. Locations may be defined in any of the following ways:

Coordinate

A geographic coordinate expressed as a latitude and longitude.

Key

Value

latitude

Latitude of the location.

longitude

Longitude of the location.

Host Name

An opaque host name that can be translated to a coordinate via an inventory provider (e.g., A&AI).

Key

Value

host_name

Host name identifying a location.

CLLI

Common Language Location Identification (CLLI) code(https://en.wikipedia.org/wiki/CLLI_code).

Key

Value

clli_code

8 character CLLI.

Questions

  • Do we need functions that can convert one of these to the other? E.g., CLLI Codes to a latitude/longitude

Placemark

An address expressed in geographic region-agnostic terms (referred to as a placemark).

*This is an example as of Frankfurt release. Support for this schema is

deferred to subsequent release.*

Key

Value

iso_country_code

The abbreviated country name associated with the placemark.

postal_code

The postal code associated with the placemark.

administrative_area

The state or province associated with the placemark.

sub_administrative_area

Additional administrative area information for the placemark.

locality

The city associated with the placemark.

sub_locality

Additional city-level information for the placemark.

thoroughfare

The street address associated with the placemark.

sub_thoroughfare

Additional street-level information for the placemark.

Note:

  • A geocoder could be used to convert placemarks to a latitude/longitude

Examples

The following examples illustrate a location expressed in coordinate, host_name, CLLI, and placemark, respectively.

locations:
  location_using_coordinates:
    latitude: 32.897480
    longitude: -97.040443

  host_location_using_host_name:
    host_name: USESTCDLLSTX55ANZ123

  location_using_clli:
    clli_code: DLLSTX55

  location_using_placemark:
    sub_thoroughfare: 1
    thoroughfare: ATT Way
    locality: Bedminster
    administrative_area: NJ
    postal_code: 07921-2694

Demands

A demand can be satisfied by using candidates drawn from inventories. Each demand is uniquely named. Inventory is considered to be opaque and can represent anything from which candidates can be drawn.

A demand’s resource requirements are determined by asking an inventory provider for one or more sets of inventory candidates against which the demand will be made. An explicit set of candidates may also be declared, for example, if the only candidates for a demand are predetermined.

Demand criteria is dependent upon the inventory provider in use.

Provider-agnostic Schema

Key

Value

inventory_provider

A HAS-supported inventory provider.

inventory_type

The reserved words cloud (cloud regions), service (for existing service instances), vfmodule (for vf instances), nssi (for slice subnet instances), nst (for slice templates). Exactly one inventory type may be specified.

filtering_attributes (Optional)

A list of key-value pairs, that is used to select inventory candidates that match all the specified attributes. The key should be a uniquely identifiable attribute at the inventory provider.

passthrough_attributes (Optional)

A list of key-value pairs, that will be added to the candidate’s attribute directly from template.

service_type (Optional)

If inventory_type is service, a list of one or more provider-defined service types. If only one service type is specified, it may appear without list markers ([]).

service_id (Optional)

If inventory_type is service, a list of one or more provider-defined service ids. If only one service id is specified, it may appear without list markers ([]).

default_cost (Optional)

The default cost of an inventory candidate, expressed as currency. This must be specified if the inventory provider may not always return a cost.

required_candidates (Optional)

A list of one or more candidates from which a solution will be explored. Must be a valid candidate as described in the candidate schema.

excluded_candidates (Optional)

A list of one or more candidates that should be excluded from the search space. Must be a valid candidate as described in the candidate schema.

existing_placement (Optional)

The current placement for the demand. Must be a valid candidate as described in the candidate schema.

Note

  • The demand attributes in the template come from either policy or from a northbound request scope.

Examples

The following example helps understand a demand specification using Active & Available Inventory (A&AI), the inventory provider-of-record for ONAP.

Inventory Provider Criteria

Key

Value

inventory_provider

Examples: aai, multicloud.

inventory_type

The reserved words cloud (cloud regions), service (for existing service instances), vfmodule (for vf instances), nssi (for slice subnet instances), nst (for slice templates). Exactly one inventory type may be specified.

filtering attributes

(Optional)

A list of key-value pairs to match against inventory when drawing candidates.

passthrough_attributes (Optional)

A list of key-value pairs, that will be added to the candidate’s attribute directly from template.

service_type (Optional)

Examples may include vG, vG_MuxInfra, etc.

service_id (Optional)

Must be a valid service id. Examples may include vCPE, VoLTE, etc.

default_cost (Optional)

The default cost of an inventory candidate, expressed as a unitless number.

required_candidates (Optional)

A list of one or more valid candidates. See Candidate Schema for details.

excluded_candidates (Optional)

A list of one or more valid candidates. See Candidate Schema for details.

existing_placement (Optional)

A single valid candidate, representing the current placement for the demand. See candidate schema for details.

Candidate Schema

The following is the schema for a valid candidate:

  • candidate_id uniquely identifies a candidate. Currently, it is either a Service Instance ID or Cloud Region ID.

  • candidate_type identifies the type of the candidate. Currently, it is either cloud or service. * inventory_type is defined as described in Inventory Provider Criteria (above).

  • inventory_provider identifies the inventory from which the candidate was drawn. *

  • host_id is an ID of a specific host (used only when referring to service/existing inventory).

  • cost is expressed as a unitless number.

  • location_id is always a location ID of the specified location type (e.g., for a type of cloud this will be an Cloud Region ID).

  • location_type is an inventory provider supported location type.

  • latitude is a valid latitude corresponding to the location_id.

  • longitude is a valid longitude corresponding to the location_id.

  • city (Optional) city corresponding to the location_id.

  • state (Optional) state corresponding to the location_id.

  • country (Optional) country corresponding to the location_id.

  • region (Optional) geographic region corresponding to the location_id.

  • complex_name (Optional) Name of the complex corresponding to the location_id.

  • cloud_owner (Optional) refers to the cloud owner (e.g., azure, aws, att, etc.).

