Hi All, We are currently working on introducing $subject [1]. Please find below a high level description of the approach.
An extension point (HaStrategy) will be introduced, allowing straightforward introduction of different implementations of identification of the active node, where the only requirements would be that these approaches extend the common class and invoke particular methods when the node state changes. The broker-core and broker-transport (broker-amqp) modules would introduce listeners to receive notifications of node states changes (active/passive), and change behaviour accordingly. ​ *Configuration* The HA related configuration would be specified in the broker.yaml file including whether HA is enabled and the HA strategy to use. haConfig: enabled: true strategy: org.wso2.broker.coordination.rdbms.RdbmsHaStrategy The basic/initial HA strategy implementation will be the RdbmsHaStrategy based on the RDBMS based coordinator election approach previously introduced for MB 3.2.0. [2, 3]. ​If HA enabled is set to true but no strategy is specified, the RdbmsHaStrategy will be used. *RDBMS Coordinator Election based HA Strategy (RdbmsHaStrategy)* The RDBMS based coordinator election algorithm would be extended to provide HA support, by specifying the node elected as coordinator to always be the active node, while the other node(s) will be considered passive. The RDBMS coordinator election based approach, which would also be the default HA strategy, would require the nodes in the HA group to share the same database. All MB nodes pointing to this shared database will be considered as MBs belonging to the same group, and at any given point only one of the nodes will be considered active. Feedback on the approach would be highly appreciated. [1] https://github.com/wso2/message- <https://github.com/wso2/message-broker/issues/87>*when*broker/issues/87 <https://github.com/wso2/message-broker/issues/87> [2] Mail: "[Architecture] RDBMS based coordinator election algorithm for MB" [3] https://github.com/wso2/andes/pullwhen/668 <https://github.com/wso2/andes/pull/668> Thank you, Maryam ​ -- *Maryam Ziyad Mohamed* Software Engineer | WSO2 [image: http://wso2.com/signature] <http://wso2.com/signature>
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