*: implement additional pull registries

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

cmd/crio/config.go

@@ -135,6 +135,11 @@ image_volumes = "{{ .ImageVolumes }}"
 insecure_registries = [
 {{ range $opt := .InsecureRegistries }}{{ printf "\t%q,\n" $opt }}{{ end }}]
 
+# registries is used to specify a comma separated list of registries to be used
+# when pulling an unqualified image (e.g. fedora:rawhide).
+registries = [
+{{ range $opt := .Registries }}{{ printf "\t%q,\n" $opt }}{{ end }}]
+
 # The "crio.network" table contains settings pertaining to the
 # management of CNI plugins.
 [crio.network]

cmd/crio/main.go

@@ -81,6 +81,9 @@ func mergeConfig(config *server.Config, ctx *cli.Context) error {
 	if ctx.GlobalIsSet("insecure-registry") {
 		config.InsecureRegistries = ctx.GlobalStringSlice("insecure-registry")
 	}
+	if ctx.GlobalIsSet("registry") {
+		config.Registries = ctx.GlobalStringSlice("registry")
+	}
 	if ctx.GlobalIsSet("default-transport") {
 		config.DefaultTransport = ctx.GlobalString("default-transport")
 	}
@@ -227,6 +230,10 @@ func main() {
 			Name:  "insecure-registry",
 			Usage: "whether to disable TLS verification for the given registry",
 		},
+		cli.StringSliceFlag{
+			Name:  "registry",
+			Usage: "registry to be prepended when pulling unqualified images, can be specified multiple times",
+		},
 		cli.StringFlag{
 			Name:  "default-transport",
 			Usage: "default transport",