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diff --git a/docs/development/overview/feature.overview.rst b/docs/development/overview/feature.overview.rst new file mode 100644 index 0000000..4ef8d16 --- /dev/null +++ b/docs/development/overview/feature.overview.rst @@ -0,0 +1,237 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +================== +Domino Description +================== + +Domino provides a distribution service for Network Service Descriptors (NSDs) and +Virtual Network Function Descriptors (VNFDs) that are composed using Tosca Simple +Profile for Network Functions Virtualization +(http://docs.oasis-open.org/tosca/tosca-nfv/v1.0/tosca-nfv-v1.0.html). +Domino service is targeted towards supporting many Software Defined Network (SDN) controllers, +Service Orchestrators (SOs), VNF Managers (VNFMs), Virtual Infastructure Managers (VIMs), +Operation and Business Support Systems that produce and/or consume NSDs and VNFDs. + +Producers of NSDs and VNFDs use Domino Service through Service Access Points (SAPs) or End Points (EPs) +to publish these descriptors. Consumers of NSDs and VNFDs subscribe with the Domino Service through +the same SAPs/EPs and declare their resource capabilities to onboard and perform Life Cycle Management +(LCM) for Network Services (NSs) and Virtual Network Functions (VNFs). Thus, Domino acts as a service +broker for NSs and VNFs modeled in a Tosca template. + +============================= +Domino Capabilities and Usage +============================= + +Labels in Domino +================ + +Domino's pub/sub architecture is based on labels (see Fig. 1 below). +Each Template Producer and Template Consumer is expected to run a local Domino Client +to publish templates and subscribe for labels. + +.. _fig-label: + +.. figure:: ../../etc/domino_pubsub_system.jpeg + :width: 350px + :align: center + :height: 300px + :alt: alternate text + :figclass: align-center + + Domino provides a pub/sub server for NSDs and VNFDs + +Domino Service does not interpret what the labels mean. Domino derives labels directly from +the normative definitions in TOSCA Simple YAML Profile for NFV. Domino parses the policy +rules included in the NSD/VNFD, form "policy" labels, and determine which resources are +associated with which set of labels. Domino identifies which Domino Clients can host +which resource based on the label subscriptions by these clients. Once mapping of resources +to the clients are done, new NSDs/VNFDs are created based on the mapping. These new +NSDs/VNFDs are translated and delivered to the clients. + +Label Format and Examples +========================= + +Domino supports policy labels in the following form: + +.. code-block:: bash + + <policytype>:properties:<key:value> + +Orchestrators, controllers, and managers use Domino service to announce their +capabilities by defining labels in this form and subscribing for these labels with +the Domino Server. + +For instance a particular VIM that is capable of performing an +affinity based VNF or VDU placement at host machine granularity can specify a label +in the form: + +.. code-block:: bash + + tosca.policies.Placement.affinity:properties:granularity:hostlevel + +When the VIM registers with the Domino Service and subscribed for that label, Domino views +this VIM as a candidate location that can host a VNF or VDU requesting affinity based +placement policy at host machine granularity. + +Another use case is the announcement of lifecycle management capabilities for VNFs and +VNF Forwarding Graphs (VNFFG) by different SDN Controllers (SDN-Cs), VNFMs, or VIMs. +For instance + +.. code-block:: bash + + tosca.policies.Scaling.VNFFG:properties:session_continuity:true + +can be used as a label to indicate that when a scaling operation on a VNFFG (e.g., add +more VNFs into the graph) is requested, existing session can still be enforced to go +through the same chain of VNF instances. + +To utilize Domino's domain mapping services for virtual network resources (e.g., VNF, VDU, +VNFFG, CP, VL, etc.), a network service or network function request must include +policy rules that are composed of policy types and property values that match to the +label announcements made by these domains. For instance, when a TOSCA template includes a +policy rule with type "tosca.policies.Scaling.VNFFG" and property field +"session_continuity" set as "true" targeting one or more VNFFGs, this serves as the hint +for the Domino Server to identify all the Domain Clients that subscribed the label +"tosca.policies.Scaling.VNFFG:properties:session_continuity:true". + +Template Example for Label Extraction +===================================== + +Consider the following NSD TOSCA template: + +.. code-block:: bash + + tosca_definitions_version: tosca_simple_profile_for_nfv_1_0_0 + description: Template for deploying a single server with predefined properties. + metadata: + template_name: TOSCA NFV Sample Template + policy_types: + tosca.policies.Placement.Geolocation: + description: Geolocation policy + derived_from: tosca.policies.Placement + topology_template: + node_templates: + VNF1: + type: tosca.nodes.nfv.VNF + properties: + id: vnf1 + vendor: acmetelco + version: 1.0 + VNF2: + type: tosca.nodes.nfv.VNF + properties: + id: vnf2 + vendor: ericsson + version: 1.0 + VNF3: + type: tosca.nodes.nfv.VNF + properties: + id: vnf3 + vendor: huawei + version: 1.0 + policies: + - rule1: + type: tosca.policies.Placement.Geolocation + targets: [ VNF1 ] + properties: + region: [ us-west-1 ] + - rule2: + type: tosca.policies.Placement.Geolocation + targets: [ VNF2, VNF3 ] + properties: + region: [ us-west-1 , us-west-2 ] + +Domino Server extracts all possible policy labels by exhaustively concatenating