diff --git a/contrib/terraform/openstack/README.md b/contrib/terraform/openstack/README.md
index 0e144c2be..5566b1c65 100644
--- a/contrib/terraform/openstack/README.md
+++ b/contrib/terraform/openstack/README.md
@@ -294,7 +294,8 @@ For your cluster, edit `inventory/$CLUSTER/cluster.tfvars`.
 Allows a custom definition of worker nodes giving the operator full control over individual node flavor and
 availability zone placement. To enable the use of this mode set the `number_of_k8s_nodes` and
 `number_of_k8s_nodes_no_floating_ip` variables to 0. Then define your desired worker node configuration
-using the `k8s_nodes` variable.
+using the `k8s_nodes` variable. The `az`, `flavor` and `floating_ip` parameters are mandatory.
+The optional parameter `extra_groups` (a comma-delimited string) can be used to define extra inventory group memberships for specific nodes.
 
 For example:
 
@@ -314,6 +315,7 @@ k8s_nodes = {
     "az" = "sto3"
     "flavor" = "83d8b44a-26a0-4f02-a981-079446926445"
     "floating_ip" = true
+    "extra_groups" = "calico_rr"
   }
 }
 ```
diff --git a/contrib/terraform/openstack/modules/compute/main.tf b/contrib/terraform/openstack/modules/compute/main.tf
index 15470dc2e..82cbbb4dd 100644
--- a/contrib/terraform/openstack/modules/compute/main.tf
+++ b/contrib/terraform/openstack/modules/compute/main.tf
@@ -742,7 +742,7 @@ resource "openstack_compute_instance_v2" "k8s_nodes" {
 
   metadata = {
     ssh_user         = var.ssh_user
-    kubespray_groups = "kube_node,k8s_cluster,%{if each.value.floating_ip == false}no_floating,%{endif}${var.supplementary_node_groups}"
+    kubespray_groups = "kube_node,k8s_cluster,%{if each.value.floating_ip == false}no_floating,%{endif}${var.supplementary_node_groups},${try(each.value.extra_groups, "")}"
     depends_on       = var.network_router_id
     use_access_ip    = var.use_access_ip
   }