[Doc] update multinode doc

[MengqingCao]

Update multinode doc
fix #167 #168

[wangxiyuan]

I just notice that this env is set in platform. https://github.com/vllm-project/vllm-ascend/blob/main/vllm_ascend/platform.py#L36

So maybe it should be set during worker initialization as well?

[ApsarasX]

LGTM

[MengqingCao]

So maybe it should be set during worker initialization as well?

I test locally when we set RAY_EXPERIMENTAL_NOSET_ASCEND_RT_VISIBLE_DEVICES to 1 in the init of NPUWorker, but it doesn't work.

I think this is quite similar to #92, we need to make sure that every ray task sets this environment variable, and this should be done before the actor is created.
In a multi-node environment, perhaps we can only put it here and let the user specify it manually now. Or we could add this to ray_patch if #92 is merged

[wangxiyuan]

@MengqingCao how about in register func?

[MengqingCao]

@MengqingCao how about in register func?

It works for single-node.

but I think it may not work for multi-node, because setting it in register is quite same as setting it in Platform, the way we already implemented but not work.