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 or crio executables and a specific one must be used.

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

tools/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),
 			),
 		),

tools/container/runtime/crio/crio.go

@@ -202,7 +202,7 @@ func getRuntimeConfig(o *container.Options) (engine.Interface, error) {
 		crio.WithPath(o.Config),
 		crio.WithConfigSource(
 			toml.LoadFirst(
-				crio.CommandLineSource(o.HostRootMount),
+				crio.CommandLineSource(o.HostRootMount, o.ExecutablePath),
 				toml.FromFile(o.Config),
 			),
 		),

tools/container/runtime/runtime.go

@@ -19,6 +19,7 @@ package runtime
 import (
 	"fmt"
 
+	log "github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 
 	"github.com/NVIDIA/nvidia-container-toolkit/tools/container"
@@ -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
-func ValidateOptions(c *cli.Context, opts *Options, runtime string, toolkitRoot string, to *toolkit.Options) error {
+// Validate checks whether the specified options are valid
+func (opts *Options) Validate(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 == docker.Name {
+		log.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: