diff --git a/modules/installation-configuration-parameters.adoc b/modules/installation-configuration-parameters.adoc
index 2b0023ab1e5a..04fe9ae7624f 100644
--- a/modules/installation-configuration-parameters.adoc
+++ b/modules/installation-configuration-parameters.adoc
@@ -283,6 +283,10 @@ ifdef::osp[]
 `clouds.yaml` file.
 |String, for example `MyCloud`.
 
+|`machines.platform.openstack.externalDNS`
+|_Optional_. IP addresses for external DNS servers that cluster instances use for DNS resolution.
+|A list of IP addresses as strings, for example `["8.8.8.8", "192.168.1.12"]`.
+
 |`machines.platform.openstack.externalNetwork`
 |The {rh-openstack} external network name to be used for installation.
 |String, for example `external`.