Safe Mounting of /dev/gdrdrv in a kubernetes environment - HostPath appears to fail

[hassanbabaie]

Hi @pakmarkthub, sorry for the tag but it's related to this one:

https://github.com/NVIDIA/gdrcopy/issues/278#issuecomment-1736701644

Is there a recommend what to enable gdrcopy within a Kubernetes environment, I'm trying to use the HostPath method as a file but this looks to be incorrect.

  host-gdrcopy:
    Type:          HostPath (bare host directory volume)
    Path:          /dev/gdrdrv
    HostPathType:  File

I was hoping I'm not the first person to try and do this?

Thanks

[pakmarkthub]

Hi @hassanbabaie, I am not familiar with Kubernetes. Let me find out if someone might know the answer.

[hassanbabaie]

Thanks @pakmarkthub , I'm hoping there is a documented way as this should be something that I would expected is a growing scenario.

[cdesiniotis]

Hi @hassanbabaie, mounting the device node with a hostPath volume will only work if you run your pod as privileged. Otherwise, the container process won't have write permissions on the device node.

We are working on adding gdrcopy support to NVIDIA Container Runtime (see https://gitlab.com/nvidia/container-toolkit/container-toolkit/-/merge_requests/530), and it should make it into the next release. With this feature, you can inject /dev/gdrdrv into your container by setting the NVIDIA_GDRCOPY=enabled environment variable in your container spec. It will not be required to run your pod as privileged.

cc @elezar

[hassanbabaie]

Thanks this is great news @cdesiniotis, yes this will be much better as leveraging privileged is not desired.

If possible can you post here when it's released we can then look to try it out

[hassanbabaie]

Hi @cdesiniotis I can't seem to access https://gitlab.com/nvidia/container-toolkit/container-toolkit/-/merge_requests/530

Do you happen to have any update on this?

[hassanbabaie]

It looks like this is now covered in v1.15.0-rc.2 and it's worked it's way through to v1.15.0-rc.4,

Do we happen to know the estimated release timeline?

[pakmarkthub]

Hi @hassanbabaie,

FYI, we have released a gdrdrv container image on NGC: https://catalog.ngc.nvidia.com/orgs/nvidia/teams/cloud-native/containers/gdrdrv. Running that image will automatically compile and install the gdrdrv driver on your system. It will also expose /dev/gdrdrv. However, you still need to attach that path to your application containers manually.

It looks like this is now covered in v1.15.0-rc.2 and it's worked it's way through to v1.15.0-rc.4,

Do we happen to know the estimated release timeline?

@cdesiniotis Do you have anything that you can share regarding gdrdrv support in NVIDIA Container Runtime?

[cdesiniotis]

@hassanbabaie apologies for the delayed response. NVIDIA Container Toolkit 1.15.0 has been released. You can set NVIDIA_GDRCOPY=enabled environment variable in your container spec, and the /dev/gdrdrv device node should be made available to your container.

[stefanomaxenti]

I tried to deploy this on OpenShift, and at the beginning I was not able to have the /dev/gdrdrv available in the (privileged) container. I found the logs of the gdrcopy installer:

