Add none runtime to toolkit installer

This change adds a "none" runtime to the toolkit installer to enable
use cases where the NVIDIA Container Toolkit is required without
configuring the underlying runtime.

Signed-off-by: Evan Lezar <[email protected]>

Author: elezar

cmd/nvidia-ctk-installer/container/runtime/runtime.go

@@ -138,6 +138,18 @@ func Flags(opts *Options) []cli.Flag {
 
 // Validate checks whether the specified options are valid
 func (opts *Options) Validate(logger logger.Interface, c *cli.Command, runtime string, toolkitRoot string, to *toolkit.Options) error {
+	// Check that the specified runtime is supported.
+	switch runtime {
+	case containerd.Name:
+	case crio.Name:
+	case docker.Name:
+	case string(None):
+		// If the none runtime is selected, we bypass any additional validations.
+		return nil
+	default:
+		return fmt.Errorf("invalid runtime %q; expected one of [containerd | crio | docker | none]", runtime)
+	}
+
 	// We set this option here to ensure that it is available in future calls.
 	opts.RuntimeDir = toolkitRoot
 
@@ -212,40 +224,51 @@ func (opts *Options) Validate(logger logger.Interface, c *cli.Command, runtime s
 	return nil
 }
 
-func Setup(c *cli.Command, opts *Options, runtime string) error {
-	switch runtime {
+type Runtime string
+
+// A None runtime is used to disable runtime configuration.
+const None Runtime = "none"
+
+func (r Runtime) Setup(c *cli.Command, opts *Options) error {
+	switch string(r) {
 	case containerd.Name:
 		return containerd.Setup(c, &opts.Options, &opts.containerdOptions)
 	case crio.Name:
 		return crio.Setup(c, &opts.Options, &opts.crioOptions)
 	case docker.Name:
 		return docker.Setup(c, &opts.Options)
+	case string(None):
+		return nil
 	default:
-		return fmt.Errorf("undefined runtime %v", runtime)
+		return fmt.Errorf("undefined runtime %v", r)
 	}
 }
 
-func Cleanup(c *cli.Command, opts *Options, runtime string) error {
-	switch runtime {
+func (r Runtime) Cleanup(c *cli.Command, opts *Options, runtime string) error {
+	switch string(r) {
 	case containerd.Name:
 		return containerd.Cleanup(c, &opts.Options, &opts.containerdOptions)
 	case crio.Name:
 		return crio.Cleanup(c, &opts.Options, &opts.crioOptions)
 	case docker.Name:
 		return docker.Cleanup(c, &opts.Options)
+	case string(None):
+		return nil
 	default:
 		return fmt.Errorf("undefined runtime %v", runtime)
 	}
 }
 
-func GetLowlevelRuntimePaths(opts *Options, runtime string) ([]string, error) {
+func (r Runtime) GetLowlevelRuntimePaths(opts *Options, runtime string) ([]string, error) {
 	switch runtime {
 	case containerd.Name:
 		return containerd.GetLowlevelRuntimePaths(&opts.Options, &opts.containerdOptions)
 	case crio.Name:
 		return crio.GetLowlevelRuntimePaths(&opts.Options)
 	case docker.Name:
 		return docker.GetLowlevelRuntimePaths(&opts.Options)
+	case string(None):
+		return nil, nil
 	default:
 		return nil, fmt.Errorf("undefined runtime %v", runtime)
 	}

cmd/nvidia-ctk-installer/main.go

@@ -175,19 +175,18 @@ func (a *app) validateFlags(c *cli.Command, o *options) error {
 	if o.toolkitInstallDir == "" {
 		return fmt.Errorf("the install root must be specified")
 	}
-	if _, exists := availableRuntimes[o.runtime]; !exists {
-		return fmt.Errorf("unknown runtime: %v", o.runtime)
-	}
 	if filepath.Base(o.pidFile) != toolkitPidFilename {
 		return fmt.Errorf("invalid toolkit.pid path %v", o.pidFile)
 	}
 
 	if err := a.toolkit.ValidateOptions(&o.toolkitOptions); err != nil {
 		return err
 	}
+
 	if err := o.runtimeOptions.Validate(a.logger, c, o.runtime, o.toolkitRoot(), &o.toolkitOptions); err != nil {
 		return err
 	}
+
 	return nil
 }
 
@@ -201,6 +200,8 @@ func (a *app) Run(c *cli.Command, o *options) error {
 	}
 	defer a.shutdown(o.pidFile)
 
+	runtime := runtime.Runtime(o.runtime)
+
 	if len(o.toolkitOptions.ContainerRuntimeRuntimes) == 0 {
 		lowlevelRuntimePaths, err := runtime.GetLowlevelRuntimePaths(&o.runtimeOptions, o.runtime)
 		if err != nil {
@@ -216,21 +217,22 @@ func (a *app) Run(c *cli.Command, o *options) error {
 		return fmt.Errorf("unable to install toolkit: %v", err)
 	}
 
-	err = runtime.Setup(c, &o.runtimeOptions, o.runtime)
+	err = runtime.Setup(c, &o.runtimeOptions)
 	if err != nil {
 		return fmt.Errorf("unable to setup runtime: %v", err)
 	}
+	if o.noDaemon {
+		return nil
+	}
 
-	if !o.noDaemon {
-		err = a.waitForSignal()
-		if err != nil {
-			return fmt.Errorf("unable to wait for signal: %v", err)
-		}
+	err = a.waitForSignal()
+	if err != nil {
+		return fmt.Errorf("unable to wait for signal: %v", err)
+	}
 
-		err = runtime.Cleanup(c, &o.runtimeOptions, o.runtime)
-		if err != nil {
-			return fmt.Errorf("unable to cleanup runtime: %v", err)
-		}
+	err = runtime.Cleanup(c, &o.runtimeOptions, o.runtime)
+	if err != nil {
+		return fmt.Errorf("unable to cleanup runtime: %v", err)
 	}
 
 	return nil