Add experimental option to NVIDIA Container Runtime config

This change adds an experimental option to the NVIDIA Container Runtime config. To
simplify the extension of this experimental mode in future an error is raised if
this is enabled.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

cmd/nvidia-container-runtime/main.go

@@ -47,16 +47,17 @@ func run(argv []string) (rerr error) {
 		logger.CloseFile()
 	}()
 
-	r, err := newNVIDIAContainerRuntime(logger.Logger, cfg, argv)
+	runtime, err := newNVIDIAContainerRuntime(logger.Logger, cfg, argv)
 	if err != nil {
 		return fmt.Errorf("error creating runtime: %v", err)
 	}
 
-	return r.Exec(argv)
+	return runtime.Exec(argv)
 }
 
 type config struct {
 	debugFilePath string
+	Experimental  bool
 }
 
 // getConfig sets up the config struct. Values are read from a toml file
@@ -81,6 +82,7 @@ func getConfig() (*config, error) {
 	}
 
 	cfg.debugFilePath = toml.GetDefault("nvidia-container-runtime.debug", "/dev/null").(string)
+	cfg.Experimental = toml.GetDefault("nvidia-container-runtime.experimental", false).(bool)
 
 	return cfg, nil
 }

cmd/nvidia-container-runtime/runtime_factory.go

@@ -43,7 +43,11 @@ func newNVIDIAContainerRuntime(logger *logrus.Logger, cfg *config, argv []string
 		return nil, fmt.Errorf("error constructing low-level runtime: %v", err)
 	}
 
-	specModifier := modifier.NewStableRuntimeModifier(logger)
+	var specModifier oci.SpecModifier
+	if cfg.Experimental {
+		return nil, fmt.Errorf("experimental mode is not supported")
+	}
+	specModifier = modifier.NewStableRuntimeModifier(logger)
 
 	// Create the wrapping runtime with the specified modifier
 	r := runtime.NewModifyingRuntimeWrapper(