Potential bug in vllm_<wx>.<yz>-py3 container images

I am running NGC containers on HPC GH200 platform.

First, I tried vllm_25.10-py3.sif but encountered an error when my python script attempted to import yaml module.

Then I switched to testing the latest NGC vllm image, i.e. vllm-26.03.post1-py3.sif, hoping it would have solved the issue but the same ModuleNotFound error appears:

BEGIN OUTPUT

<my_prompt> > apptainer run --nv --env PYTHONSTARTUP=“” containers/vllm_26.03.post1-py3.sif

INFO: gocryptfs not found, will not be able to use gocryptfs

==========

== vLLM ==

==========

NVIDIA Release 26.03.post1 (build 295860572)

vLLM Version 0.17.1+bd67d66a

Container image Copyright (c) 2025, NVIDIA CORPORATION & AFFILIATES. All rights reserved.

Various files include modifications (c) NVIDIA CORPORATION & AFFILIATES. All rights reserved.

GOVERNING TERMS: The software and materials are governed by the NVIDIA Software License Agreement

(found at https://www.nvidia.com/en-us/agreements/enterprise-software/nvidia-software-license-agreement/)

and the Product-Specific Terms for NVIDIA AI Products

(found at https://www.nvidia.com/en-us/agreements/enterprise-software/product-specific-terms-for-ai-products/).

NOTE: CUDA Forward Compatibility mode ENABLED.

Using CUDA 13.2 driver version 595.45.04 with kernel driver version 580.65.06.

See CUDA Compatibility — CUDA Compatibility for details.

Apptainer> python

Python 3.12.3 (main, Mar 3 2026, 12:15:18) [GCC 13.3.0] on linux

Type “help”, “copyright”, “credits” or “license” for more information.

>>> import yaml

Traceback (most recent call last):

File “”, line 1, in

File “/cluster/home/dragana/.local/lib/python3.12/site-packages/yaml/_init_.py”, line 2, in

from .error import \*

ModuleNotFoundError: No module named ‘yaml.error’

>>>

END OUTPUT

Have I forgotten to do some additional setup? Or is it a bug in how python’s site-packages?

Thank you in advance!

This seems to be an incomplete installation of yaml Python package. What would be the recommended way to install / upgrade yaml package within the NGC vllm_xx-py3.sif image?

This proved to be caused by leaking home environment. The issue is RESOLVED by running the container image with ‘–no-home’ option: apptainer run --nv --no-home vllm_25.10-py3.sif.