  • cloud_region_version (Optional) is an inventory provider supported version of the cloud region.

  • physical_location_id (Optional) is an inventory provider supported CLLI code corresponding to the cloud region.

Examples

Service Candidate

{
    "candidate_id": "1ac71fb8-ad43-4e16-9459-c3f372b8236d",
    "candidate_type": "service",
    "inventory_type": "service",
    "inventory_provider": "aai",
    "host_id": "vnf_123456",
    "cost": "100",
    "location_id": "DLLSTX9A",
    "location_type": "azure",
    "latitude": "32.897480",
    "longitude": "-97.040443",
    "city": "Dallas",
    "state": "TX",
    "country": "USA",
    "region": "US",
    "complex_name": "dalls_one",
    "cloud_owner": "att-aic",
    "cloud_region_version": "1.1",
    "physical_location_id": "DLLSTX9A"
}

Cloud Candidate

{
    "candidate_id": "NYCNY55",
    "candidate_type": "cloud",
    "inventory_type": "cloud",
    "inventory_provider": "aai",
    "cost": "100",
    "location_id": "NYCNY55",
    "location_type": "azure",
    "latitude": "40.7128",
    "longitude": "-74.0060",
    "city": "New York",
    "state": "NY",
    "country": "USA",
    "region": "US",
    "complex_name": "ny_one",
    "cloud_owner": "att-aic",
    "cloud_region_version": "1.1",
    "physical_location_id": "NYCNY55",
    "flavors": {
       "flavor":[
          {
             "flavor-id":"9cf8220b-4d96-4c30-a426-2e9382f3fff2",
             "flavor-name":"flavor-numa-cpu-topology-instruction-set",
             "flavor-vcpus":64,
             "flavor-ram":65536,
             "flavor-disk":1048576,
             "flavor-ephemeral":128,
             "flavor-swap":"0",
             "flavor-is-public":false,
             "flavor-selflink":"pXtX",
             "flavor-disabled":false,
             "hpa-capabilities":{
                "hpa-capability":[
                   {
                      "hpa-capability-id":"01a4bfe1-1993-4fda-bd1c-ef333b4f76a9",
                      "hpa-feature":"cpuInstructionSetExtensions",
                      "hpa-version":"v1",
                      "architecture":"Intel64",
                      "resource-version":"1521306560982",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"instructionSetExtensions",
                            "hpa-attribute-value":"{\"value\":{['AAA', 'BBB', 'CCC', 'DDD']}}",
                            "resource-version":"1521306560989"
                         }
                      ]
                   },
                   {
                      "hpa-capability-id":"167ad6a2-7d9c-4bf2-9a1b-30e5311b8c66",
                      "hpa-feature":"numa",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306561020",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"numaCpu-1",
                            "hpa-attribute-value":"{\"value\":4}",
                            "resource-version":"1521306561060"
                         },
                         {
                            "hpa-attribute-key":"numaNodes",
                            "hpa-attribute-value":"{\"value\":2}",
                            "resource-version":"1521306561088"
                         },
                         {
                            "hpa-attribute-key":"numaCpu-0",
                            "hpa-attribute-value":"{\"value\":2}",
                            "resource-version":"1521306561028"
                         },
                         {
                            "hpa-attribute-key":"numaMem-0",
                            "hpa-attribute-value":"{\"value\":2, \"unit\":\"GB\" }",
                            "resource-version":"1521306561044"
                         },
                         {
                            "hpa-attribute-key":"numaMem-1",
                            "hpa-attribute-value":"{\"value\":4, \"unit\":\"GB\" }",
                            "resource-version":"1521306561074"
                         }
                      ]
                   },
                   {
                      "hpa-capability-id":"13ec6d4d-7fee-48d8-9e4a-c598feb101ed",
                      "hpa-feature":"basicCapabilities",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306560909",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"numVirtualCpu",
                            "hpa-attribute-value":"{\"value\":64}",
                            "resource-version":"1521306560932"
                         },
                         {
                            "hpa-attribute-key":"virtualMemSize",
                            "hpa-attribute-value":"{\"value\":65536, \"unit\":\"MB\" }",
                            "resource-version":"1521306560954"
                         }
                      ]
                   },
                   {
                      "hpa-capability-id":"8fa22e64-41b4-471f-96ad-6c4708635e4c",
                      "hpa-feature":"cpuTopology",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306561109",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"numCpuCores",
                            "hpa-attribute-value":"{\"value\":8}",
                            "resource-version":"1521306561114"
                         },
                         {
                            "hpa-attribute-key":"numCpuThreads",
                            "hpa-attribute-value":"{\"value\":8}",
                            "resource-version":"1521306561138"
                         },
                         {
                            "hpa-attribute-key":"numCpuSockets",
                            "hpa-attribute-value":"{\"value\":6}",
                            "resource-version":"1521306561126"
                         }
                      ]
                   }
                ]
             },
             "resource-version":"1521306560203"
          },
          {
             "flavor-id":"f5aa2b2e-3206-41b6-80d5-cf041b098c43",
             "flavor-name":"flavor-cpu-pinning-ovsdpdk-instruction-set",
             "flavor-vcpus":32,
             "flavor-ram":131072,
             "flavor-disk":2097152,
             "flavor-ephemeral":128,
             "flavor-swap":"0",
             "flavor-is-public":false,
             "flavor-selflink":"pXtX",
             "flavor-disabled":false,
             "hpa-capabilities":{
                "hpa-capability":[
                   {
                      "hpa-capability-id":"4d04f4d8-e257-4442-8417-19a525e56096",
                      "hpa-feature":"cpuInstructionSetExtensions",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306561223",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"instructionSetExtensions",
                            "hpa-attribute-value":"{\"value\":{['A11', 'B22']}}",
                            "resource-version":"1521306561228"
                         }
                      ]
                   },
                   {
                      "hpa-capability-id":"8d36a8fe-bfee-446a-bbcb-881ee66c8f78",
                      "hpa-feature":"ovsDpdk",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306561170",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"dataProcessingAccelerationLibrary",
                            "hpa-attribute-value":"{\"value\":\"v18.02\"}",
                            "resource-version":"1521306561175"
                         }
                      ]
                   },
                   {
                      "hpa-capability-id":"c140c945-1532-4908-86c9-d7f71416f1dd",
                      "hpa-feature":"cpuPinning",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306561191",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"logicalCpuPinningPolicy",
                            "hpa-attribute-value":"{\"value\":\"dedicated\"}",
                            "resource-version":"1521306561196"
                         },
                         {
                            "hpa-attribute-key":"logicalCpuThreadPinningPolicy",
                            "hpa-attribute-value":"{value:\"prefer\"}",
                            "resource-version":"1521306561206"
                         }
                      ]
                   },
                   {
                      "hpa-capability-id":"4565615b-1077-4bb5-a340-c5be48db2aaa",
                      "hpa-feature":"basicCapabilities",
                      "hpa-version":"v1",
                      "architecture":"generic",
                      "resource-version":"1521306561244",
                      "hpa-feature-attributes":[
                         {
                            "hpa-attribute-key":"numVirtualCpu",
                            "hpa-attribute-value":"{\"value\":32}",
                            "resource-version":"1521306561259"
                         },
                         {
                            "hpa-attribute-key":"virtualMemSize",
                            "hpa-attribute-value":"{\"value\":131072, \"unit\":\"MB\" }",
                            "resource-version":"1521306561248"
                         }
                      ]
                   }
                ]
             },
             "resource-version":"1521306561164"
          }
       ]
    }
}

