Avoid resetting the VF if the netns does not exist

The VF might have been assigned to another running
Pod if the network namespace is not present. In cases
like this, resetting the VF might break the configuration
of the running Pod.
The above scenario might occur when the IPAM plugin takes a lot of time to complete, and the CmdDel gets called
multiple times.

Check if the namespace is still present before resetting the VF

Signed-off-by: Andrea Panattoni <[email protected]>

cmd/sriov/main.go

@@ -270,6 +270,26 @@ func cmdDel(args *skel.CmdArgs) error {
 
 	sm := sriov.NewSriovManager()
 
+	netns, err := ns.GetNS(args.Netns)
+	if err != nil {
+		// according to:
+		// https://github.com/kubernetes/kubernetes/issues/43014#issuecomment-287164444
+		// if provided path does not exist (e.x. when node was restarted)
+		// plugin should silently return with success after releasing
+		// IPAM resources
+		_, ok := err.(ns.NSPathNotExistErr)
+		if ok {
+			logging.Debug("Exiting as the network namespace does not exists anymore",
+				"func", "cmdDel",
+				"netConf.DeviceID", netConf.DeviceID,
+				"args.Netns", args.Netns)
+			return nil
+		}
+
+		return fmt.Errorf("failed to open netns %s: %q", netns, err)
+	}
+	defer netns.Close()
+
 	logging.Debug("Reset VF configuration",
 		"func", "cmdDel",
 		"netConf.DeviceID", netConf.DeviceID)
@@ -282,26 +302,6 @@ func cmdDel(args *skel.CmdArgs) error {
 	}
 
 	if !netConf.DPDKMode {
-		netns, err := ns.GetNS(args.Netns)
-		if err != nil {
-			// according to:
-			// https://github.com/kubernetes/kubernetes/issues/43014#issuecomment-287164444
-			// if provided path does not exist (e.x. when node was restarted)
-			// plugin should silently return with success after releasing
-			// IPAM resources
-			_, ok := err.(ns.NSPathNotExistErr)
-			if ok {
-				logging.Debug("Exiting as the network namespace does not exists anymore",
-					"func", "cmdDel",
-					"netConf.DeviceID", netConf.DeviceID,
-					"args.Netns", args.Netns)
-				return nil
-			}
-
-			return fmt.Errorf("failed to open netns %s: %q", netns, err)
-		}
-		defer netns.Close()
-
 		logging.Debug("Release the VF",
 			"func", "cmdDel",
 			"netConf.DeviceID", netConf.DeviceID,