OpenShiftP-281: refactor to account for the situation where nx-gzip is not present on system

Signed-off-by: Paul Bastide <[email protected]>

Author: prb112

cmd/power-dra-kubeletplugin/discovery.go

@@ -10,18 +10,24 @@ import (
 	"math/rand"
 	"os"
 
+	"github.com/google/uuid"
 	resourceapi "k8s.io/api/resource/v1beta1"
 	"k8s.io/apimachinery/pkg/api/resource"
+	"k8s.io/klog/v2"
 	"k8s.io/utils/ptr"
-
-	"github.com/google/uuid"
 )
 
+const NXGZIPCAPS = "/host-sys/devices/vio/ibm,compression-v1/nx_gzip_caps"
+
 func enumerateAllPossibleDevices(numNx int) (AllocatableDevices, error) {
 	seed := os.Getenv("NODE_NAME")
 	uuids := generateUUIDs(seed, numNx)
-
 	alldevices := make(AllocatableDevices)
+	if !existsNxGzip() {
+		// If nx-gzip doesn't exist, then don't return any devices.
+		return alldevices, nil
+	}
+
 	for i, uuid := range uuids {
 		device := resourceapi.Device{
 			Name: fmt.Sprintf("nx-%d", i),
@@ -73,3 +79,13 @@ func hash(s string) int64 {
 	}
 	return h
 }
+
+// Detect NXGZIPCAPS exists
+func existsNxGzip() bool {
+	_, err := os.Stat(NXGZIPCAPS)
+	if err != nil {
+		klog.V(5).ErrorS(err, "Failed to detect Nest Accelerator nx-gzip feature")
+		return false
+	}
+	return true
+}

deployments/helm/power-dra-driver/templates/kubeletplugin.yaml

@@ -66,6 +66,8 @@ spec:
           mountPath: /var/lib/kubelet/plugins
         - name: cdi
           mountPath: /var/run/cdi
+        - name: host-sys
+          mountPath: /host-sys
       volumes:
       - name: plugins-registry
         hostPath:
@@ -75,6 +77,10 @@ spec:
         hostPath:
           path: /var/lib/kubelet/plugins
           type: Directory
+      - name: host-sys
+        hostPath:
+          path: /sys
+          type: Directory
       - name: cdi
         hostPath:
           path: /var/run/cdi