--- /dev/null
+
+.. contents:: Table of Contents
+ :depth: 3
+
+=====================
+OVSDB Reconciliation
+=====================
+
+https://git.opendaylight.org/gerrit/#/q/topic:ovsdb-reconciliation
+
+Add support for reconciliation in ovsdb for tunnel interfaces and bridges.
+
+
+Problem description
+===================
+
+We don't want anybody to tinker with switch configuration for entities
+owned by the controller, switch configuration should be identical
+to what is there in the controller config.
+
+Use Cases
+---------
+The following usecases are supported
+
+* Use case 1: Reconciliation after controller reboot
+* Use case 2: Reconciliation after switch re-connection
+* Use case 3: Reconciliation after controller upgrade
+* Use case 4: Reconciliation after switch connects back to
+ different controller in a cluster of controllers
+* Use case 5: Reconciliation should happen in both controller
+ initiated and switch initiated connections
+
+
+Proposed change
+===============
+
+Controller should do reconciliation only on entities owned by the controller.
+For this we need to identify entities created by controller. Currently we use
+the key-value pair "opendaylight-iid:"operational datastore node Id" to stamp
+the entities created by the controller, but for a future proof solution this
+feature will add another key-value pair "created_by:odl" to stamp the entities
+created by the controller. This key-value pair will go in the external_ids
+column of ovsdb tables in switch.
+
+This feature will support only create and delete reconciliation, create
+reconciliation is already implemented, see references 3 & 4. Update reconciliation
+is not supported in this feature. Bridge and tunnel interface delete reconciliations
+are handled in this feature. This feature should handle both switch initiated and
+controller initiated connections.
+
+In order to handle reconciliation in a generic way, we will follow below steps
+
+#. Switch connects
+#. Check whether upgrade is going on
+#. if upgrade flag is not set, reconcile and publish the switch
+#. if flag is set, publish switch and reconcile when upgrade flag is down
+
+In current implementation both reconciliation and publishing to Oper DS are
+two parallel tasks. Reconciliation will be done in datastore transact commands
+where we compare, switch configuration got from OVSDB monitor callback and what
+is there in config datastore.
+
+The Scope of the reconciliation will be kept only to br-int bridge. Support for
+delete reconciliation for Qos Service is not in this scope of this spec.
+
+**Handling various scenarios**
+
+* Non upgrade scenario(upgrade flag is down)
+ - New switch connects: There is no configuration in the controller and switch,
+ first reconciliation kicks in, nothing to reconcile, then publishes switch
+ to oper DS.
+
+ - Existing switch flaps: There is same configuration in both controller and switch,
+ reconciliation code retains the same in switch, then switch gets published to OperDS
+ Switch connect is not the trigger for every config reconciliation. Currently
+ Bridge configuration reconciliation is getting triggered upon gaining eos ownership and
+ TerminationPoint reconciliation is getting triggered after the bridge appears
+ in oper datastore.
+
+ - Existing switch flaps with some change in configuration: Here create reconciliation
+ should push the new configuration to switch, and delete reconciliation should delete
+ the old ones, and push the switch to Oper DS.
+
+* Auto-Tunnel scenario (non upgrade, upgrade flag is down)
+ - New switch connects: same as above
+
+ - Existing switch flaps: same as above
+
+ - Existing switch flaps with change in tep/tz configuration: delete reconciliation should
+ delete the old tunnels and publish to Oper DS, now auto-tunnel module should take care
+ of creating new teps.
+
+* Upgrade scenario (replay based upgrade, upgrade flag will be set for sometime)
+ - New switch connects: if upgrade flag is set don't reconcile, publish the switch to Oper
+ DS, when upgrade flag is down, reconcile
+
+ - existing switch connects back: same as above
+
+ - existing switch connects back(auto-tunnel): when switch connects back, check upgrade flag.
+ If flag is set, dont reconcile, publish switch to Oper DS. When upgrade flag becomes down,
+ reconcile.
+
+In certain scenarios there will be traffic hit, like when we do reconciliation while system is
+updrading
+
+#. If Itm auto-tunnel module didn't get a chance to run before upgrade flag goes down, and if ovsdb
+ plugin runs first, then it will delete all the teps first, which will result in a traffic hit.
+#. If switch connects after the upgrade flag is down, then reconciliation will delete all the teps,
+ this also will result in a traffic hit
+
+
+Pipeline changes
+----------------
+None. This is OVSDB plugin
+
+Yang changes
+------------
+None.
+
+Configuration impact
+---------------------
+None
+
+Clustering considerations
+-------------------------
+Reconciliation should work in a clustered environment.
+
+Other Infra considerations
+--------------------------
+None
+
+Security considerations
+-----------------------
+None
+
+Scale and Performance Impact
+----------------------------
+None
+
+Targeted Release
+-----------------
+Neon
+
+Alternatives
+------------
+N.A.
+
+Usage
+=====
+
+Features to Install
+-------------------
+This feature doesn't add any new karaf feature.
+Installing OVSDB, genius or netvirt will install this feature.
+
+REST API
+--------
+No new REST APIs are added.
+
+CLI
+---
+None
+
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+ Nobin Mathew
+
+Other contributors:
+ Chetan Arakere Gowdru(chetan.arakere@altencalsoftlabs.com)
+
+Work Items
+----------
+#. Add code to stamp entities created by controller by key-value pair
+#. Add reconciliation
+#. Add unit test cases for new reconciliation code
+#. Scale test and measure the performance
+#. Add CSIT for reconciliation
+
+Dependencies
+============
+None
+
+Testing
+=======
+
+Unit Tests
+----------
+Appropriate UTs will be added for the new code coming in
+
+
+Integration Tests
+-----------------
+None
+
+
+CSIT
+----
+Necessary CSIT tests will be added
+
+We need to perform these tests for both single node and cluster cases
+
+
+Documentation Impact
+====================
+None.
+
+References
+==========
+[1] Fluorine DDF slides https://docs.google.com/presentation/d/1qLHdw3Hj5piv5eyQetzna-Gk-GndUa5C1pC-jIrnkPs/edit#slide=id.g35ab225711_0_69
+
+[2] OVSDB SB Reconciliation https://wiki.opendaylight.org/view/OVSDB_Integration:OVSDB_SB_Reconciliation
+
+[3] Bug 5951: Termination point config reconciliation https://trello.com/c/ISZ4MTNs/74-bug-5951-termination-point-config-reconciliation
+
+[4] Gerrit: Termination point config reconciliation https://git.opendaylight.org/gerrit/#/c/40506/
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Code Review / ovsdb.git / commitdiff