diff --git a/modules/jenkins/manifests/slave.pp b/modules/jenkins/manifests/slave.pp
index e19742798e..f55625d602 100644
--- a/modules/jenkins/manifests/slave.pp
+++ b/modules/jenkins/manifests/slave.pp
@@ -39,7 +39,7 @@ class jenkins::slave(
     'RedHat': {
 
       exec { 'yum Group Install':
-        unless  => '/usr/bin/yum grouplist "Development tools" | /bin/grep "^Installed Groups"',
+        unless  => '/usr/bin/yum grouplist "Development tools" | /bin/grep "^Installed [Gg]roups"',
         command => '/usr/bin/yum -y groupinstall "Development tools"',
       }