Re: Flink Job claster scalability

2020-01-10 Thread Yangze Guo
Hi KristoffSC As Zhu said, Flink enables slot sharing[1] by default. This feature is nothing to do with the resource of your cluster. The benefit of this feature is written in [1] as well. I mean, it will not detect how many slots in your cluster and adjust its behavior toward this number. If you

Re: Flink Job claster scalability

2020-01-10 Thread KristoffSC
Hi Zhu Zhu, well In my last test I did not change the job config, so I did not change the parallelism level of any operator and I did not change policy regarding slot sharing (it stays as default one). Operator Chaining is set to true without any extra actions like "start new chain, disable chain

Re: Flink Job claster scalability

2020-01-09 Thread Zhu Zhu
Hi KristoffSC, Did you increase the parallelism of the vertex that has the largest parallelism? Or did you explicitly set tasks to be in different slot sharing group? With the default slot sharing, the number of slots required/used equals to the max parallelism of a JobVertex, which is 6 in your

Re: Flink Job claster scalability

2020-01-09 Thread KristoffSC
Thank you David and Zhu Zhu, this helps a lot. I have follow up questions though. Having this /"Instead the Job must be stopped via a savepoint and restarted with a new parallelism"/ and slot sharing [1] feature, I got the impression that if I would start my cluster with more than 6 task slots,

Re: Flink Job claster scalability

2020-01-09 Thread David Maddison
Hi KristoffSC, As Zhu Zhu explained, Flink does not currently auto-scale a Job as new resources become available. Instead the Job must be stopped via a savepoint and restarted with a new parallelism (the old rescale CLI experiment use to perform this). Making Flink reactive to new resources and

Re: Flink Job claster scalability

2020-01-08 Thread Zhu Zhu
Hi KristoffSC, Each task needs a slot to run. However, Flink enables slot sharing[1] by default so that one slot can host one parallel instance of each task in a job. That's why your job can start with 6 slots. However, different parallel instances of the same task cannot share a slot. That's why