diff --git a/clab/clab.go b/clab/clab.go
index 764648e26..8112dfaac 100644
--- a/clab/clab.go
+++ b/clab/clab.go
@@ -7,6 +7,7 @@ package clab
 import (
 	"context"
 	"fmt"
+	"os"
 	"path"
 	"strings"
 	"sync"
@@ -58,6 +59,12 @@ func WithTimeout(dur time.Duration) ClabOption {
 
 func WithRuntime(name string, d bool, dur time.Duration, gracefulShutdown bool) ClabOption {
 	return func(c *CLab) {
+		if name == "" {
+			name = os.Getenv("CLAB_RUNTIME")
+			if name == "" {
+				name = runtime.DockerRuntime
+			}
+		}
 		if rInit, ok := runtime.ContainerRuntimes[name]; ok {
 			c.Runtime = rInit()
 			err := c.Runtime.Init(
diff --git a/cmd/root.go b/cmd/root.go
index f5ade243e..6772500b4 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -11,7 +11,6 @@ import (
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
-	"github.com/srl-labs/containerlab/runtime"
 )
 
 var debug bool
@@ -52,8 +51,7 @@ func init() {
 	_ = rootCmd.MarkPersistentFlagFilename("topo", "*.yaml", "*.yml")
 	rootCmd.PersistentFlags().StringVarP(&name, "name", "n", "", "lab name")
 	rootCmd.PersistentFlags().DurationVarP(&timeout, "timeout", "", 30*time.Second, "timeout for docker requests, e.g: 30s, 1m, 2m30s")
-	rootCmd.PersistentFlags().StringVarP(&rt, "runtime", "r", runtime.DockerRuntime, "container runtime")
-
+	rootCmd.PersistentFlags().StringVarP(&rt, "runtime", "r", "", "container runtime")
 }
 
 // returns an error if topo path is not provided