SeaStar Server configuration introduction

[Gforky]

URL(s) with the issue:

https://deeprec.readthedocs.io/zh/latest/StarServer.html#estimator

Description of issue (what needs changing):

Clear description

Try to run PS distributed training with SeaStar servers according to the documentation above, but encounter an error: Load endpoint map from .endpoint_map failed. Confused about how to generate the endpoint_map, hope for more detailed illustrations in the documentation.

[shanshanpt]

We will provide much more details documents later. And the format of .endpoint_map is as follows: 127.0.0.1:10000=127.0.0.1:10001 127.0.0.1:22222=127.0.0.1:22223 127.0.0.1:33333=127.0.0.1:33334 ...

you should reserve two port for woker and ps, for example 127.0.0.1:10000 and 127.0.0.1:10001, one for grpc and the other one for seastar. So you can generate the file according the format above.