key-value +pairs under the properties section of the policy rules to the policy type of these rules: + +.. code-block:: bash + + tosca.policies.Placement.Geolocation:properties:region:us-west-1 + tosca.policies.Placement.Geolocation:properties:region:us-west-2 + +Furthermore, Domino Server iterates over the targets specified under policy rules to generate a set of labels for each target node: + +.. code-block:: bash + + required_labels['VNF1'] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 } + required_labels['VNF2'] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 , tosca.policies.Placement.Geolocation:properties:region:us-west-2} + required_labels['VNF3'] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 , tosca.policies.Placement.Geolocation:properties:region:us-west-2} + +When a Template Consuming site (e.g., VNFM or VIM) registers with the Domino Server using +Domino Client, it becomes an eligible candidate for template distribution with an initially +empty set of label subscriptions. Suppose three different Domino Clients register with the +Domino Server and subscribe for some or none of the policy labels such that the Domino Server +has the current subscription state as follows: + +.. code-block:: bash + + subscribed_labels[site-1] = { } #this is empty set + subscribed_labels[site-2] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 } + subscribed_labels[site-3] = { tosca.policies.Placement.Geolocation:properties:region:us-west-1 , tosca.policies.Placement.Geolocation:properties:region:us-west-2} + + +Based on the TOSCA example and hypothetical label subscriptions above, Domino Server identifies +all the VNFs can be hosted by Site-3, while VNF1 can be hosted by both Site-2 and Site-3. +Note that Site-1 cannot host any of the VNFs listed in the TOSCA file. When a VNF can be hosted +by multiple sites, Domino Server picks the site that can host the most number of VNFs. When not +all VNFs can be hosted on the same site, the TOSCA file is partitioned into multiple files, one +for each site. These files share a common part (e.g, meta-data, policy-types, version, +description, virtual resources that are not targeted by any policy rule, etc.). Each site +specific file has also a non-common part that only appears in that file (i.e., virtual +resources explicitly assigned to that site and the policy rules that accompany those virtual +resources. + +In the current Domino convention, if a VNF (or any virtual resource) does not have a policy +rule (i.e., it is not specified as a target in any of the policy rules) and it also is not +dependent on any VNF (or any virtual resource) that is assigned to another site, that resource +is wild carded by default and treated as part of the "common part". Also note that currently +Domino does not support all or nothing semantics: if some of the virtual resources are not +mappable to any domain because they are targets of policy rules that are not supported by any +site, these portions will be excluded while the remaining virtual resources will be still be +part of one or more template files to be distributed to hosting sites. When NSDs and VNFDs are +prepared, these conventions must be kept in mind. In the future releases, these conventions can +change based on the new use cases. + +For the example above, no partitioning would occur as all VNFs are mapped onto site-3; +Domino Server simply delivers the Tosca file to Domino Client hosted on site-3. When TOSCA +cannot be consumed by a particular site directly, Domino Server can utilize +existing translators (e.g., heat-translator) to first translate the template before delivery. + +Internal Processing Pipeline at Domino Server +============================================= + +Fig. 2 shows the block diagram for the processing stages of a published TOSCA template. +Domino Client issues an RPC call publish(tosca file). Domino Server passes the received tosca +file to Label Extractor that outputs resource labels. Domain Mapper uses the extracted labels +and tosca file to find mappings from resources to domains as well as the resource dependencies. +Resource to domain mappings and resource dependencies are utilized to partition the +orchestration template into individual resource orchestration templates (one for each domain). +If a translation is required (e.g., TOSCA to HOT), individual resource orchestration templates +are first translated and then placed on a template distribution workflow based on resource +dependencies. Message Sender block in the server takes one distribution task at a time from the +workflow generator and pushes the orchestration template to the corresponding Domino Client. + +.. _fig-pipe: + +.. figure:: ../../etc/domino_server_processing.png + :width: 400px + :align: center + :height: 350px + :alt: alternate text + :figclass: align-center + + Domino Service Processing Pipeline + +Resource Scheduling +=================== + +Domino Service currently supports maximum packing strategy when a virtual resource type can +be hosted on multiple candidate sites. Initially, Domino Scheduler identifies virtual resources +that has only one feasible site for hosting. Each such virtual resource is trivially assigned +to its only feasible site. The remaining virtual resources with multiple candidate locations +are sequentially allocated to one of their candidate locations that has the most virtual +resource assignments so far. Note that wildcarded resources are assigned to all sites. To +prevent wildcarding within the current release, (i) all sites must subscribed to a base policy +with a dummy key-value pair defined under the properties tab and (ii) all the independent +resources must be specified as target of that policy in NSD or VNFD file. |