Horovod Elasticity Adjust number of Workers in RunTime
I have been using Horovod using both TensorFlow and PyTorch in docker, every thing works fine under a fixed number of containers as explained in Horovod docker

I have checked the Horovod Elastic Demos Horovod examples but they doesn't show how to change the number of workers in runtime.

What I need is to know how to change the number of workers up or down by runtime?

What you need for that is a Docker-specific host discovery that tells Elastic Horovod about all available containers. A generic way to do this is by using horovodrun and providing a host discovery script via --host-discovery-script. When invoked, the script returns a list of available hosts. See the Running with horovodrun section of the Elastic Horovod documentation.

In the near future there will be service provider specific host discoveries built into Horovod so users do not need to implement scripts for common providers.