vfmodule candidate

{
    "candidate_id": "d187d743-5932-4fb9-a42d-db0a5be5ba7e",
    "city": "example-city-val-27150",
    "cloud_owner": "CloudOwner",
    "cloud_region_version": "1",
    "complex_name": "clli1",
    "cost": 1.0,
    "country": "example-country-val-94173",
    "existing_placement": "false",
    "host_id": "vFW-PKG-MC",
    "inventory_provider": "aai",
    "inventory_type": "vfmodule",
    "ipv4-oam-address": "oam_network_zb4J",
    "ipv6-oam-address": "",
    "latitude": "example-latitude-val-89101",
    "location_id": "RegionOne",
    "location_type": "att_aic",
    "longitude": "32.89948",
    "nf-id": "fcbff633-47cc-4f38-a98d-4ba8285bd8b6",
    "nf-name": "vFW-PKG-MC",
    "nf-type": "vnf",
    "passthrough_attributes": {
        "td-role": "anchor"
    },
    "physical_location_id": "clli1",
    "port_key": "vlan_port",
    "region": "example-region-val-13893",
    "service_instance_id": "3e8d118c-10ca-4b4b-b3db-089b5e9e6a1c",
    "service_resource_id": "vPGN-XX",
    "sriov_automation": "false",
    "state": "example-state-val-59487",
    "uniqueness": "false",
    "vf-module-id": "d187d743-5932-4fb9-a42d-db0a5be5ba7e",
    "vf-module-name": "vnf-pkg-r1-t2-mc",
    "vim-id": "CloudOwner_RegionOne",
    "vlan_key": "vlan_key",
    "vnf-type": "5G_EVE_Demo/5G_EVE_PKG 0",
    "vservers": [
        {
            "l-interfaces": [
                {
                    "interface-id": "4b333af1-90d6-42ae-8389-d440e6ff0e93",
                    "interface-name": "vnf-pkg-r1-t2-mc-vpg_private_2_port-mf7lu55usq7i",
                    "ipv4-addresses": [
                        "10.100.100.2"
                    ],
                    "ipv6-addresses": [],
                    "macaddr": "fa:16:3e:c4:07:7f",
                    "network-id": "59763a33-3296-4dc8-9ee6-2bdcd63322fc",
                    "network-name": ""
                },
                {
                    "interface-id": "85dd57e9-6e3a-48d0-a784-4598d627e798",
                    "interface-name": "vnf-pkg-r1-t2-mc-vpg_private_1_port-734xxixicw6r",
                    "ipv4-addresses": [
                        "10.0.110.2"
                    ],
                    "ipv6-addresses": [],
                    "macaddr": "fa:16:3e:b5:86:38",
                    "network-id": "cdb4bc25-2412-4b77-bbd5-791a02f8776d",
                    "network-name": ""
                },
                {
                    "interface-id": "edaff25a-878e-4706-ad52-4e3d51cf6a82",
                    "interface-name": "vnf-pkg-r1-t2-mc-vpg_private_0_port-e5qdm3p5ijhe",
                    "ipv4-addresses": [
                        "192.168.10.200"
                    ],
                    "ipv6-addresses": [],
                    "macaddr": "fa:16:3e:ff:d8:6f",
                    "network-id": "932ac514-639a-45b2-b1a3-4c5bb708b5c1",
                    "network-name": ""
                }
            ],
            "vserver-id": "00bddefc-126e-4e4f-a18d-99b94d8d9a30",
            "vserver-name": "zdfw1fwl01pgn01"
        }
    ]
}

nssi candidate

{
    "candidate_id": "1a636c4d-5e76-427e-bfd6-241a947224b0",
    "candidate_type": "nssi",
    "conn_density": 0,
    "cost": 1.0,
    "domain": "cn",
    "e2e_latency": 0,
    "exp_data_rate": 0,
    "exp_data_rate_dl": 100,
    "exp_data_rate_ul": 100,
    "instance_name": "nssi_test_0211",
    "inventory_provider": "aai",
    "inventory_type": "nssi",
    "jitter": 0,
    "latency": 20,
    "max_number_of_ues": 0,
    "nsi_id": "4115d3c8-dd59-45d6-b09d-e756dee9b518",
    "nsi_model_invariant_id": "39b10fe6-efcc-40bc-8184-c38414b80771",
    "nsi_model_version_id": "8b664b11-6646-4776-9f59-5c3de46da2d6",
    "nsi_name": "nsi_test_0211",
    "payload_size": 0,
    "reliability": 99.99,
    "resource_sharing_level": "0",
    "survival_time": 0,
    "traffic_density": 0,
    "ue_mobility_level": "stationary",
    "uniqueness": "true"
}

Examples

The following examples illustrate two demands:

  • vGMuxInfra: A vGMuxInfra service, drawing candidates of type service from the inventory. Only candidates that match the customer_id and orchestration-status will be included in the search space.

