Allow container runtime executable path to be specified

This change adds support for specifying the container runtime
executable path. This can be used if, for example, there are
two containerd executables and a specific one must be used.

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

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

@@ -38,6 +38,11 @@ const (
 type Options struct {
 	Config string
 	Socket string
+	// ExecutablePath specifies the path to the container runtime executable.
+	// This is used to extract the current config, for example.
+	// If a HostRootMount is specified, this path is relative to the host root
+	// mount.
+	ExecutablePath string
 	// EnabledCDI indicates whether CDI should be enabled.
 	EnableCDI     bool
 	RuntimeName   string

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

@@ -173,7 +173,7 @@ func getRuntimeConfig(o *container.Options, co *Options) (engine.Interface, erro
 		containerd.WithPath(o.Config),
 		containerd.WithConfigSource(
 			toml.LoadFirst(
-				containerd.CommandLineSource(o.HostRootMount),
+				containerd.CommandLineSource(o.HostRootMount, o.ExecutablePath),
 				toml.FromFile(o.Config),
 			),
 		),

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

@@ -26,6 +26,7 @@ import (
 	"github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-ctk-installer/container/runtime/crio"
 	"github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-ctk-installer/container/runtime/docker"
 	"github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-ctk-installer/container/toolkit"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/logger"
 )
 
 const (
@@ -53,6 +54,12 @@ func Flags(opts *Options) []cli.Flag {
 			Destination: &opts.Config,
 			EnvVars:     []string{"RUNTIME_CONFIG", "CONTAINERD_CONFIG", "DOCKER_CONFIG"},
 		},
+		&cli.StringFlag{
+			Name:        "executable-path",
+			Usage:       "The path to the runtime executable. This is used to extract the current config",
+			Destination: &opts.ExecutablePath,
+			EnvVars:     []string{"RUNTIME_EXECUTABLE_PATH"},
+		},
 		&cli.StringFlag{
 			Name:        "socket",
 			Usage:       "Path to the runtime socket file",
@@ -104,8 +111,8 @@ func Flags(opts *Options) []cli.Flag {
 	return flags
 }
 
-// ValidateOptions checks whether the specified options are valid
+// Validate checks whether the specified options are valid
-func ValidateOptions(c *cli.Context, opts *Options, runtime string, toolkitRoot string, to *toolkit.Options) error {
+func (opts *Options) Validate(logger logger.Interface, c *cli.Context, runtime string, toolkitRoot string, to *toolkit.Options) error {
 	// We set this option here to ensure that it is available in future calls.
 	opts.RuntimeDir = toolkitRoot
 
@@ -113,6 +120,11 @@ func ValidateOptions(c *cli.Context, opts *Options, runtime string, toolkitRoot
 		opts.EnableCDI = to.CDI.Enabled
 	}
 
+	if opts.ExecutablePath != "" && opts.RuntimeName != containerd.Name {
+		logger.Warningf("Ignoring executable-path=%q flag for %v", opts.ExecutablePath, opts.RuntimeName)
+		opts.ExecutablePath = ""
+	}
+
 	// Apply the runtime-specific config changes.
 	switch runtime {
 	case containerd.Name:

cmd/nvidia-ctk-installer/main.go

@@ -167,7 +167,7 @@ func (a *app) validateFlags(c *cli.Context, o *options) error {
 	if err := a.toolkit.ValidateOptions(&o.toolkitOptions); err != nil {
 		return err
 	}
-	if err := runtime.ValidateOptions(c, &o.runtimeOptions, o.runtime, o.toolkitRoot(), &o.toolkitOptions); err != nil {
+	if err := o.runtimeOptions.Validate(a.logger, c, o.runtime, o.toolkitRoot(), &o.toolkitOptions); err != nil {
 		return err
 	}
 	return nil

cmd/nvidia-ctk/runtime/configure/configure.go

@@ -68,6 +68,7 @@ type config struct {
 	dryRun         bool
 	runtime        string
 	configFilePath string
+	executablePath string
 	configSource   string
 	mode           string
 	hookFilePath   string
@@ -120,6 +121,11 @@ func (m command) build() *cli.Command {
 			Usage:       "path to the config file for the target runtime",
 			Destination: &config.configFilePath,
 		},
+		&cli.StringFlag{
+			Name:        "executable-path",
+			Usage:       "The path to the runtime executable. This is used to extract the current config",
+			Destination: &config.executablePath,
+		},
 		&cli.StringFlag{
 			Name:        "config-mode",
 			Usage:       "the config mode for runtimes that support multiple configuration mechanisms",
@@ -208,6 +214,11 @@ func (m command) validateFlags(c *cli.Context, config *config) error {
 		config.cdi.enabled = false
 	}
 
+	if config.executablePath != "" && config.runtime != "containerd" {
+		m.logger.Warningf("Ignoring executable-path=%q flag for %v", config.executablePath, config.runtime)
+		config.executablePath = ""
+	}
+
 	if config.runtimeConfigOverrideJSON != "" && config.runtime != "containerd" {
 		m.logger.Warningf("Ignoring runtime-config-override flag for %v", config.runtime)
 		config.runtimeConfigOverrideJSON = ""
@@ -330,7 +341,7 @@ func (c *config) resolveConfigSource() (toml.Loader, error) {
 func (c *config) getCommandConfigSource() toml.Loader {
 	switch c.runtime {
 	case "containerd":
-		return containerd.CommandLineSource("")
+		return containerd.CommandLineSource("", c.executablePath)
 	case "crio":
 		return crio.CommandLineSource("")
 	}

pkg/config/engine/containerd/containerd.go

@@ -162,8 +162,11 @@ func (c *Config) GetRuntimeConfig(name string) (engine.RuntimeConfig, error) {
 }
 
 // CommandLineSource returns the CLI-based containerd config loader
-func CommandLineSource(hostRoot string) toml.Loader {
+func CommandLineSource(hostRoot string, executablePath string) toml.Loader {
-	return toml.FromCommandLine(chrootIfRequired(hostRoot, "containerd", "config", "dump")...)
+	if executablePath == "" {
+		executablePath = "containerd"
+	}
+	return toml.FromCommandLine(chrootIfRequired(hostRoot, executablePath, "config", "dump")...)
 }
 
 func chrootIfRequired(hostRoot string, commandLine ...string) []string {