The Virtual Package Trap: Debugging NVIDIA Driver/Library Mismatch in LXC Containers

Introduction

In the complex world of GPU-accelerated machine learning deployments, few errors are as simultaneously frustrating and instructive as the dreaded "Driver/library version mismatch." Message <msg id=6783> captures a pivotal moment in a multi-hour debugging session: the assistant has just discovered that an LXC container running inside a Proxmox VE host has NVIDIA userspace libraries from version 590.48, while the host kernel module is running version 580.126.09. The attempted fix — installing matching 580.x userspace libraries via apt — fails spectacularly, revealing a subtle dependency chain that exemplifies the hidden complexity of NVIDIA's Linux driver packaging.

Context: The Migration to kpro5

The broader session tells a story of infrastructure migration. The assistant had been running a Qwen3.6-27B model on a host called kpro6, which was being decommissioned. The model needed to be moved to kpro5 — a Proxmox VE host with 2× RTX A6000 GPUs (in addition to several RTX 3090s used by other VMs). The migration involved multiple steps: installing the NVIDIA driver 580.126.09 on the Proxmox host, unbinding the A6000s from vfio-pci (where they had been reserved for virtual machines), updating the LXC container configuration for CT129 to expose the correct device nodes, and starting the container.

When the assistant first started CT129 and ran nvidia-smi inside ([msg 6779]), it was greeted with:

Failed to initialize NVML: Driver/library version mismatch
NVML library version: 590.48

This error is a classic symptom of a version mismatch between the NVIDIA kernel module (loaded by the host kernel) and the userspace NVML library (used by tools like nvidia-smi). The container had been migrated from kpro6, where it had been configured with NVIDIA driver 590.48. The host kpro5 was running 580.126.09. The kernel module is shared with the host (LXC containers share the host kernel), but the userspace libraries are container-specific — hence the mismatch.

The assistant's first step was correct: purge the old 590.x libraries from inside the container ([msg 6781]). Then, it needed to install matching 580.x libraries. The question was: where to get them?

The Subject Message: A Failed Attempt

The subject message shows the assistant's first attempt at installing the matching userspace libraries:

580.126.09 is available from the Ubuntu archive. Let me install the exact matching version:

>

``bash ssh root@10.1.2.5 'pct exec 129 -- bash -c "DEBIAN_FRONTEND=noninteractive apt-get install -y libnvidia-compute-580=580.126.09-0ubuntu0.24.04.2 nvidia-utils-580=580.126.09-0ubuntu0.24.04.2 2>&1 | tail -10"' ``

>

Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:

>

The following packages have unmet dependencies: libnvidia-compute-580 : Depends: nvidia-kernel-common-580-580.126.09 nvidia-utils-580 : Depends: nvidia-kernel-common-580-580.126.09 E: Unable to correct problems, you have held broken packages.

The message is short but dense. It reveals the assistant's reasoning process and the assumptions that led to this failure.

Why This Message Was Written: The Reasoning and Motivation

The assistant wrote this message because it needed to resolve the driver/library version mismatch inside the LXC container. The motivation was straightforward: without matching userspace libraries, nvidia-smi and any GPU-accelerated workload (including the Qwen3.6-27B model) would fail inside the container.

The assistant had two options for installing the matching libraries:

  1. Copy the userspace libraries directly from the host's NVIDIA .run installer, which had already been extracted and installed on the Proxmox host.
  2. Install via apt from the Ubuntu package repository, using the exact version string to match the host kernel module. The assistant chose option 2, reasoning that the exact version 580.126.09-0ubuntu0.24.04.2 was available from the Ubuntu archive (as noted in the message's opening line). This was a reasonable choice: apt-based installation is cleaner, handles dependencies automatically, and integrates with the system's package management. The decision to pin the exact version (=580.126.09-0ubuntu0.24.04.2) was also deliberate. The host kernel module was version 580.126.09, and NVIDIA's userspace libraries must match the kernel module version exactly. Any version mismatch — even a minor one — would cause NVML initialization failures. The assistant was being precise to avoid exactly the problem it was trying to fix.

The Assumptions That Led to Failure

The failure reveals several assumptions the assistant made, all of which turned out to be incorrect:

Assumption 1: The package names libnvidia-compute-580 and nvidia-utils-580 would resolve to installable packages. This was partially correct — the packages exist in the repository. But the assistant assumed they could be installed independently of their dependency chain.

Assumption 2: The dependency nvidia-kernel-common-580-580.126.09 would be resolvable by apt. This was the critical mistake. The string nvidia-kernel-common-580-580.126.09 looks like a package name but is actually a virtual package — a package name that exists only as a dependency target, not as a real installable package. In NVIDIA's Debian packaging, nvidia-kernel-common-580 is the real package, and nvidia-kernel-common-580-580.126.09 is a virtual package provided by it. The version-specific virtual package name is a convention NVIDIA uses to allow multiple versions of the driver to coexist in the repository.

Assumption 3: Pinning the exact version would work. The assistant specified =580.126.09-0ubuntu0.24.04.2 for both packages, but this version string may not have existed in the repository for the dependency package. The error message "requested an impossible situation" suggests that the combination of package name and version didn't match any available package.

Assumption 4: The Ubuntu archive had the exact same version as the host's .run installer. The host's NVIDIA driver was installed from the official .run installer downloaded from nvidia.com. The Ubuntu archive packages are built from NVIDIA's Debian packages, which may have slightly different version strings or packaging conventions. The -0ubuntu0.24.04.2 suffix suggests an Ubuntu-specific rebuild, and the dependency chain may differ from the .run installer's layout.

Input Knowledge Required

To understand this message, the reader needs knowledge in several areas:

NVIDIA driver architecture: The NVIDIA GPU driver on Linux consists of two main components: the kernel module (nvidia.ko, nvidia-uvm.ko, etc.) which is loaded into the kernel, and the userspace libraries (libcuda.so, libnvidia-ml.so, etc.) which applications link against. The kernel module and userspace libraries must be from the same driver version. In an LXC container, the kernel module is shared with the host (containers share the host kernel), but the userspace libraries must be present inside the container.

LXC container configuration: LXC containers do not have their own kernel — they share the host kernel. GPU acceleration in LXC requires bind-mounting the NVIDIA device nodes (/dev/nvidia0, /dev/nvidiactl, /dev/nvidia-uvm, etc.) from the host into the container, and installing matching userspace libraries inside the container.

Debian/Ubuntu package management: Understanding virtual packages, dependency resolution, and the apt-get install workflow. The error message "held broken packages" is a specific apt error indicating that a dependency cannot be satisfied.

NVIDIA's Debian packaging conventions: NVIDIA uses a complex packaging scheme where nvidia-kernel-common-580 is the real package that provides the virtual package nvidia-kernel-common-580-580.126.09. This allows multiple driver versions to coexist in the repository without conflicting.

Output Knowledge Created

This message, even in its failure, creates valuable knowledge:

  1. The exact dependency chain for NVIDIA 580.x userspace packages on Ubuntu 24.04: libnvidia-compute-580 and nvidia-utils-580 both depend on nvidia-kernel-common-580-580.126.09, which is a virtual package.
  2. The specific error signature: The "held broken packages" error with the "requested an impossible situation" message is characteristic of attempting to install a package that depends on a virtual package that isn't provided by any real package in the configured repositories.
  3. A debugging trace: The message documents a failed approach, which is valuable for anyone else encountering the same issue. The subsequent messages ([msg 6784] and [msg 6785]) show the successful resolution: first checking apt-cache policy to understand the available versions, then installing nvidia-kernel-common-580 (the real package) first, followed by the compute libraries and utils.

The Thinking Process Visible in the Reasoning

The assistant's reasoning process is visible in the progression of messages leading up to and following this one. The thinking follows a clear pattern:

  1. Detect the problem ([msg 6779]): Run nvidia-smi inside the container, observe the "Driver/library version mismatch" error, note the specific library version (590.48).
  2. Diagnose the root cause ([msg 6780]): Check what NVIDIA packages are installed inside the container, confirm the 590.x libraries are present, identify the container's OS (Ubuntu 24.04).
  3. Remove the old libraries ([msg 6781]): Purge all 590.x packages to avoid conflicts.
  4. Identify the target version ([msg 6782]): Check what 580.x packages are available in the Ubuntu repos. Note that libnvidia-compute-580-server variants exist, but the assistant correctly avoids the -server variants (which are for headless/server environments and may lack certain libraries).
  5. Attempt the straightforward fix ([msg 6783], the subject message): Install the matching 580.x libraries with exact version pinning. This fails.
  6. Investigate the failure ([msg 6784]): Check apt-cache policy for the dependency package to understand why it can't be resolved.
  7. Find the workaround ([msg 6785]): Install nvidia-kernel-common-580 (the real package) first, then the compute libraries and utils. This succeeds.
  8. Verify the fix ([msg 6786]): Run nvidia-smi inside the container, confirm it now shows driver 580.126.09 and CUDA 13.0. This progression demonstrates a systematic debugging approach: detect, diagnose, remove obstacles, attempt fix, analyze failure, adjust approach, verify. The subject message is the "attempt fix" step that fails, but the failure is productive — it reveals information about the package dependency structure that the assistant couldn't have known beforehand.

The Broader Lesson: Virtual Packages as a Debugging Trap

The core insight from this message is that NVIDIA's Debian packaging uses virtual packages in a way that can trap even experienced engineers. The package name nvidia-kernel-common-580-580.126.09 looks like a real package — it follows the standard Debian naming convention of package-name-version. But it's actually a virtual package that is provided by nvidia-kernel-common-580. The version number embedded in the virtual package name is a mechanism to allow multiple driver versions to coexist, but it creates a confusing dependency chain.

When the assistant specified =580.126.09-0ubuntu0.24.04.2 for libnvidia-compute-580, apt tried to find a version of nvidia-kernel-common-580-580.126.09 that matched. But since that's a virtual package name (not a real package with versions), apt couldn't resolve it. The fix was to install the real package nvidia-kernel-common-580 first (without version pinning), which provided the virtual package, and then install the version-pinned compute libraries and utils.

This is a classic example of how the abstraction layer of package management can obscure the underlying reality. The virtual package mechanism is designed to solve a real problem (multiple driver versions), but it creates a debugging challenge when things go wrong.

Conclusion

Message <msg id=6783> captures a moment of productive failure in a complex infrastructure migration. The assistant's attempt to install matching NVIDIA userspace libraries via apt failed because of a subtle virtual package dependency, but the failure revealed the underlying package structure and led to a successful workaround in the following messages. The episode illustrates the hidden complexity of GPU-accelerated container deployments, where the clean abstraction of package management can sometimes obscure the messy reality of driver compatibility. For anyone deploying NVIDIA GPUs in LXC containers, understanding this virtual package trap is essential knowledge — and this message provides a perfect case study of how to recognize and resolve it.