  • vG: A vG, drawing candidates of type service and cloud from the inventory. Only candidates that match the customer_id and provisioning-status will be included in the search space.

demands:
  vGMuxInfra:
  - inventory_provider: aai
    inventory_type: service
    attributes:
      equipment_type: vG_Mux
      customer_id: some_company
      orchestration-status: Activated
      model-id: 174e371e-f514-4913-a93d-ed7e7f8fbdca
      model-version: 2.0
  vG:
  - inventory_provider: aai
    inventory_type: service
    attributes:
      equipment_type: vG
      customer_id: some_company
      provisioning-status: provisioned
  - inventory_provider: aai
    inventory_type: cloud

Note

  • Cost could be used to specify the cost of choosing a specific candidate. For example, choosing an existing VNF instance can be less costlier than creating a new instance.

Constraints

A Constraint is used to eliminate inventory candidates from one or more demands that do not meet the requirements specified by the constraint. Since reusability is one of the cornerstones of HAS, Constraints are designed to be service-agnostic, and is parameterized such that it can be reused across a wide range of services. Further, HAS is designed with a plug-in architecture that facilitates easy addition of new constraint types.

Constraints are denoted by a constraints key. Each constraint is uniquely named and set to a dictionary containing a constraint type, a list of demands to apply the constraint to, and a dictionary of constraint properties.

Considerations while using multiple constraints * Constraints should be treated as a unordered list, and no assumptions should be made as regards to the order in which the constraints are evaluated for any given demand. * All constraints are effectively AND-ed together. Constructs such as “Constraint X OR Y” are unsupported. * Constraints are reducing in nature, and does not increase the available candidates at any point during the constraint evaluations.

Schema

Key

Value

CONSTRAINT_NAME

Key is a unique name.

type

The type of constraint. See Constraint Types for a list of currently supported values.

demands

One or more previously declared demands. If only one demand is specified, it may appear without list markers ([]).

properties (Optional)

Properties particular to the specified constraint type. Use if required by the constraint.

constraints:
  CONSTRAINT_NAME_1:
    type: CONSTRAINT_TYPE
    demands: DEMAND_NAME | [DEMAND_NAME_1, DEMAND_NAME_2, ...]
    properties: PROPERTY_DICT

  CONSTRAINT_NAME_2:
    type: CONSTRAINT_TYPE
    demands: DEMAND_NAME | [DEMAND_NAME_1, DEMAND_NAME_2, ...]
    properties: PROPERTY_DICT

  ...

Constraint Types

Type

Description

attribute

Constraint that matches the specified list of Attributes.

distance_between_demands

Geographic distance constraint between each pair of a list of demands.

distance_to_location

Geographic distance constraint between each of a list of demands and a specific location.

instance_fit

Constraint that ensures available capacity in an existing service instance for an incoming demand.

inventory_group

Constraint that enforces two or more demands are satisfied using candidates from a pre-established group in the inventory.

region_fit

Constraint that ensures available capacity in an existing cloud region for an incoming demand.

zone

Constraint that enforces co-location/diversity at the granularities of clouds/regions/availabil ity-zones.

hpa

Constraint that recommends cloud region with an optimal flavor based on required HPA capabilities for an incoming demand.

vim_fit

Constraint that checks if the incoming demand fits the VIM instance.

license (Deferred)

License availability constraint.

network_between_demands (Deferred)

Network constraint between each pair of a list of demands.

network_to_location (Deferred)

Network constraint between each of a list of demands and a specific location/address.

threshold

Constraint that checks if an attribute is within the threshold.

Note: Constraint names marked “Deferred” **will not* be supported in the current release of HAS.*

Threshold Values

Constraint property values representing a threshold may be an integer or floating point number, optionally prefixed with a comparison operator: =, <, >, <=, or >=. The default is = and optionally suffixed with a unit.

Whitespace may appear between the comparison operator and value, and between the value and units. When a range values is specified (e.g., 10-20 km), the comparison operator is omitted.

Each property is documented with a default unit. The following units are supported:

Unit

Values

Default

Currency

USD

USD

Time

ms, sec

ms

Distance

km, mi

km

Throughput

Kbps, Mbps, Gbps

Mbps

Attribute

Constrain one or more demands by one or more attributes, expressed as properties. Attributes are mapped to the inventory provider specified properties, referenced by the demands. For example, properties could be hardware capabilities provided by the platform (flavor, CPU-Pinning, NUMA), features supported by the services, etc.

Schema

Property

Value

evaluate

Opaque dictionary of attribute name and value pairs. Values must be strings or numbers. Encoded and sent to the service provider via a plugin.

Note: Attribute values are not detected/parsed as thresholds by the Homing framework. Such interpretations and evaluations are inventory provider-specific and delegated to the corresponding plugin

constraints:
  sriov_nj:
    type: attribute
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      evaluate:
        cloud_version: 1.1
        flavor: SRIOV
        subdivision: US-TX
        vcpu_pinning: True
        numa_topology: numa_spanning

Proposal: Evaluation Operators

To assist in evaluating attributes, the following operators and notation are proposed:

Operator

Name

Operand

eq

==

Any object (string, number, list, dict)

ne

!=

lt

<

A number (strings are converted to float)

gt

>

lte

<=

gte

>=

any

Any

A list of objects (string, number, list, dict)

all

All

regex

RegEx

A regular expression pattern

Example usage:

constraints:
  sriov_nj:
    type: attribute
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      evaluate:
        cloud_version: {gt: 1.0}
        flavor: {regex: /^SRIOV$/i}
        subdivision: {any: [US-TX, US-NY, US-CA]}

Distance Between Demands

Constrain each pairwise combination of two or more demands by distance requirements.

Schema

Name

Value

distance

Distance between demands, measured by the geographic path.

The constraint is applied between each pairwise combination of demands. For this reason, at least two demands must be specified, implicitly or explicitly.

constraints:
  distance_vnf1_vnf2:
    type: distance_between_demands
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      distance: < 250 km

Distance To Location

Constrain one or more demands by distance requirements relative to a specific location.

Schema

Property

Value

distance

Distance between demands, measured by the geographic path.

location

A previously declared location.

The constraint is applied between each demand and the referenced location, not across all pairwise combinations of Demands.

constraints:
  distance_vnf1_loc:
    type: distance_to_location
    demands: [my_vnf_demand, my_other_vnf_demand, another_vnf_demand]
    properties:
      distance: < 250 km
      location: LOCATION_ID

Instance Fit

Constrain each demand by its service requirements.

Requirements are sent as a request to a service controller. Service controllers are defined by plugins in Homing (e.g., sdn-c).

A service controller plugin knows how to communicate with a particular endpoint (via HTTP/REST, DMaaP, etc.), obtain necessary information, and make a decision. The endpoint and credentials can be configured through plugin settings.

Schema

Property

Description

controller

Name of a service controller.

request

Opaque dictionary of key/value pairs. Values must be strings or numbers. Encoded and sent to the service provider via a plugin.

constraints:
  check_for_availability:
    type: instance_fit
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      controller: sdn-c
      request: REQUEST_DICT

Region Fit

Constrain each demand’s inventory candidates based on inventory provider membership.

Requirements are sent as a request to a service controller. Service controllers are defined by plugins in Homing (e.g., sdn-c).

A service controller plugin knows how to communicate with a particular endpoint (via HTTP/REST, DMaaP, etc.), obtain necessary information, and make a decision. The endpoint and credentials can be configured through plugin settings.

Schema

Property

Description

controller

Name of a service controller.

request

Opaque dictionary of key/value pairs. Values must be strings or numbers. Encoded and sent to the service provider via a plugin.

constraints:
  check_for_membership:
    type: region_fit
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      controller: sdn-c
      request: REQUEST_DICT

Zone

Constrain two or more demands such that each is located in the same or different zone category.

Zone categories are inventory provider-defined, based on the demands being constrained.

Schema

Property

Value

qualifier

Zone qualifier. One of same or different.

category

Zone category. One of disaster, region, complex, time, or maintenance.

For example, to place two demands in different disaster zones:

constraints:
  vnf_diversity:
    type: zone
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      qualifier: different
      category: disaster

Or, to place two demands in the same region:

constraints:
  vnf_affinity:
    type: zone
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      qualifier: same
      category: region

Notes

  • These categories could be any of the following: disaster_zone, region, complex, time_zone, and maintenance_zone. Really, we are talking affinity/anti-affinity at the level of DCs, but these terms may cause confusion with affinity/anti-affinity in OpenStack.

HPA & Cloud Agnostic Intent

Constrain each demand’s inventory candidates based on cloud regions’ Hardware platform capabilities (HPA) and also intent support. Note that currently HPA the cloud agnostic constraints will use the same schema.

Requirements mapped to the inventory provider specified properties, referenced by the demands. For eg, properties could be hardware capabilities provided by the platform through flavors or cloud-region eg:(CPU-Pinning, NUMA), features supported by the services, etc.

Schema

Property

Value

evaluate

List of id, type, directives and flavorProperties of each VM of the VNF demand.

Property for evaluation

Value

id

Name of VFC

type

Type of VFC. Could be vnfc or tocsa.nodes.nfv. Vdu.Compute according to different models

directives

Directives for one VFC. Now we only have flavor directives inside. Each VFC must have one directive

flavorProperties

Flavor properties for one VFC. Contains detailed HPA requirements

Property for directives

Value

type

Type of directive

attributes

Attributes inside directive

Property for attributes

Value

attribute_name

Attribute name/label

attributes_value

Attributes value

Note: Each VFC must have one directive with type ‘flavor_directives’ to put the flavors inside. The attribute_name is the place to put flavor label and the attribute_value will first left blank. After getting the proper flavor, OOF will merge the flavor name into the attribute_value inside flavor directives. Also, all the directives coming from one VFC inside the same request will be merged together in directives, as they are using the same structure as ‘directives’.

constraints:
  hpa_constraint:
    type: hpa
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      evaluate:
        - [ List of {id: {vdu Name},
                    type: {type of VF },
                    directives: DIRECTIVES LIST,
                    flavorProperties: HPACapability DICT} ]

HPACapability DICT :
  hpa-feature: basicCapabilities
  hpa-version: v1
  architecture: generic
  directives:
    - DIRECTIVES LIST
  hpa-feature-attributes:
    - HPAFEATUREATTRIBUTES LIST

DIRECTIVES LIST:
  type: String
  attributes:
    - ATTRIBUTES LIST

ATTRIBUTES LIST:
  attribute_name: String,
  attribute_value: String

HPAFEATUREATTRIBUTES LIST:
  hpa-attribute-key: String
  hpa-attribute-value: String
  operator: One of OPERATOR
  unit: String
OPERATOR : ['=', '<', '>', '<=', '>=', 'ALL']

Example

Example for HEAT request(SO)

Note: Where “attributes”:[{“attribute_name”:” oof_returned_flavor_label_for_vgw_1 “,

