1 .. This work is licensed under a Creative Commons Attribution 4.0 International License.
2 .. http://creativecommons.org/licenses/by/4.0
8 Domino provides a distribution service for Network Service Descriptors (NSDs) and
9 Virtual Network Function Descriptors (VNFDs) that are composed using Tosca Simple
10 Profile for Network Functions Virtualization
11 (http://docs.oasis-open.org/tosca/tosca-nfv/v1.0/tosca-nfv-v1.0.html).
12 Domino service is targeted towards supporting many Software Defined Network (SDN) controllers,
13 Service Orchestrators (SOs), VNF Managers (VNFMs), Virtual Infastructure Managers (VIMs),
14 Operation and Business Support Systems that produce and/or consume NSDs and VNFDs.
16 Producers of NSDs and VNFDs use Domino Service through Service Access Points (SAPs) or End Points (EPs)
17 to publish these descriptors. Consumers of NSDs and VNFDs subscribe with the Domino Service through
18 the same SAPs/EPs and declare their resource capabilities to onboard and perform Life Cycle Management
19 (LCM) for Network Services (NSs) and Virtual Network Functions (VNFs). Thus, Domino acts as a service
20 broker for NSs and VNFs modeled in a Tosca template.
22 =============================
23 Domino Capabilities and Usage
24 =============================
29 Domino's pub/sub architecture is based on labels (see Fig. 1 below).
30 Each Template Producer and Template Consumer is expected to run a local Domino Client
31 to publish templates and subscribe for labels.
35 .. figure:: ../../etc/domino_pubsub_system.jpeg
40 :figclass: align-center
42 Domino provides a pub/sub server for NSDs and VNFDs
44 Domino Service does not interpret what the labels mean. Domino derives labels directly from
45 the normative definitions in TOSCA Simple YAML Profile for NFV. Domino parses the policy
46 rules included in the NSD/VNFD, form "policy" labels, and determine which resources are
47 associated with which set of labels. Domino identifies which Domino Clients can host
48 which resource based on the label subscriptions by these clients. Once mapping of resources
49 to the clients are done, new NSDs/VNFDs are created based on the mapping. These new
50 NSDs/VNFDs are translated and delivered to the clients.
52 Label Format and Examples
53 =========================
55 Domino supports policy labels in the following form:
59 <policytype>:properties:<key:value>
61 Orchestrators, controllers, and managers use Domino service to announce their
62 capabilities by defining labels in this form and subscribing for these labels with
65 For instance a particular VIM that is capable of performing an
66 affinity based VNF or VDU placement at host machine granularity can specify a label
71 tosca.policies.Placement.affinity:properties:granularity:hostlevel
73 When the VIM registers with the Domino Service and subscribed for that label, Domino views
74 this VIM as a candidate location that can host a VNF or VDU requesting affinity based
75 placement policy at host machine granularity.
77 Another use case is the announcement of lifecycle management capabilities for VNFs and
78 VNF Forwarding Graphs (VNFFG) by different SDN Controllers (SDN-Cs), VNFMs, or VIMs.
83 tosca.policies.Scaling.VNFFG:properties:session_continuity:true
85 can be used as a label to indicate that when a scaling operation on a VNFFG (e.g., add
86 more VNFs into the graph) is requested, existing session can still be enforced to go
87 through the same chain of VNF instances.
89 To utilize Domino's domain mapping services for virtual network resources (e.g., VNF, VDU,
90 VNFFG, CP, VL, etc.), a network service or network function request must include
91 policy rules that are composed of policy types and property values that match to the
92 label announcements made by these domains. For instance, when a TOSCA template includes a
93 policy rule with type "tosca.policies.Scaling.VNFFG" and property field
94 "session_continuity" set as "true" targeting one or more VNFFGs, this serves as the hint
95 for the Domino Server to identify all the Domain Clients that subscribed the label
96 "tosca.policies.Scaling.VNFFG:properties:session_continuity:true".
98 Template Example for Label Extraction
99 =====================================
101 Consider the following NSD TOSCA template:
105 tosca_definitions_version: tosca_simple_profile_for_nfv_1_0_0
106 description: Template for deploying a single server with predefined properties.
