diff --git a/app/kubernetes/views/resource-pools/create/createResourcePool.html b/app/kubernetes/views/resource-pools/create/createResourcePool.html
index 8529a0395..611c2bc45 100644
--- a/app/kubernetes/views/resource-pools/create/createResourcePool.html
+++ b/app/kubernetes/views/resource-pools/create/createResourcePool.html
@@ -269,6 +269,7 @@
                             ng-model="item.Host"
                             ng-change="$ctrl.onChangeIngressHostname()"
                             placeholder="foo"
+                            pattern="[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*"
                             required
                           />
                         </div>
@@ -288,6 +289,10 @@
                       >
                         <ng-messages for="resourcePoolCreationForm['hostname_' + ic.IngressClass.Name + '_' + $index].$error">
                           <p ng-message="required"><i class="fa fa-exclamation-triangle" aria-hidden="true"></i> Hostname is required.</p>
+                          <p ng-message="pattern">
+                            <i class="fa fa-exclamation-triangle" aria-hidden="true"></i>
+                            This field must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com').
+                          </p>
                         </ng-messages>
                         <p ng-if="$ctrl.state.duplicates.ingressHosts.refs[ic.IngressClass.Name][$index] !== undefined">
                           <i class="fa fa-exclamation-triangle" aria-hidden="true"></i> This hostname is already used.
diff --git a/app/kubernetes/views/resource-pools/create/createResourcePoolController.js b/app/kubernetes/views/resource-pools/create/createResourcePoolController.js
index 5cdc8accc..92149f4f9 100644
--- a/app/kubernetes/views/resource-pools/create/createResourcePoolController.js
+++ b/app/kubernetes/views/resource-pools/create/createResourcePoolController.js
@@ -34,7 +34,7 @@ class KubernetesCreateResourcePoolController {
   onChangeIngressHostname() {
     const state = this.state.duplicates.ingressHosts;
     const hosts = _.flatMap(this.formValues.IngressClasses, 'Hosts');
-    const hostnames = _.map(hosts, 'Host');
+    const hostnames = _.compact(hosts.map((h) => h.Host));
     const hostnamesWithoutRemoved = _.filter(hostnames, (h) => !h.NeedsDeletion);
     const allHosts = _.flatMap(this.allIngresses, 'Hosts');
     const formDuplicates = KubernetesFormValidationHelper.getDuplicates(hostnamesWithoutRemoved);
diff --git a/app/kubernetes/views/resource-pools/edit/resourcePool.html b/app/kubernetes/views/resource-pools/edit/resourcePool.html
index 29d39b3a4..d847527e0 100644
--- a/app/kubernetes/views/resource-pools/edit/resourcePool.html
+++ b/app/kubernetes/views/resource-pools/edit/resourcePool.html
@@ -221,6 +221,7 @@
                                 ng-model="item.Host"
                                 ng-change="ctrl.onChangeIngressHostname()"
                                 placeholder="foo"
+                                pattern="[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*"
                                 required
                               />
                             </div>
@@ -240,6 +241,11 @@
                           >
                             <ng-messages for="resourcePoolEditForm['hostname_' + ic.IngressClass.Name + '_' + $index].$error">
                               <p ng-message="required"><i class="fa fa-exclamation-triangle" aria-hidden="true"></i> Hostname is required.</p>
+                              <p ng-message="pattern">
+                                <i class="fa fa-exclamation-triangle" aria-hidden="true"></i>
+                                This field must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g.
+                                'example.com').
+                              </p>
                             </ng-messages>
                             <p ng-if="item.Duplicate">
                               <i class="fa fa-exclamation-triangle" aria-hidden="true"></i>