Using conda pytorch. Running my code with python -m torch.distributed.launch --use_env --nproc_per_node 2 on a single node with 2 GPUs.
In my code I took care of the logging so that it is only logged by the main process and it used to work for previous PyTorch versions. However, in PyTorch 1.8.0, logging is done with an additional, default-style, logger, both for the main process and the other(s).
This is how it looks like in PyTorch 1.7.0:
[2021-03-08 21:03:51,597][midaGAN.utils.environment][INFO] - PyTorch version: 1.7.0
[2021-03-08 21:03:51,598][midaGAN.utils.environment][INFO] - CUDA 10.2 - cuDNN 7605
[2021-03-08 21:03:51,598][midaGAN.utils.environment][INFO] - Global rank: 0.
[2021-03-08 21:03:51,598][midaGAN.utils.environment][INFO] - Local rank: 0.

And this is for PyTorch 1.8.0. We can see the same messages of the main process being logged twice, once with the logger i defined and once with some default-styled logger that does not occur in 1.7.0.
That same default logger also logs the other (non-main) process.
INFO:midaGAN.utils.environment:PyTorch version: 1.8.0
[2021-03-08 21:05:36,843][midaGAN.utils.environment][INFO] - PyTorch version: 1.8.0
INFO:midaGAN.utils.environment:CUDA 10.2 - cuDNN 7605
[2021-03-08 21:05:36,843][midaGAN.utils.environment][INFO] - CUDA 10.2 - cuDNN 7605
INFO:midaGAN.utils.environment:Global rank: 0.
[2021-03-08 21:05:36,844][midaGAN.utils.environment][INFO] - Global rank: 0.
INFO:midaGAN.utils.environment:Local rank: 0.
[2021-03-08 21:05:36,844][midaGAN.utils.environment][INFO] - Local rank: 0.
.
.
.
# NOTE: the default logger is not enabled for other processes, but PyTorch is somehow logging it with a default-style logger
INFO:midaGAN.utils.environment:PyTorch version: 1.8.0
INFO:midaGAN.utils.environment:CUDA 10.2 - cuDNN 7605
INFO:midaGAN.utils.environment:Global rank: 1.
INFO:midaGAN.utils.environment:Local rank: 1.

Am I missing something?