K8s: Dashboards: Add useful error message for too large (#101590)

pkg/services/apiserver/service.go

@@ -80,6 +80,8 @@ var (
 	ready      = make(chan struct{})
 )
 
+const MaxRequestBodyBytes = 16 * 1024 * 1024 // 16MB - determined by the size of `mediumtext` on mysql, which is used to save dashboard data
+
 func init() {
 	// we need to add the options to empty v1
 	metav1.AddToGroupVersion(Scheme, schema.GroupVersion{Group: "", Version: "v1"})
@@ -335,7 +337,7 @@ func (s *service) start(ctx context.Context) error {
 	transport := &roundTripperFunc{ready: make(chan struct{})}
 	serverConfig.LoopbackClientConfig.Transport = transport
 	serverConfig.LoopbackClientConfig.TLSClientConfig = clientrest.TLSClientConfig{}
-	serverConfig.MaxRequestBodyBytes = 16 * 1024 * 1024 // 16MB - determined by the size of `mediumtext` on mysql, which is used to save dashboard data
+	serverConfig.MaxRequestBodyBytes = MaxRequestBodyBytes
 
 	var optsregister apistore.StorageOptionsRegister