fix(gpu): add Tegra/Jetson GPU support by elezar · Pull Request #625 · NVIDIA/OpenShell

elezar · 2026-03-26T13:56:58Z

Summary

Adds GPU support for NVIDIA Tegra/Jetson platforms by bind-mounting the
host-files configuration directory, updating the device plugin image, and
preserving CDI-injected GIDs across privilege drop.

Related Issue

Part of #398 (CDI injection). Depends on #568 (Tegra system support). Should be merged after #495 and #503.

Upstream PRs:

nvidia-container-toolkit: fix: Additional GIDs are dropped due to file mode mask nvidia-container-toolkit#1745
k8s-device-plugin: Fix CDI spec generation to respect driver root for Tegra CSV files k8s-device-plugin#1675

Changes

Bind-mount /etc/nvidia-container-runtime/host-files-for-container.d (read-only) into the gateway container when present, so the nvidia runtime inside k3s applies the same host-file injection config as the host — required for Jetson/Tegra CDI spec generation
Pin k8s-device-plugin to an image that supports host-files bind-mounts and generates additionalGids in the CDI spec (GID 44 / video, required for /dev/nvmap access on Tegra)
Preserve CDI-injected supplemental GIDs across initgroups() during privilege drop, so exec'd processes retain access to GPU devices
Fall back to /usr/sbin/nvidia-smi in the GPU e2e test for Tegra systems where nvidia-smi is not on the default PATH

Testing

mise run pre-commit passes
Unit tests added/updated
E2E tests added/updated (if applicable)

Checklist

Follows Conventional Commits
Commits are signed off (DCO)
Architecture docs updated (if applicable)

Bind-mount /etc/nvidia-container-runtime/host-files-for-container.d (read-only) into the gateway container when it exists, so the nvidia runtime running inside k3s can apply the same host-file injection config as on the host — required for Jetson/Tegra platforms. Signed-off-by: Evan Lezar <elezar@nvidia.com>

Use ghcr.io/nvidia/k8s-device-plugin:2ab68c16 which includes support for mounting /etc/nvidia-container-runtime/host-files-for-container.d into the device plugin pod, required for correct CDI spec generation on Tegra-based systems. Also included is an nvcdi API bump that ensures that additional GIDs are included in the generated CDI spec. Signed-off-by: Evan Lezar <elezar@nvidia.com>

initgroups(3) replaces all supplemental groups with the user's entries from /etc/group, discarding GIDs injected by the container runtime via CDI (e.g. GID 44/video needed for /dev/nvmap on Tegra). Snapshot the container-level GIDs before initgroups runs and merge them back afterwards, excluding GID 0 (root) to avoid privilege retention. Signed-off-by: Evan Lezar <elezar@nvidia.com>

On Jetson/Tegra platforms nvidia-smi is installed at /usr/sbin/nvidia-smi rather than /usr/bin/nvidia-smi and may not be on PATH inside the sandbox. Fall back to the full path when the bare command is not found. Signed-off-by: Evan Lezar <elezar@nvidia.com>

elezar · 2026-03-26T13:58:13Z

cc @johnnynunez

johnnynunez · 2026-03-26T14:52:25Z

LGTM @elezar
ready to merge @johntmyers

elezar · 2026-03-27T07:15:59Z

This was only tested in conjunction with #495 and #503. Once those are in, there should be no reason to not get this in too.

johnnynunez · 2026-03-27T07:26:08Z

This

Yes, i know. I was tracking it. And tested

pimlock · 2026-04-01T18:48:24Z

I dug into the GID-preservation change here and I think PR #710 may make it unnecessary.

What I verified locally:

Inside a running sandbox, the GPU device nodes are owned by sandbox:sandbox after supervisor setup.
The corresponding host and k3s-container device nodes remain root:root 666, so the sandbox-side chown() does not appear to mutate the host devices.
That suggests these are container-local CDI-created device nodes, not direct host bind mounts.

If that holds generally, then once #710 adds the needed GPU device paths to filesystem.read_write, prepare_filesystem() will chown(path, uid, gid) before privilege drop and DAC access should come from ownership rather than from preserving CDI-injected supplemental groups.

So I think we should re-check whether the drop_privileges() GID merge is still needed after #710 lands. It may be removable if all required GPU paths (including Tegra-specific ones like /dev/nvmap if applicable) are present and successfully chowned.

pimlock · 2026-04-01T19:39:33Z

Follow-up: I removed the checked-in custom ghcr.io/nvidia/k8s-device-plugin:2ab68c16 image override from this branch.

If someone still needs that image on a live gateway for testing, they can patch the running cluster in place:

openshell doctor exec -- kubectl -n kube-system patch helmchart nvidia-device-plugin --type merge -p '{
  "spec": {
    "valuesContent": "image:\n  repository: ghcr.io/nvidia/k8s-device-plugin\n  tag: \"2ab68c16\"\nruntimeClassName: nvidia\ndeviceListStrategy: cdi-cri\ndeviceIDStrategy: index\ncdi:\n  nvidiaHookPath: /usr/bin/nvidia-cdi-hook\nnvidiaDriverRoot: \"/\"\ngfd:\n  enabled: false\nnfd:\n  enabled: false\naffinity: null\n"
  }
}'
openshell doctor exec -- kubectl -n nvidia-device-plugin rollout status ds/nvidia-device-plugin
openshell doctor exec -- kubectl -n nvidia-device-plugin get ds nvidia-device-plugin -o jsonpath='{.spec.template.spec.containers[0].image}{"\\n"}'

That only affects the running gateway. Recreating the gateway reapplies the checked-in manifest.

pimlock · 2026-04-01T20:44:23Z

Once the #710 is reviewed and merged, I will add it to here and test it again. I'm getting a lease on colossus for a Jetson-based system.

