HWCloudEngine / hybrid_cloud

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[BGW HA] Implement "Post Failover Hook" in L2GW Agent #36

Open eshedg opened 8 years ago

eshedg commented 8 years ago

Overview of new functionality

Implement a hook point in the L2GW Agent that is called after L2GW Agent gets disconnected from an active OVSDB and selects an alternate OVSDB substitute (refer to #35 ). The hook point should be an external script/executable that is registered in the L2GW Agent configuration. By default, no script is registered.

Context of new functionality

When the L2GW Agent fails over to a substitute OVSDB/BGW it is possible that there are additional steps that need to be taken in order to complete the failover successfully. As an example, in the use case in mind we have a remote BGW sending traffic to the local one (which just crashed), and we need to switch the external IP of the local BGW to the substitute one, in order for it to receive the traffic from the remote BGW.