108 template_name: TOSCA NFV Sample Template
110 tosca.policies.Placement.Geolocation:
111 description: Geolocation policy
112 derived_from: tosca.policies.Placement
116 type: tosca.nodes.nfv.VNF
122 type: tosca.nodes.nfv.VNF
128 type: tosca.nodes.nfv.VNF
135 type: tosca.policies.Placement.Geolocation
138 region: [ us-west-1 ]
140 type: tosca.policies.Placement.Geolocation
141 targets: [ VNF2, VNF3 ]
143 region: [ us-west-1 , us-west-2 ]
145 Domino Server extracts all possible policy labels by exhaustively concatenating key-value
146 pairs under the properties section of the policy rules to the policy type of these rules:
150 tosca.policies.Placement.Geolocation:properties:region:us-west-1
151 tosca.policies.Placement.Geolocation:properties:region:us-west-2
153 Furthermore, Domino Server iterates over the targets specified under policy rules to generate a set of labels for each target node:
157 required_labels['VNF1'] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 }
158 required_labels['VNF2'] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 , tosca.policies.Placement.Geolocation:properties:region:us-west-2}
159 required_labels['VNF3'] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 , tosca.policies.Placement.Geolocation:properties:region:us-west-2}
161 When a Template Consuming site (e.g., VNFM or VIM) registers with the Domino Server using
162 Domino Client, it becomes an eligible candidate for template distribution with an initially
163 empty set of label subscriptions. Suppose three different Domino Clients register with the
164 Domino Server and subscribe for some or none of the policy labels such that the Domino Server
165 has the current subscription state as follows:
169 subscribed_labels[site-1] = { } #this is empty set
170 subscribed_labels[site-2] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 }
171 subscribed_labels[site-3] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 , tosca.policies.Placement.Geolocation:properties:region:us-west-2}
174 Based on the TOSCA example and hypothetical label subscriptions above, Domino Server identifies
175 all the VNFs can be hosted by Site-3, while VNF1 can be hosted by both Site-2 and Site-3.
176 Note that Site-1 cannot host any of the VNFs listed in the TOSCA file. When a VNF can be hosted
177 by multiple sites, Domino Server picks the site that can host the most number of VNFs. When not
178 all VNFs can be hosted on the same site, the TOSCA file is partitioned into multiple files, one
179 for each site. These files share a common part (e.g, meta-data, policy-types, version,
180 description, virtual resources that are not targeted by any policy rule, etc.). Each site
181 specific file has also a non-common part that only appears in that file (i.e., virtual
182 resources explicitly assigned to that site and the policy rules that accompany those virtual
185 In the current Domino convention, if a VNF (or any virtual resource) does not have a policy
186 rule (i.e., it is not specified as a target in any of the policy rules) and it also is not
187 dependent on any VNF (or any virtual resource) that is assigned to another site, that resource
188 is wild carded by default and treated as part of the "common part". Also note that currently
189 Domino does not support all or nothing semantics: if some of the virtual resources are not
190 mappable to any domain because they are targets of policy rules that are not supported by any
191 site, these portions will be excluded while the remaining virtual resources will be still be
192 part of one or more template files to be distributed to hosting sites. When NSDs and VNFDs are
193 prepared, these conventions must be kept in mind. In the future releases, these conventions can
194 change based on the new use cases.
196 For the example above, no partitioning would occur as all VNFs are mapped onto site-3;
197 Domino Server simply delivers the Tosca file to Domino Client hosted on site-3. When TOSCA
198 cannot be consumed by a particular site directly, Domino Server can utilize
199 existing translators (e.g., heat-translator) to first translate the template before delivery.
201 Internal Processing Pipeline at Domino Server
202 =============================================
204 Fig. 2 shows the block diagram for the processing stages of a published TOSCA template.
205 Domino Client issues an RPC call publish(tosca file). Domino Server passes the received tosca
206 file to Label Extractor that outputs resource labels. Domain Mapper uses the extracted labels
207 and tosca file to find mappings from resources to domains as well as the resource dependencies.
208 Resource to domain mappings and resource dependencies are utilized to partition the
209 orchestration template into individual resource orchestration templates (one for each domain).
210 If a translation is required (e.g., TOSCA to HOT), individual resource orchestration templates
211 are first translated and then placed on a template distribution workflow based on resource
212 dependencies. Message Sender block in the server takes one distribution task at a time from the
213 workflow generator and pushes the orchestration template to the corresponding Domino Client.
217 .. figure:: ../../etc/domino_server_processing.png
222 :figclass: align-center
224 Domino Service Processing Pipeline
229 Domino Service currently supports maximum packing strategy when a virtual resource type can
230 be hosted on multiple candidate sites. Initially, Domino Scheduler identifies virtual resources
231 that has only one feasible site for hosting. Each such virtual resource is trivially assigned
232 to its only feasible site. The remaining virtual resources with multiple candidate locations
233 are sequentially allocated to one of their candidate locations that has the most virtual
234 resource assignments so far. Note that wildcarded resources are assigned to all sites. To
235 prevent wildcarding within the current release, (i) all sites must subscribed to a base policy
236 with a dummy key-value pair defined under the properties tab and (ii) all the independent
237 resources must be specified as target of that policy in NSD or VNFD file.