12630: request both 'compute' and 'utility' nvidia capabilities

Add note about capabilities.

Arvados-DCO-1.1-Signed-off-by: Peter Amstutz <peter.amstutz@curii.com>

diff --git a/lib/crunchrun/docker.go b/lib/crunchrun/docker.go
index f437d6a0c39d6c25d42fec9b5d312ca73a01d5d9..ea9d448215cd1f700bce3bb2b675442c3fc6d231 100644 (file)
--- a/lib/crunchrun/docker.go
+++ b/lib/crunchrun/docker.go
@@ -119,14 +119,29 @@ func (e *dockerExecutor) config(spec containerSpec) (dockercontainer.Config, doc
                if len(deviceIds) > 0 {
                        // Docker won't accept both non-empty
                        // DeviceIDs and a non-zero Count
+                       //
+                       // (it turns out "Count" is a dumb fallback
+                       // that just allocates device 0, 1, 2, ...,
+                       // Count-1)
                        deviceCount = 0
                }
 
+               // Capabilities are confusing.  The driver has generic
+               // capabilities "gpu" and "nvidia" but then there's
+               // additional capabilities "compute" and "utility"
+               // that are passed to nvidia-container-cli.
+               //
+               // "compute" means include the CUDA libraries and
+               // "utility" means include the CUDA utility programs
+               // (like nvidia-smi).
+               //
+               // https://github.com/moby/moby/blob/7b9275c0da707b030e62c96b679a976f31f929d3/daemon/nvidia_linux.go#L37
+               // https://github.com/containerd/containerd/blob/main/contrib/nvidia/nvidia.go
                hostCfg.Resources.DeviceRequests = append(hostCfg.Resources.DeviceRequests, dockercontainer.DeviceRequest{
                        Driver:       "nvidia",
                        Count:        deviceCount,
                        DeviceIDs:    deviceIds,
-                       Capabilities: [][]string{[]string{"gpu", "nvidia"}},
+                       Capabilities: [][]string{[]string{"gpu", "nvidia", "compute", "utility"}},
                })
        }
        for path, mount := range spec.BindMounts {