Admin needs to ensure that this value is same as flavor parameter in HOT

{
    "hpa_constraint":{
        "type":"hpa",
        "demands":[
           "vG"
        ],
        "properties":{
           "evaluate":[
              {
                 "id": "vgw_0",
                 "type": "vnfc",
                 "directives": [
                    {
                     "type":"flavor_directives",
                     "attributes":[
                        {
                         "attribute_name":" oof_returned_flavor_label_for_vgw_0 ",
                         "attribute_value": "<Blank>"
                        }
                     ]
                    }
                 ],
                 "flavorProperties":[
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "True",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"numVirtualCpu",
                             "hpa-attribute-value":"32",
                             "operator":"="
                          }
                       ]
                    },
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "True",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"virtualMemSize",
                             "hpa-attribute-value":"64",
                             "operator":"=",
                             "unit":"GB"
                          }
                       ]
                    },
                    {
                       "hpa-feature":"ovsDpdk",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "False",
                       "score": "10",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"dataProcessingAccelerationLibrary",
                             "hpa-attribute-value":"v18.02",
                             "operator":"="
                          }
                       ]
                    },
                    {
                       "hpa-feature": "qosIntentCapabilities",
                       "mandatory": "True",
                       "architecture": "generic",
                       "hpa-version": "v1",
                       "directives": [],
                       "hpa-feature-attributes": [
                          {
                             "hpa-attribute-key":"Infrastructure Resource Isolation for VNF",
                             "hpa-attribute-value": "Burstable QoS",
                             "operator": "=",
                             "unit": ""
                          },
                          {  "hpa-attribute-key":"Burstable QoS Oversubscription Percentage",
                             "hpa-attribute-value": "25",
                             "operator": "=",
                             "unit": ""
                          }
                       ]
                    }
                 ]
              },
              {
                 "id": "vgw_1",
                 "type": "vnfc",
                 "directives": [
                    {
                     "type":"flavor_directives",
                     "attributes":[
                        {
                         "attribute_name":" oof_returned_flavor_label_for_vgw_1 ",
                         "attribute_value": "<Blank>"
                        }
                     ]
                    }
                 ],
                 "flavorProperties":[
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "False",
                       "score": "5",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"numVirtualCpu",
                             "hpa-attribute-value":"8",
                             "operator":">="
                          }
                       ]
                    },
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "False",
                       "score": "5",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"virtualMemSize",
                             "hpa-attribute-value":"16",
                             "operator":">=",
                             "unit":"GB"
                          }
                       ]
                    },
                    {
                       "hpa-feature":"sriovNICNetwork",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "True",
                       "directives": [
                          {
                            "type": "sriovNICNetwork_directives",
                            "attributes": [
                               { "attribute_name": "oof_returned_vnic_type_for_vgw_1",
                                 "attribute_value": "direct"
                               },
                               { "attribute_name": "oof_returned_provider_network_for_vgw_1",
                                 "attribute_value": "physnet2"
                               }
                            ]
                          }
                       ],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"pciVendorId",
                             "hpa-attribute-value":"8086",
                             "operator":"=",
                             "unit":""
                          },
                          {
                             "hpa-attribute-key":"pciDeviceId",
                             "hpa-attribute-value":"0443",
                             "operator":"=",
                             "unit":""
                          },
                          {
                             "hpa-attribute-key":"pciCount",
                             "hpa-attribute-value":"1",
                             "operator":"=",
                             "unit":""
                          },
                          {
                             "hpa-attribute-key":"physicalNetwork",
                             "hpa-attribute-value":"physnet2",
                             "operator":"=",
                             "unit":""
                          }
                       ]
                    }
                 ]
              }
           ]
        }
     }
  }

Example for Pure TOSCA request(VF-C)

{
    "hpa_constraint":{
        "type":"hpa",
        "demands":[
           "vG"
        ],
        "properties":{
           "evaluate":[
              {
                 "id": "vgw_0",
                 "type": "tocsa.nodes.nfv.Vdu.Compute",
                 "directives": [
                    {
                     "type":"flavor_directives",
                     "attributes":[
                        {
                         "attribute_name":" flavor_name ",
                         "attribute_value": "<Blank>"
                        }
                     ]
                    }
                 ],
                 "flavorProperties":[
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "True",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"numVirtualCpu",
                             "hpa-attribute-value":"32",
                             "operator":"="
                          }
                       ]
                    },
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "True",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"virtualMemSize",
                             "hpa-attribute-value":"64",
                             "operator":"=",
                             "unit":"GB"
                          }
                       ]
                    },
                    {
                       "hpa-feature":"ovsDpdk",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "False",
                       "score": "10",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"dataProcessingAccelerationLibrary",
                             "hpa-attribute-value":"v18.02",
                             "operator":"="
                          }
                       ]
                    },
                    {
                       "hpa-feature": "qosIntentCapabilities",
                       "mandatory": "True",
                       "architecture": "generic",
                       "hpa-version": "v1",
                       "directives": [],
                       "hpa-feature-attributes": [
                          {
                             "hpa-attribute-key":"Infrastructure Resource Isolation for VNF",
                             "hpa-attribute-value": "Burstable QoS",
                             "operator": "=",
                             "unit": ""
                          },
                          {  "hpa-attribute-key":"Burstable QoS Oversubscription Percentage",
                             "hpa-attribute-value": "25",
                             "operator": "=",
                             "unit": ""
                          }
                       ]
                    }
                 ]
              },
              {
                 "id": "vgw_1",
                 "type": "tosca.nodes.nfv.Vdu.Compute",
                 "directives": [
                    {
                     "type":"flavor_directives",
                     "attributes":[
                        {
                         "attribute_name":" flavor_name ",
                         "attribute_value": "<Blank>"
                        }
                     ]
                    }
                 ],
                 "flavorProperties":[
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "False",
                       "score": "5",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"numVirtualCpu",
                             "hpa-attribute-value":"8",
                             "operator":">="
                          }
                       ]
                    },
                    {
                       "hpa-feature":"basicCapabilities",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "False",
                       "score": "5",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"virtualMemSize",
                             "hpa-attribute-value":"16",
                             "operator":">=",
                             "unit":"GB"
                          }
                       ]
                    },
                    {
                       "hpa-feature":"sriovNICNetwork",
                       "hpa-version":"v1",
                       "architecture":"generic",
                       "mandatory": "True",
                       "directives": [],
                       "hpa-feature-attributes":[
                          {
                             "hpa-attribute-key":"pciVendorId",
                             "hpa-attribute-value":"8086",
                             "operator":"=",
                             "unit":""
                          },
                          {
                             "hpa-attribute-key":"pciDeviceId",
                             "hpa-attribute-value":"0443",
                             "operator":"=",
                             "unit":""
                          },
                          {
                             "hpa-attribute-key":"pciCount",
                             "hpa-attribute-value":"1",
                             "operator":"=",
                             "unit":""
                          },
                       ]
                    }
                 ]
              }
           ]
        }
     }
  }

VIM Fit

Constrain each demand’s inventory candidates based on capacity check for available capacity at the VIM instances.

