How to debug torchserve pip install?

We’re trying to use torchserve (via KFServing).

We prepared .mar with our model and requirements.txt (most notable dependency is transformers)

When we try to run in torchserve logs I see a line “Custom pip package installation failed for ”

When connect to container and execute “pip install -r requirements.txt” all dependencies install just fine.

Question: how do I get more detailed error about pip install from torchserve?