diff --git a/modules/jenkins/manifests/master.pp b/modules/jenkins/manifests/master.pp
index 9601ff5f04..a54108647b 100644
--- a/modules/jenkins/manifests/master.pp
+++ b/modules/jenkins/manifests/master.pp
@@ -51,14 +51,20 @@ class jenkins::master(
     template => 'jenkins/jenkins.vhost.erb',
     ssl      => true,
   }
-  a2mod { 'rewrite':
-    ensure => present,
+  if ! defined(A2mod['rewrite']) {
+    a2mod { 'rewrite':
+      ensure => present,
+    }
   }
-  a2mod { 'proxy':
-    ensure => present,
+  if ! defined(A2mod['proxy']) {
+    a2mod { 'proxy':
+      ensure => present,
+    }
   }
-  a2mod { 'proxy_http':
-    ensure => present,
+  if ! defined(A2mod['proxy_http']) {
+    a2mod { 'proxy_http':
+      ensure => present,
+    }
   }
 
   if $ssl_cert_file_contents != '' {
diff --git a/modules/zuul/manifests/init.pp b/modules/zuul/manifests/init.pp
index b7786512f3..3bb13d9296 100644
--- a/modules/zuul/manifests/init.pp
+++ b/modules/zuul/manifests/init.pp
@@ -231,13 +231,19 @@ class zuul (
     priority => '50',
     template => 'zuul/zuul.vhost.erb',
   }
-  a2mod { 'rewrite':
-    ensure => present,
+  if ! defined(A2mod['rewrite']) {
+    a2mod { 'rewrite':
+      ensure => present,
+    }
   }
-  a2mod { 'proxy':
-    ensure => present,
+  if ! defined(A2mod['proxy']) {
+    a2mod { 'proxy':
+      ensure => present,
+    }
   }
-  a2mod { 'proxy_http':
-    ensure => present,
+  if ! defined(A2mod['proxy_http']) {
+    a2mod { 'proxy_http':
+      ensure => present,
+    }
   }
 }