Requirements are sent as an opaque request object understood by the VIM controllers or MultiCloud. Each controller is defined and implemented as a plugin in Conductor.

A vim controller plugin knows how to communicate with a particular endpoint (via HTTP/REST, DMaaP, etc.), obtain necessary information, and make a decision. The endpoint and credentials can be configured through plugin settings.

Schema

Property

Value

controller

Name of a vim controller. (e.g., multicloud)

request

Opaque dictionary of key/value pairs. Values must be strings or numbers. Encoded and sent to the vim controller via a plugin.

constraints:
  check_cloud_capacity:
    type: vim_fit
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      controller: multicloud
      request: REQUEST_DICT

Notes

  • For the current release the REQUEST_DICT is of the following format as defined by the policy for vim_fit. The REQUEST_DICT is an opaque request object defined through policy, so it is not restricted to this format. In the current release MultiCloud supports the check_vim_capacity using the following grammar.

    {
      "request":{
        "vCPU":10,
        "Memory":{
          "quantity":{
            "get_param":"REQUIRED_MEM"
          },
          "unit":"GB"
        },
        "Storage":{
          "quantity":{
            "get_param":"REQUIRED_DISK"
          },
          "unit":"GB"
        }
      }
    }
    

Inventory Group

Constrain demands such that inventory items are grouped across two demands.

This constraint has no properties.

constraints:
  my_group:
    type: inventory_group
    demands: [demand_1, demand_2]

Note: Only pair-wise groups are supported at this time. The list must have only two demands.

License

Constrain demands according to license availability.

Support for this constraint is deferred to a later release.

Schema

Property

Value

id

Unique license identifier

key

Opaque license key, particular to the license identifier

constraints:
  my_software:
    type: license
    demands: [demand_1, demand_2, ...]
    properties:
      id: SOFTWARE_ID
      key: LICENSE_KEY

Network Between Demands

Constrain each pairwise combination of two or more demands by network requirements.

Support for this constraint is deferred to a later release.

Schema

Property

Value

bandwidth (Optional)

Desired network bandwidth.

distance (Optional)

Desired distance between demands, measured by the network path.

latency (Optional)

Desired network latency.

Any combination of bandwidth, distance, or latency must be specified. If none of these properties are used, it is treated as a malformed request.

The constraint is applied between each pairwise combination of demands. For this reason, at least two demands must be specified, implicitly or explicitly.

constraints:
  network_requirements:
    type: network_between_demands
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      bandwidth: >= 1000 Mbps
      distance: < 250 km
      latency: < 50 ms

Network To Location

Constrain one or more demands by network requirements relative to a specific location.

Support for this constraint is deferred to a later release.

Schema

Property

Value

bandwidth

Desired network bandwidth.

distance

Desired distance between demands, measured by the network path.

latency

Desired network latency.

location

A previously declared location.

Any combination of bandwidth, distance, or latency must be specified. If none of these properties are used, it is treated as a malformed request.

The constraint is applied between each demand and the referenced location, not across all pairwise combinations of Demands.

constraints:
  my_access_network_constraint:
    type: network_to_location
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      bandwidth: >= 1000 Mbps
      distance: < 250 km
      latency: < 50 ms
      location: LOCATION_ID

Capabilities

Constrain each demand by its cluster capability requirements. For example, as described by an OpenStack Heat template and operational environment.

Support for this constraint is deferred to a later release.

Schema

Property

Value

specification

Indicates the kind of specification being provided in the properties. Must be heat. Future values may include tosca, Homing, etc.

template

For specifications of type heat, a single stack in OpenStack Heat Orchestration Template (HOT) format. Stacks may be expressed as a URI reference or a string of well-formed YAML/JSON. Templates are validated by the Heat service configured for use by HAS. Nested stack references are unsupported.

environment

(Optional)

For specifications of type heat, an optional Heat environment. Environments may be expressed as a URI reference or a string of well-formed YAML/JSON. Environments are validated by the Heat service configured for use by Homing.

constraints:
  check_for_fit:
    type: capability
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      specification: heat
      template: http://repository/my/stack_template
      environment: http://repository/my/stack_environment

Threshold

Constrain each demand by an attribute which is within a certain threshold.

Schema

Property

Value

evaluate

List of attributes and its threshold

Property for evaluation

Value

attribute

Attribute of a candidate

threshold

Threshold Value

operator

Condition to check. Supported Values are gte, lte, lt, gt, eq

unit (optional)

Attribute’s unit of measurement

urllc_threshold:
  type: threshold
  demands: ['URLLC']
  properties:
    evaluate:
    - attribute: latency
      operator: lte
      threshold: 50
      unit: ms
    - attribute: reliability
      operator: gte
      threshold: 99.99

Note:

  • The status of the constraint support is of Frankfurt release.

Reservations

A Reservation allows reservation of resources associated with candidate that satisfies one or more demands.

Similar to the instance_fit constraint, requirements are sent as a request to a service controller that handles the reservation. Service controllers are defined by plugins in Homing (e.g., sdn-c).

The service controller plugin knows how to make a reservation (and initiate rollback on a failure) with a particular endpoint (via HTTP/REST, DMaaP, etc.) of the service controller. The endpoint and credentials can be configured through plugin settings.

