diff --git a/discovery/pkg/util/util.go b/discovery/pkg/util/util.go
index 360a636e..705b7d48 100644
--- a/discovery/pkg/util/util.go
+++ b/discovery/pkg/util/util.go
@@ -29,7 +29,7 @@ func GetFormatter() *logrus.TextFormatter {
 
 // IsInvalidClusterName returns true if valid cluster name
 func IsInvalidClusterName(clustername string) bool {
-	matched, err := regexp.MatchString("^[a-zA-Z0-9]+[a-zA-Z0-9-]*[a-zA-Z0-9]+$", clustername)
+	matched, err := regexp.MatchString("^[a-z]([-a-z0-9]*[a-z0-9])?$", clustername)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/docs/kubernetes-discoverer.md b/docs/kubernetes-discoverer.md
index 906455c4..c75c3b57 100644
--- a/docs/kubernetes-discoverer.md
+++ b/docs/kubernetes-discoverer.md
@@ -22,7 +22,7 @@ Arguments are available to customize the discoverer, most have defaults but othe
 | num-threads  | 2  |  Specify number of threads to use when processing queue items
 | gimbal-kubecfg-file  | ""  | Location of kubecfg file for access to Kubernetes cluster hosting Gimbal
 | discover-kubecfg-file | ""  | Location of kubecfg file for access to remote Kubernetes cluster to watch for services / endpoints 
-| cluster-name  | ""  |   Name of cluster scraping for services & endpoints (Cannot start or end with a hyphen and must be alpha-numeric)
+| cluster-name  | ""  |   Name of cluster scraping for services & endpoints (Cannot start or end with a hyphen and must be lowercase alpha-numeric)
 | debug | false | Enable debug logging 
 
 ### Credentials
diff --git a/docs/openstack-discoverer.md b/docs/openstack-discoverer.md
index f7812d2c..1083a04c 100644
--- a/docs/openstack-discoverer.md
+++ b/docs/openstack-discoverer.md
@@ -21,7 +21,7 @@ Arguments are available to customize the discoverer, most have defaults but othe
 | version  |  false | Show version, build information and quit  
 | num-threads  | 2  |  Specify number of threads to use when processing queue items
 | gimbal-kubecfg-file  | ""  | Location of kubecfg file for access to Kubernetes cluster hosting Gimbal
-| cluster-name  | ""  |   Name of cluster scraping for services & endpoints (Cannot start or end with a hyphen and must be alpha-numeric)
+| cluster-name  | ""  |   Name of cluster scraping for services & endpoints (Cannot start or end with a hyphen and must be lowercase alpha-numeric)
 | debug | false | Enable debug logging 
 | reconciliation-period | 30s | The interval of time between reconciliation loop runs 
 | http-client-timeout | 5s | The HTTP client request timeout