Merge "blueprint for bgpaas-peer-selection"

5.1/bgpaas-peer-selection.md

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+# 1. Introduction
+The BGPaaS has to support control-node-zone selection.
+Configuration option would be given in BGPaaS to choose control-node-zones
+to which it has to be peered.
+
+# 2. Problem statement
+Service Providers are relying on BGPaaS for routing from/to VNF.
+VNFs are made up of several nodes spread on different computes.
+VNFs will usually rely on two bgp peers for High Availablity.
+All BGP peers from a VNF can be terminated onto the same control node.
+If the control node fails, both primary and secondary peer get lost at
+the same time. It will break the High Availablity.
+
+# 3. Proposed solution
+In the BGPaaS configuration, option would be given to choose primary and
+secondary control-node-zones. Control-node-zones can have one or more
+control-nodes. If control-node-zone has more than one control-nodes, one will
+be choosen randomly as peer. Existing model would be followed if
+control-node-zone is not configured(i.e if either primary/secondary or both
+control-node-zone(s) are configured, existing model would not be followed)
+
+## 3.1 Alternatives considered None.
+
+## 3.2 API schema changes
+New Ifmap identifier control-node-zone will be added as a child to
+global-system-config.
+    <xsd:element name="control-node-zone" type="ifmap:IdentityType"/>
+    <xsd:element name="global-system-config-bgp-router"/>
+    <!--#IFMAP-SEMANTICS-IDL
+        Link('global-system-config-bgp-router',
+                'global-system-config', 'bgp-router', ['ref'], 'required', 'R',
+                'List of references to all bgp routers in systems.') -->
+
+Link will be added between bgp-router and control-node-zone.
+    <xsd:element name="bgp-router-control-node-zone"/>
+    <!--#IFMAP-SEMANTICS-IDL
+        Link('bgp-router-control-node-zone',
+            'bgp-router', 'control-node-zone', ['ref'], 'optional', 'CRUD',
+            'This bgp-router belongs to the referenced control-node-zone.') -->
+
+Attribute type of BgpaasBgpRouterType will be added in bgpaas-bgp-router to
+select primary and secondary control-node-zones.
+    <xsd:complexType name="BgpaasBgpRouterType">
+        <xsd:all>
+            <xsd:element name="primary-zone" type="xsd:string" required='optional'
+             description='control-node-zone for bgp-peering for x.x.x.1 gateway'/>
+            <xsd:element name="secondary-zone" type="xsd:string" required='optional'
+             description='control-node-zone for bgp-peering for x.x.x.2 gateway'/>
+        </xsd:all>
+    </xsd:complexType>
+    <xsd:element name="bgpaas-bgp-router" type="BgpaasBgpRouterType"/>
+    <!--#IFMAP-SEMANTICS-IDL
+        Link('bgpaas-bgp-router', 'bgp-as-a-service', 'bgp-router', ['ref'], 'system-only', 'CRUD',
+            'Reference to internal BGP peer object automatically generated by the system.') -->
+
+## 3.3 User workflow impact
+User is expected to configure control-node-zones and select primary and
+secondary zone in BGPaaS
+Any configuration change would be applied to new BGPaaS sessions. Existing
+flows wont be affected.
+If Existing flows are affected for any reasons, new flows would be set with
+current BGPaaS configuration.
+
+## 3.4 UI changes
+Global-System-Config will have an option to add/modify/delete control-node-zones
+Control-Node-Zone will have an option to add/modify/delete control-nodes
+Bgp-Router will have an option to add/modify/delete control-node-zone.
+BGPaaS will have an option to add/modify/delete primary and secondary
+control-node-zone.
+
+## 3.5 Notification impact
+
+# 4. Implementation
+
+## 4.1 Work items
+
+### 4.1.1 Vrouter Agent changes
+Contrail-vrouter-agent will get control-node-zone and bgp-router
+configuration from respective ifmap nodes. It will also get primary
+and secondary control-node-zone names from bgpaas-bgp-router attribute.
+BGPaaS in the contrail-vrouter-agent will construct primary and secondary
+bgp-peers(control-nodes) from control-node-zones. If VNF uses x.x.x.1,
+bgp-peer will be selected from primary. If it uses x.x.x.2, bgp-peer
+will be selected from secondary. [Selecting bgp-peer in primary/
+secondary is random.]. If control-node-zone is not configured in BGPaas,
+it will follow the existing model(choose first xmpp server for x.x.x.1
+and second xmpp server for x.x.x.2)
+
+### 4.1.2 Vrouter changes
+There are no vrouter changes.
+
+## 4.2 Limitations
+
+# 5. Performance and scaling impact
+## 5.1 API and control plane
+#### Scaling and performance for API and control plane
+
+## 5.2 Forwarding performance
+#### Scaling and performance for API and forwarding
+
+# 6. Upgrade
+None
+
+# 7. Deprecations
+None
+
+# 8. Dependencies
+None.
+
+# 9. Testing
+## 9.1 Unit tests
+a) Configure BGPaaS with primary/secondary control-node-zone and check the
+bgp-peer
+b) Configure BGPaaS without control-node-zone and check it follows the existing
+model.
+c) Stop all control-nodes in primary control-node-zone and see if bgpaas peer
+does not re-establish
+d) Stop all control-nodes in secondary control-node-zone and see if bgpaas peer
+does not re-establish
+
+## 9.2 System tests
+
+# 10. Documentation Impact
+
+# 11. References