Schema

Property

Description

controller

Name of a service controller.

request

Opaque dictionary of key/value pairs. Values must be strings or numbers. Encoded and sent to the service provider via a plugin.

resource_reservation:
  type: instance_reservation
  demands: [my_vnf_demand, my_other_vnf_demand]
  properties:
    controller: sdn-c
    request: REQUEST_DICT

Optimizations

An Optimization allows specification of a objective function, which aims to maximize or minimize a certain value that varies based on the choice of candidates for one or more demands that are a part of the objective function. For example, an objective function may be to find the closest cloud-region to a customer to home a demand.

Optimization Components

Optimization definitions can be broken down into three components:

Compo nent

Key

Value

Goal

minimize

A single Operand (usually sum) or Function

Opera tor

sum, product

Two or more Operands (Numbers, Operators, Functions)

Funct ion

distance_bet ween

A two-element list consisting of a location and demand.

Example

Given a customer location cl, two demands vG1 and vG2, and weights w1 and w2, the optimization criteria can be expressed as:

minimize(weight1 * distance_between(cl, vG1) + weight2 * distance_between(cl, vG2))

This can be read as: “Minimize the sum of weighted distances from cl to vG1 and from cl to vG2.”

Such optimizations may be expressed in a template as follows:

parameters:
  w1: 10
  w2: 20

optimization:
  minimize:
    sum:
    - product:
      - {get_param: w1}
      - {distance_between: [cl, vG1]}
    - product:
      - {get_param: w2}
      - {distance_between: [cl, vG2]}

Or without the weights as:

optimization:
  minimize:
    sum:
    - {distance_between: [cl, vG1]}
    - {distance_between: [cl, vG2]}

Template Restriction

While the template format supports any number of arrangements of numbers, operators, and functions, HAS’s solver presently expects a very specific arrangement.

  • Optimizations must conform to a single goal of minimize followed by a sum operator.

  • The sum can consist of two distance_between function calls, or two product operators.

  • If a product operator is present, it must contain at least a distance_between function call, plus one optional number to be used for weighting.

  • Numbers may be referenced via get_param.

  • The objective function has to be written in the sum-of-product format. In the future, HAS can convert product-of-sum into sum-of-product automatically.

The first two examples in this section illustrate both of these use cases.

Inline Operations

If desired, operations can be rewritten inline. For example, the two product operations from the previous example can also be expressed as:

parameters:
  w1: 10
  w2: 20

optimization:
  minimize:
    sum:
    - {product: [{get_param: w1}, {distance_between: [cl, vG1]}]}
    - {product: [{get_param: w2}, {distance_between: [cl, vG2]}]}

In turn, even the sum operation can be rewritten inline, however there is a point of diminishing returns in terms of readability!

Notes

  • We do not support more than one dimension in the optimization (e.g., Minimize distance and cost). For supporting multiple dimensions we would need a function the normalize the unit across dimensions.

Intrinsic Functions

Homing provides a set of intrinsic functions that can be used inside templates to perform specific tasks. The following section describes the role and syntax of the intrinsic functions.

Functions are written as a dictionary with one key/value pair. The key is the function name. The value is a list of arguments. If only one argument is provided, a string may be used instead.

a_property: {FUNCTION_NAME: [ARGUMENT_LIST]}

a_property: {FUNCTION_NAME: ARGUMENT_STRING}

Note: These functions can only be used within “properties” sections.

get_file

The get_file function inserts the content of a file into the template. It is generally used as a file inclusion mechanism for files containing templates from other services (e.g., Heat).

The syntax of the get_file function is:

{get_file: <content key>}

The content key is used to look up the files dictionary that is provided in the REST API call. The Homing client command (Homing) is get_file aware and populates the files dictionary with the actual content of fetched paths and URLs. The Homing client command supports relative paths and transforms these to the absolute URLs required by the Homing API.

Note: The get_file argument must be a static path or URL and not rely on intrinsic functions like get_param. The Homing client does not process intrinsic functions. They are only processed by the Homing engine.

The example below demonstrates the get_file function usage with both relative and absolute URLs:

constraints:
  check_for_fit:
    type: capacity
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      template: {get_file: stack_template.yaml}
      environment: {get_file: http://hostname/environment.yaml}

The files dictionary generated by the Homing client during instantiation of the plan would contain the following keys. Each value would be of that file’s contents.

  • file:///path/to/stack_template.yaml

  • http://hostname/environment.yaml

Note

  • If Homing will only be accessed over DMaaP, files will need to be embedded using the Homing API request format. This will be a consideration when DMaaP integration happens.

get_param

The get_param function references an input parameter of a template. It resolves to the value provided for this input parameter at runtime.

The syntax of the get_param function is:

{get_param: <parameter name>}

{get_param: [<parameter name>, <key/index1> (optional), <key/index2> (optional), ...]}

parameter name is the parameter name to be resolved. If the parameters returns a complex data structure such as a list or a dict, then subsequent keys or indices can be specified. These additional parameters are used to navigate the data structure to return the desired value. Indices are zero-based.

The following example demonstrates how the get_param function is used:

parameters:
  software_id: SOFTWARE_ID
  license_key: LICENSE_KEY
  service_info:
    provider: dmaap:///full.topic.name
    costs: [10, 20, 30, 40, 50, 60, 70, 80, 90, 100]

constraints:
  my_software:
    type: license
    demands: [demand_1, demand_2, ...]
    properties:
      id: {get_param: software_id}
      key: {get_param: license_key}

  check_for_availability:
    type: service
    demands: [my_vnf_demand, my_other_vnf_demand]
    properties:
      provider_url: {get_param: [service_info, provider]}
      request: REQUEST_DICT
      cost: {get_param: [service_info, costs, 4]}

In this example, properties would be set as follows:

Key

Value

id

SOFTWARE_ID

key

LICENSE_KEY

provider_url

dmaap:///full.topic.name

cost

50

Contact

Shankar Narayanan shankarpnsn@gmail.com