akshaychitneni opened a new pull request, #1568: URL: https://github.com/apache/datafusion-ballista/pull/1568
Add SchedulerConfig::event_listeners to observe executor join/leave without modifying core. Notifies on both pull-based and push-based registration, and on executor loss. For example, [Kubeflow Data Cache](https://www.kubeflow.org/docs/components/trainer/user-guides/data-cache/) when implemented as a ballista extension, it can use this to redistribute cached dataset shards when executors join or leave the cluster on kubernetes # Which issue does this PR close? <!-- We generally require a GitHub issue to be filed for all bug fixes and enhancements and this helps us generate change logs for our releases. You can link an issue to this PR using the GitHub syntax. For example `Closes #123` indicates that this PR will close issue #123. --> Closes #. # Rationale for this change <!-- Why are you proposing this change? If this is already explained clearly in the issue then this section is not needed. Explaining clearly why changes are proposed helps reviewers understand your changes and offer better suggestions for fixes. --> There is currently no way for external plugins to observe executor join/leave events. Plugins that manage distributed state (e.g., in-memory data caches) need to react when executors are added or removed to rebalance data. This change adds a minimal, non-breaking extension point for executor lifecycle observation. # What changes are included in this PR? <!-- There is no need to duplicate the description in the issue here but it is sometimes worth providing a summary of the individual changes in this PR. --> New SchedulerEventListener trait and event_listeners field on SchedulerConfig with builder method. Listeners are notified on executor registration (pull + push), removal, and loss. Updated custom-scheduler example with usage. # Are there any user-facing changes? <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. --> New optional field on SchedulerConfig. Default is empty — no behavior change for existing users. No breaking changes to public APIs. <!-- If there are any breaking changes to public APIs, please add the `api change` label. --> -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
