Hi,
Currently, Flink does not support automatic scaling of the YARN containers.
Adding an API for manually starting and stopping containers is something we can do very easily, something dynamic is a bit harder.
The feature is something I was always interested to work on, but nobody really asked for it. But it seems that more and more people are asking for it.
If this is a requirement for you to use Flink, I'm certainly willing to add the feature into Flink.
Best,
Robert