Update torchrun and TorchElastic to take optional `local_addr` param to allow skip local IP lookup if specified (#88922)
Summary:
Update dynamic renderzvous nodes to use rendezvous hostname if provided.
For PR: https://github.com/pytorch/pytorch/issues/85300
Before:
For dynamic renderzvous, it always grab the `fqdn` from socket for each node even if user specified the address.
For example,
https://github.com/pytorch/pytorch/blob/master/torch/distributed/elastic/rendezvous/dynamic_rendezvous.py#L248-L256
```
return _NodeDesc(socket.getfqdn(), os.getpid(), local_id)
```
Now:
If user specifies the hostname, each node will respect the given hostname.
For example, `socket.getfqdn(<hostname>) `
Test Plan: Unit tests.
Differential Revision: D41204028
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88922
Approved by: https://github.com/d4l3k