# oc logs  -n nvidia-gpu-operator nvidia-driver-daemonset-414.92.202401121330-0-cmhxv -c nvidia-gdrcopy-ctr

Running gdrcopy-ctr-run-with-dtk
+ [[ ! -f /mnt/shared-nvidia-driver-toolkit/dir_prepared ]]
+ cp -r /usr/local/gdrcopy /mnt/shared-nvidia-driver-toolkit/
+ set +x
Mon May 13 20:45:15 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to start ...
Mon May 13 20:45:30 UTC 2024 openshift-driver-toolkit-ctr started.
Mon May 13 20:45:30 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:45:45 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:46:00 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:46:15 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:46:30 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:46:45 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:47:00 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:47:15 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
Mon May 13 20:47:30 UTC 2024 Waiting for openshift-driver-toolkit-ctr container to build the gdrdrv.ko kernel object ...
+ SRC_SHARED=/mnt/shared-nvidia-driver-toolkit/gdrcopy/src/gdrdrv
+ '[' -d /run/nvidia/driver/usr/src ']'
Waiting for nvidia driver to be loaded and rootfs to be mounted ...
+ echo 'Waiting for nvidia driver to be loaded and rootfs to be mounted ...'
+ sleep 5
+ '[' -d /run/nvidia/driver/usr/src ']'
+ lsmod
+ grep nvidia
nvidia_peermem         20480  0
nvidia_modeset       1499136  0
nvidia_uvm           6455296  4
nvidia               8626176  17 nvidia_uvm,nvidia_peermem,nvidia_modeset
ib_core               491520  9 rdma_cm,ib_ipoib,nvidia_peermem,iw_cm,ib_umad,rdma_ucm,ib_uverbs,mlx5_ib,ib_cm
drm                   581632  5 drm_kms_helper,ast,drm_shmem_helper,nvidia
+ cp -rv /mnt/shared-nvidia-driver-toolkit/gdrcopy/src/gdrdrv/gdrdrv.ko /usr/local/gdrcopy/src/gdrdrv/gdrdrv.ko
'/mnt/shared-nvidia-driver-toolkit/gdrcopy/src/gdrdrv/gdrdrv.ko' -> '/usr/local/gdrcopy/src/gdrdrv/gdrdrv.ko'
Loading gdrdrv kernel module
+ echo 'Loading gdrdrv kernel module'
+ _load_module
+ cd /usr/local/gdrcopy
+ insmod src/gdrdrv/gdrdrv.ko dbg_enabled=0 info_enabled=0 use_persistent_mapping=0
Creating gdrdrv device node
+ echo 'Creating gdrdrv device node'
+ _create_device_node
++ fgrep gdrdrv /proc/devices
++ cut -b 1-4
+ major='505 '
INFO: driver major is 505
+ echo 'INFO: driver major is 505 '
+ mknod /run/nvidia/driver/dev/gdrdrv c 505 0
+ chmod a+w+r /run/nvidia/driver/dev/gdrdrv
Done, now waiting for signal
+ echo 'Done, now waiting for signal'
+ trap 'echo '\''Caught signal'\''; _shutdown && { kill 696326; exit 0; }' HUP INT QUIT PIPE TERM
+ trap - EXIT
+ true
+ wait 696326
+ sleep infinity

and noticed that gdrcopy was not installed in /dev/gdrdrv but in /run/nvidia/driver/dev/gdrdrv. Therefore, I had to modify the volume mounts in the pod as following:

    - mountPath: /dev/gdrdrv
      name: gdrdrv
  - name: gdrdrv
    hostPath:
     path: /run/nvidia/driver/dev/gdrdrv

I don't know if this is the right way to do it but it works.

[cdesiniotis]

@stefanomaxenti yes, if you are leveraging GPU Operator to install the GDRCopy driver, the device node will be present at /run/nvidia/driver/dev/gdrdrv on the host.

[stefanomaxenti]

While everything works fine on a privilged container, I am unable to use the env. variable NVIDIA_GDRCOPY=enabled inside a non-privileged pod using the NVIDIA GPU Operator. Without hostPath and with the variable, gdrdrv is not visible. But with hostPath, it is not usable since it requires R/W permission and the pod is not privileged.

I think it is related to this issue https://github.com/NVIDIA/gpu-operator/issues/713 on the operator side closed some days after releasing 24.3.0. I will try when it is avaiable to deploy.

Do you maybe have any other ideas to why GDRCopy is not working as expected in this setup? Thank you.

[cdesiniotis]

@stefanomaxenti ah I see you are on OpenShift. Unfortunately the NVIDIA_GDRCOPY=enabled envvar will have no effect on OpenShift today because we are not using NVIDIA Container Runtime there, and instead, are using an OCI hook -- so the component which parses this environment variable and adds the gdrdrv character device to the container never gets invoked. Like you observed, only a privileged container which has the /dev/gdrdrv hostPath mounted will work on OpenShift. We are looking to remove this limitation in a future release.