Thanks Yuepeng and Rui for creating this FLIP. +1 in general The idea is straight forward: best-effort gather all the slot requests and offered slots to form an overview before assigning slots, trying to balance the loads of task managers when assigning slots.
I have one comment regarding the configuration for ease of use: IIUC, this FLIP uses an existing config 'cluster.evenly-spread-out-slots' as the main switch of the new feature. That is, from user perspective, with this improvement, the 'cluster.evenly-spread-out-slots' feature not only balances the number of slots on task managers, but also balances the number of tasks. This is a behavior change anyway. Besides that, it also requires users to set 'slot.sharing-strategy' to 'TASK_BALANCED_PREFERRED' to balance the tasks in each slot. I think we can introduce a new config option `taskmanager.load-balance.mode`, which accepts "None"/"Slots"/"Tasks". `cluster.evenly-spread-out-slots` can be superseded by the "Slots" mode and get deprecated. In the future it can support more mode, e.g. "CpuCores", to work better for jobs with fine-grained resources. The proposed config option `slot.request.max-interval` then can be renamed to `taskmanager.load-balance.request-stablizing-timeout` to show its relation with the feature. The proposed `slot.sharing-strategy` is not needed, because the configured "Tasks" mode will do the work. WDYT? Thanks, Zhu Zhu Yuepeng Pan <panyuep...@apache.org> 于2023年9月25日周一 16:26写道： > Hi all, > > > I and Fan Rui(CC’ed) created the FLIP-370[1] to support balanced tasks > scheduling. > > > The current strategy of Flink to deploy tasks sometimes leads some > TMs(TaskManagers) to have more tasks while others have fewer tasks, > resulting in excessive resource utilization at some TMs that contain more > tasks and becoming a bottleneck for the entire job processing. Developing > strategies to achieve task load balancing for TMs and reducing job > bottlenecks becomes very meaningful. > > > The raw design and discussions could be found in the Flink JIRA[2] and > Google doc[3]. We really appreciate Zhu Zhu(CC’ed) for providing some > valuable help and suggestions in advance. > > > Please refer to the FLIP[1] document for more details about the proposed > design and implementation. We welcome any feedback and opinions on this > proposal. > > > [1] > https://cwiki.apache.org/confluence/display/FLINK/FLIP-370%3A+Support+Balanced+Tasks+Scheduling > > [2] https://issues.apache.org/jira/browse/FLINK-31757 > > [3] > https://docs.google.com/document/d/14WhrSNGBdcsRl3IK7CZO-RaZ5KXU2X1dWqxPEFr3iS8 > > > Best, > > Yuepeng Pan >
