config: Add ImageVolumes configuration setting

Signed-off-by: Mrunal Patel <mpatel@redhat.com>

cmd/crio/config.go

@@ -120,6 +120,10 @@ pause_command = "{{ .PauseCommand }}"
 # unspecified so that the default system-wide policy will be used.
 signature_policy = "{{ .SignaturePolicyPath }}"
 
+# image_volumes controls how image volumes are handled.
+# The valid values are mkdir and ignore.
+image_volumes = "{{ .ImageVolumes }}"
+
 # insecure_registries is used to skip TLS verification when pulling images.
 insecure_registries = [
 {{ range $opt := .InsecureRegistries }}{{ printf "\t%q,\n" $opt }}{{ end }}]

cmd/crio/main.go

@@ -22,6 +22,17 @@ import (
 
 const crioConfigPath = "/etc/crio/crio.conf"
 
+func validateConfig(config *server.Config) error {
+	switch config.ImageVolumes {
+	case server.ImageVolumesMkdir:
+	case server.ImageVolumesIgnore:
+	default:
+		return fmt.Errorf("Unrecognized image volume type specified")
+
+	}
+	return nil
+}
+
 func mergeConfig(config *server.Config, ctx *cli.Context) error {
 	// Don't parse the config if the user explicitly set it to "".
 	if path := ctx.GlobalString("config"); path != "" {
@@ -98,6 +109,9 @@ func mergeConfig(config *server.Config, ctx *cli.Context) error {
 	if ctx.GlobalIsSet("cni-plugin-dir") {
 		config.PluginDir = ctx.GlobalString("cni-plugin-dir")
 	}
+	if ctx.GlobalIsSet("image-volumes") {
+		config.ImageVolumes = server.ImageVolumesType(ctx.GlobalString("image-volumes"))
+	}
 	return nil
 }
 
@@ -233,6 +247,11 @@ func main() {
 			Name:  "cni-plugin-dir",
 			Usage: "CNI plugin binaries directory",
 		},
+		cli.StringFlag{
+			Name:  "image-volumes",
+			Value: string(server.ImageVolumesMkdir),
+			Usage: "image volume handling ('mkdir' or 'ignore')",
+		},
 		cli.BoolFlag{
 			Name:  "profile",
 			Usage: "enable pprof remote profiler on localhost:6060",
@@ -253,6 +272,10 @@ func main() {
 			return err
 		}
 
+		if err := validateConfig(config); err != nil {
+			return err
+		}
+
 		cf := &logrus.TextFormatter{
 			TimestampFormat: "2006-01-02 15:04:05.000000000Z07:00",
 			FullTimestamp:   true,

server/config.go

@@ -33,6 +33,16 @@ type Config struct {
 	NetworkConfig
 }
 
+// ImageVolumesType describes image volume handling strategies
+type ImageVolumesType string
+
+const (
+	// ImageVolumesMkdir option is for using mkdir to handle image volumes
+	ImageVolumesMkdir ImageVolumesType = "mkdir"
+	// ImageVolumesIgnore option is for ignoring image volumes altogether
+	ImageVolumesIgnore ImageVolumesType = "ignore"
+)
+
 // This structure is necessary to fake the TOML tables when parsing,
 // while also not requiring a bunch of layered structs for no good
 // reason.
@@ -145,6 +155,8 @@ type ImageConfig struct {
 	// InsecureRegistries is a list of registries that must be contacted w/o
 	// TLS verification.
 	InsecureRegistries []string `toml:"insecure_registries"`
+	// ImageVolumes controls how volumes specified in image config are handled
+	ImageVolumes ImageVolumesType `toml:"image_volumes"`
 }
 
 // NetworkConfig represents the "crio.network" TOML config table
@@ -255,6 +267,7 @@ func DefaultConfig() *Config {
 			PauseImage:          pauseImage,
 			PauseCommand:        pauseCommand,
 			SignaturePolicyPath: "",
+			ImageVolumes:        ImageVolumesMkdir,
 		},
 		NetworkConfig: NetworkConfig{
 			NetworkDir: cniConfigDir,