It's very likely there will be some updates to the policy required, with the #677 now merged and before that, in many contexts landlock policies were not correctly applied.

This reverts commit 730d104.

pimlock · 2026-04-07T00:09:34Z

crates/openshell-bootstrap/src/docker.rs

+    const HOST_FILES_DIR: &str = "/etc/nvidia-container-runtime/host-files-for-container.d";
+    if std::path::Path::new(HOST_FILES_DIR).is_dir() {
+        let mut binds = host_config.binds.take().unwrap_or_default();
+        binds.push(format!("{HOST_FILES_DIR}:{HOST_FILES_DIR}:ro"));
+        host_config.binds = Some(binds);
+    }


For the context, without this mount the failure is:

The error says: CDI --device-list-strategy options are only supported on NVML-based systems — the device plugin can't detect the GPU via NVML (since Tegra uses a different driver model), so it refuses to start with CDI mode.

The bind mount is needed. Without it, the NVIDIA toolkit inside the gateway can't recognize this as a Tegra platform with GPU capabilities, CDI spec generation fails, and the device plugin crashes.

- Bump nvidia-container-toolkit from 1.18.2 to 1.19.0 to support the -host-cuda-version flag used by newer CDI spec generation. - Replace local filesystem check for host-files-for-container.d with Docker API kernel version detection (contains "tegra"). This fixes remote SSH deploys where the CLI machine may not have the directory. - Only perform the Tegra check when GPU devices are requested.

pimlock · 2026-04-07T01:00:53Z

Testing on Jetson Thor (NVIDIA Thor GPU, driver 580.00, CUDA 13.0)

Validated the following on a physical Jetson Thor device:

Container Toolkit bump (1.18.2 → 1.19.0)

Required. The custom device plugin (k8s-device-plugin PR #1675) generates CDI specs with the --host-cuda-version flag. Toolkit 1.18.2's nvidia-cdi-hook doesn't recognize this flag, causing RunContainerError on GPU sandbox pods. 1.19.0 supports it.

`host-files-for-container.d` bind mount

Required. Without it, the device plugin cannot discover Tegra GPU devices and fails with "CDI options are only supported on NVML-based systems". The CSVs (devices.csv, drivers.csv) are inputs to CDI spec generation — they tell the toolkit which Tegra-specific device nodes and host libraries to inject.
Fixed the detection: replaced local Path::is_dir() check with docker.info() kernel version detection (contains("tegra")). The previous approach broke remote SSH deploys (CLI machine doesn't have the directory). Now gated on !device_ids.is_empty() so it's only checked for GPU gateways.

Custom device plugin (k8s-device-plugin PR #1675)

Required. Stock device plugin 0.18.2 can detect the Tegra platform and register with kubelet, but generates a nearly empty CDI spec (no device nodes, no library mounts). The custom build with driver-root-aware CSV resolution is needed for functional GPU access.
Tested: stock plugin → torch.cuda.is_available() returns False (no /dev/nvidia* in sandbox). Custom plugin → full PyTorch CUDA 13.0 matrix multiply succeeds on Thor.

GID merge in `process.rs`

Not needed today but harmless. CDI spec is v0.5.0 (no additionalGids support) and all device nodes are 0666. The code would become relevant with CDI v0.7.0+ and toolkit 1.19.1+ (nvidia-container-toolkit PR #1745).

Other findings

br_netfilter kernel module must be loaded on Tegra for k3s DNS/service networking. Without it, pods can't reach CoreDNS via ClusterIP. Good candidate for a pre-flight check.
Device plugin warnings about missing V4L2/GStreamer/legacy-tegra files are harmless — they're display/video codec libraries, not needed for CUDA compute.

…ID preservation - Log when Tegra platform is detected and host-files bind mount is added, including the kernel version from the Docker daemon. - Extract CDI GID snapshot logic into `snapshot_cdi_gids()` function that only activates when GPU devices are present (/dev/nvidiactl exists). - Log preserved CDI-injected GIDs when they are restored after initgroups. - Fix cargo fmt formatting issue in docker.rs.

elezar added 4 commits March 26, 2026 14:44

elezar self-assigned this Mar 26, 2026

elezar marked this pull request as ready for review March 27, 2026 07:16

elezar requested a review from a team as a code owner March 27, 2026 07:16

pimlock added 2 commits April 1, 2026 11:55

Merge remote-tracking branch 'origin/main' into fix/tegra-gpu-support

2c06aad

fix(gpu): gate Tegra-specific runtime adjustments

730d104

pimlock added 2 commits April 2, 2026 00:24

Revert "fix(gpu): gate Tegra-specific runtime adjustments"

ccb6654

This reverts commit 730d104.

Merge remote-tracking branch 'origin/main' into fix/tegra-gpu-support

4eccf31

pimlock added the test:e2e Requires end-to-end coverage label Apr 2, 2026

pimlock reviewed Apr 7, 2026

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fix(gpu): add Tegra/Jetson GPU support#625

fix(gpu): add Tegra/Jetson GPU support#625
elezar wants to merge 10 commits intomainfrom
fix/tegra-gpu-support

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Summary

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Testing on Jetson Thor (NVIDIA Thor GPU, driver 580.00, CUDA 13.0)

Container Toolkit bump (1.18.2 → 1.19.0)

host-files-for-container.d bind mount

Custom device plugin (k8s-device-plugin PR #1675)

GID merge in process.rs

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elezar commented Mar 26, 2026 •

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`host-files-for-container.d` bind mount

GID merge in `process.rs`