diff --git a/clab/clab.go b/clab/clab.go
index 1be470992..e158648b8 100644
--- a/clab/clab.go
+++ b/clab/clab.go
@@ -23,6 +23,8 @@ import (
 	"github.com/srl-labs/containerlab/types"
 )
 
+var once sync.Once // nolint:gochecknoglobals
+
 type CLab struct {
 	Config        *Config   `json:"config,omitempty"`
 	TopoFile      *TopoFile `json:"topofile,omitempty"`
@@ -111,7 +113,8 @@ func WithTopoFile(file, varsFile string) ClabOption {
 
 // NewContainerLab function defines a new container lab.
 func NewContainerLab(opts ...ClabOption) (*CLab, error) {
-	allNodes.RegisterAll()
+	// register all nodes just once
+	once.Do(allNodes.RegisterAll)
 
 	c := &CLab{
 		Config: &Config{